| Message ID | 20220124131118.17887-7-yangyicong@hisilicon.com (mailing list archive) |
|---|---|
| State | Superseded |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
| Series | Add support for HiSilicon PCIe Tune and Trace device | expand |
On Mon, 24 Jan 2022 21:11:16 +0800 Yicong Yang <yangyicong@hisilicon.com> wrote: > Document the introduction and usage of HiSilicon PTT device driver. > > Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> Nice document. A few trivial typos inline. I would give a RB except I've suggested you change a part of the sysfs interface which will affect the relevant documentation. Thanks, Jonathan > --- > Documentation/trace/hisi-ptt.rst | 304 +++++++++++++++++++++++++++++++ > 1 file changed, 304 insertions(+) > create mode 100644 Documentation/trace/hisi-ptt.rst > > diff --git a/Documentation/trace/hisi-ptt.rst b/Documentation/trace/hisi-ptt.rst > new file mode 100644 > index 000000000000..f3269b11a2f6 > --- /dev/null > +++ b/Documentation/trace/hisi-ptt.rst > @@ -0,0 +1,304 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +====================================== > +HiSilicon PCIe Tune and Trace device > +====================================== > + > +Introduction > +============ > + > +HiSilicon PCIe tune and trace device (PTT) is a PCIe Root Complex > +integrated Endpoint (RCiEP) device, providing the capability > +to dynamically monitor and tune the PCIe link's events (tune), > +and trace the TLP headers (trace). The two functions are independent, > +but is recommended to use them together to analyze and enhance the > +PCIe link's performance. > + > +On Kunpeng 930 SoC, the PCIe Root Complex is composed of several > +PCIe cores. Each PCIe core includes several Root Ports and a PTT > +RCiEP, like below. The PTT device is capable of tuning and > +tracing the link of the PCIe core. links > +:: > + +--------------Core 0-------+ > + | | [ PTT ] | > + | | [Root Port]---[Endpoint] > + | | [Root Port]---[Endpoint] > + | | [Root Port]---[Endpoint] > + Root Complex |------Core 1-------+ > + | | [ PTT ] | > + | | [Root Port]---[ Switch ]---[Endpoint] > + | | [Root Port]---[Endpoint] `-[Endpoint] > + | | [Root Port]---[Endpoint] > + +---------------------------+ > + > +The PTT device driver registers PMU device for each PTT device. registers one PMU device .. > +The name of each PTT device is composed of 'hisi_ptt' prefix with > +the id of the SICL and the Core where it locates. The Kunpeng 930 > +SoC encapsulates multiple CPU dies (SCCL, Super CPU Cluster) and > +IO dies (SICL, Super I/O Cluster), where there's one PCIe Root > +Complex for each SICL. > +:: > + /sys/devices/hisi_ptt<sicl_id>_<core_id> > + > +Tune > +==== > + > +PTT tune is designed for monitoring and adjusting PCIe link parameters (events). > +Currently we support events in 4 classes. The scope of the events > +covers the PCIe core to which the PTT device belongs. > + > +Each event is presented as a file under $(PTT PMU dir)/tune, and > +mostly a simple open/read/write/close cycle will be used to tune drop "mostly" as it doesn't add anything other than potential confusion. > +the event. > +:: > + $ cd /sys/devices/hisi_ptt<sicl_id>_<core_id>/tune > + $ ls > + qos_tx_cpl qos_tx_np qos_tx_p > + tx_path_rx_req_alloc_buf_level > + tx_path_tx_req_alloc_buf_level > + $ cat qos_tx_dp > + 1 > + $ echo 2 > qos_tx_dp > + $ cat qos_tx_dp > + 2 > + > +Current value (numerical value) of the event can be simply read > +from the file, and the desired value written to the file to tune. > + > +1. Tx path QoS control > +------------------------ > + > +The following files are provided to tune the QoS of the tx path of > +the PCIe core. > + > +- qos_tx_cpl: weight of Tx completion TLPs > +- qos_tx_np: weight of Tx non-posted TLPs > +- qos_tx_p: weight of Tx posted TLPs > + > +The weight influences the proportion of certain packets on the PCIe link. > +For example, for the storage scenario, increase the proportion > +of the completion packets on the link to enhance the performance as > +more completions are consumed. > + > +The available tune data of these events is [0, 1, 2]. > +Writing a negative value will return an error, and out of range > +values will be converted to 2. Note that the event value just > +indicates a probable level, but is not precise. > + > +2. Tx path buffer control > +------------------------- > + > +Following files are provided to tune the buffer of tx path of the PCIe core. > + > +- tx_path_rx_req_alloc_buf_level: watermark of Rx requested > +- tx_path_tx_req_alloc_buf_level: watermark of Tx requested > + > +These events influence the watermark of the buffer allocated for each > +type. Rx means the inbound while Tx means outbound. The packets will > +be stored in the buffer first and then posted either when the watermark Change "posted" to "transmitted" as posted has a special meaning in PCI and I don't think that is what you mean here... (I could be wrong!) > +reached or when timed out. For a busy direction, you should increase > +the related buffer watermark to avoid frequently posting and thus > +enhance the performance. In most cases just keep the default value. > + > +The available tune data of above events is [0, 1, 2]. > +Writing a negative value will return an error, and out of range > +values will be converted to 2. Note that the event value just > +indicates a probable level, but is not precise. > + > +Trace > +===== > + > +PTT trace is designed for dumping the TLP headers to the memory, which > +can be used to analyze the transactions and usage condition of the PCIe > +Link. You can choose to filter the traced headers by either requester ID, > +or those downstream of a set of Root Ports on the same core of the PTT > +device. It's also supported to trace the headers of certain type and of > +certain direction. > + > +You can use the perf command `perf record` to set the parameters, start > +trace and get the data. It's also supported to decode the trace > +data with `perf report`. The control parameters for trace is inputted > +as event code for each events, which will be further illustracted later. illustrated > +An example usage is like > +:: > + $ perf record -e hisi_ptt0_2/filter=0x80001,type=1,direction=1, > + format=1/ -- sleep 5 > + > +This will trace the TLP headers downstream root port 0000:00:10.1 (event > +code for event 'filter' is 0x80001) with type of posted TLP requests, > +direction of inbound and traced data format of 8DW. > + > +1. filter > +--------- > + > +The TLP headers to trace can be filtered by the Root Ports or the requester > +ID of the endpoints, which are locates on the same core of the PTT device. located > +You can set the filter by spedifying the `filter` parameter which is required > +to start the trace. The parameter value is 20 bit. The supported filters and > +related values is outputted through `available_filters` sysfs attribute > +under related PTT PMU directory, classified as Root Ports and Requesters > +respectively. > +:: > + $ cat available_filters > + #### Root Ports #### > + 0000:00:10.0 0x80001 > + 0000:00:11.0 0x80004 > + #### Requesters #### > + 0000:01:00.0 0x00100 > + 0000:01:00.1 0x00101 > + > +Note that multiple Root Ports can be specified at one time, but only > +one Endpoint function can be specified in one trace. Specifying both > +Root Port and function at the same time is not supported. > + > +If no filter is available, reading the available_filters will get the hint. > +:: > + $ cat available_filters > + #### No available filter #### If you take not of my earlier feedback this bit may change slightly. > + > +The available_filters can be dynamically updated, which means you can always > +get correct filter information when hotplug events happen, or when you manually > +remove/rescan the devices. > + > +2. type > +------- > + > +You can trace the TLP headers of certain types by specifying the `type` > +parameter, which is required to start the trace. The parameter value is > +8 bit. Current supported types and related values are shown below: > + > +8'b00000001: posted requests (P) > +8'b00000010: non-posted requests (NP) > +8'b00000100: completions (CPL) > + > +You can specify multiple types when tracing inbound TLP headers, but can only > +specify one when tracing outbound TLP headers. > + > +3. direction > +------------ > + > +You can trace the TLP headers from certain direction, which is relative > +to the Root Port or the PCIe core, by specifying the `direction` parameter. > +This is optional and the default parameter is inbound. The parameter value > +is 4 bit. When the desired format is 4DW, directions and related values > +supported are shown below: > + > +4'b0000: inbound TLPs (P, NP, CPL) > +4'b0001: outbound TLPs (P, NP, CPL) > +4'b0010: outbound TLPs (P, NP, CPL) and inbound TLPs (P, NP, CPL B) > +4'b0011: outbound TLPs (P, NP, CPL) and inbound TLPs (CPL A) > + > +When the desired format is 8DW, directions and related values supported are > +shown below: > + > +4'b0000: reserved > +4'b0001: outbound TLPs (P, NP, CPL) > +4'b0010: inbound TLPs (P, NP, CPL B) > +4'b0011: inbound TLPs (CPL A) > + > +Inbound completions are classifed into two types: classified > + > +completion A (CPL A): completion of CHI/DMA/Native non-posted requests, except for CPL B > +completion B (CPL B): completion of DMA remote2local and P2P non-posted requests > + > +4. format > +-------------- > + > +You can change the format of the traced TLP headers by specifying the > +`format` parameter. This is optional and the default format is 4DW. As there is a default, there is no need to also say it is optional. `format parameter. The default format is 4DW. > +The parameter value is 4 bit. Current supported formats and related > +values are shown below: > + > +4'b0000: 4DW length per TLP header > +4'b0001: 8DW length per TLP header > + > +The traced TLP header format is different from the PCIe standard. > + > +When using the 8DW data format, the entire TLP header is logged > +(Header DW0-3 shown below). For example, the TLP header for Memory > +Reads with 64-bit addresses is shown in PCIe r5.0, Figure 2-17; > +the header for Configuration Requests is shown in Figure 2.20, etc. > + > +In addition, 8DW trace buffer entries contain a timestamp and > +possibly a prefix for a PASID TLP prefix (see Figure 6-20, PCIe r5.0). > +Otherwise this field will be all 0. > + > +The bit[31:11] of DW0 is always 0x1fffff, which can be > +used to distinguish the data format. 8DW format is like > +:: > + bits [ 31:11 ][ 10:0 ] > + |---------------------------------------|-------------------| > + DW0 [ 0x1fffff ][ Reserved (0x7ff) ] > + DW1 [ Prefix ] > + DW2 [ Header DW0 ] > + DW3 [ Header DW1 ] > + DW4 [ Header DW2 ] > + DW5 [ Header DW3 ] > + DW6 [ Reserved (0x0) ] > + DW7 [ Time ] > + > +When using the 4DW data format, DW0 of the trace buffer entry > +contains selected fields of DW0 of the TLP, together with a > +timestamp. DW1-DW3 of the trace buffer entry contain DW1-DW3 > +directly from the TLP header. > + > +4DW format is like > +:: > + bits [31:30] [ 29:25 ][24][23][22][21][ 20:11 ][ 10:0 ] > + |-----|---------|---|---|---|---|-------------|-------------| > + DW0 [ Fmt ][ Type ][T9][T8][TH][SO][ Length ][ Time ] > + DW1 [ Header DW1 ] > + DW2 [ Header DW2 ] > + DW3 [ Header DW3 ] > + > +5. memory management > +-------------------- > + > +The traced TLP headers will be written to the memory allocated > +by the driver. The hardware accepts 4 DMA address with same size, > +and writes the buffer sequentially like below. If DMA addr 3 is > +finished and the trace is still on, it will return to addr 0. > +:: > + +->[DMA addr 0]->[DMA addr 1]->[DMA addr 2]->[DMA addr 3]-+ > + +---------------------------------------------------------+ > + > +Driver will allocate each DMA buffer of 4MiB. The finished buffer > +will be copied to the perf AUX buffer allocated by the perf core. > +Once the AUX buffer is full while the trace is still on, driver > +will commit the AUX buffer first and then apply for a new one with > +the same size. The size of AUX buffer is default to 16MiB. User can > +adjust the size by specifying the `-m` parameter of the perf command. > + > +Note that there is a gap between committing the old AUX buffer and > +applying a new one, which means the trace is stopped during the > +moment and TLPs transferred in the moment cannot be traced. To avoid > +this situation, you should begin the trace with large AUX buffer > +enough to avoid this gap. > + > +6. decoding > +----------- > + > +You can decode the traced data with `perf report -D` command (currently > +only support to dump the raw trace data). The traced data will be decoded > +according to the format described previously (take 8DW as an example): > +:: > + [...perf headers and other information] > + . ... HISI PTT data: size 4194304 bytes > + . 00000000: 00 00 00 00 Prefix > + . 00000004: 01 00 00 60 Header DW0 > + . 00000008: 0f 1e 00 01 Header DW1 > + . 0000000c: 04 00 00 00 Header DW2 > + . 00000010: 40 00 81 02 Header DW3 > + . 00000014: 33 c0 04 00 Time > + . 00000020: 00 00 00 00 Prefix > + . 00000024: 01 00 00 60 Header DW0 > + . 00000028: 0f 1e 00 01 Header DW1 > + . 0000002c: 04 00 00 00 Header DW2 > + . 00000030: 40 00 81 02 Header DW3 > + . 00000034: 02 00 00 00 Time > + . 00000040: 00 00 00 00 Prefix > + . 00000044: 01 00 00 60 Header DW0 > + . 00000048: 0f 1e 00 01 Header DW1 > + . 0000004c: 04 00 00 00 Header DW2 > + . 00000050: 40 00 81 02 Header DW3 > + [...]
On 2022/2/7 20:12, Jonathan Cameron wrote: > On Mon, 24 Jan 2022 21:11:16 +0800 > Yicong Yang <yangyicong@hisilicon.com> wrote: > >> Document the introduction and usage of HiSilicon PTT device driver. >> >> Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> > Nice document. A few trivial typos inline. > I would give a RB except I've suggested you change a part of the > sysfs interface which will affect the relevant documentation. > Thanks. I'll get these fixed and update the documentation with sysfs interface updated. > Thanks, > > Jonathan > >> --- >> Documentation/trace/hisi-ptt.rst | 304 +++++++++++++++++++++++++++++++ >> 1 file changed, 304 insertions(+) >> create mode 100644 Documentation/trace/hisi-ptt.rst >> >> diff --git a/Documentation/trace/hisi-ptt.rst b/Documentation/trace/hisi-ptt.rst >> new file mode 100644 >> index 000000000000..f3269b11a2f6 >> --- /dev/null >> +++ b/Documentation/trace/hisi-ptt.rst >> @@ -0,0 +1,304 @@ >> +.. SPDX-License-Identifier: GPL-2.0 >> + >> +====================================== >> +HiSilicon PCIe Tune and Trace device >> +====================================== >> + >> +Introduction >> +============ >> + >> +HiSilicon PCIe tune and trace device (PTT) is a PCIe Root Complex >> +integrated Endpoint (RCiEP) device, providing the capability >> +to dynamically monitor and tune the PCIe link's events (tune), >> +and trace the TLP headers (trace). The two functions are independent, >> +but is recommended to use them together to analyze and enhance the >> +PCIe link's performance. >> + >> +On Kunpeng 930 SoC, the PCIe Root Complex is composed of several >> +PCIe cores. Each PCIe core includes several Root Ports and a PTT >> +RCiEP, like below. The PTT device is capable of tuning and >> +tracing the link of the PCIe core. > > links > >> +:: >> + +--------------Core 0-------+ >> + | | [ PTT ] | >> + | | [Root Port]---[Endpoint] >> + | | [Root Port]---[Endpoint] >> + | | [Root Port]---[Endpoint] >> + Root Complex |------Core 1-------+ >> + | | [ PTT ] | >> + | | [Root Port]---[ Switch ]---[Endpoint] >> + | | [Root Port]---[Endpoint] `-[Endpoint] >> + | | [Root Port]---[Endpoint] >> + +---------------------------+ >> + >> +The PTT device driver registers PMU device for each PTT device. > > registers one PMU device .. > >> +The name of each PTT device is composed of 'hisi_ptt' prefix with >> +the id of the SICL and the Core where it locates. The Kunpeng 930 >> +SoC encapsulates multiple CPU dies (SCCL, Super CPU Cluster) and >> +IO dies (SICL, Super I/O Cluster), where there's one PCIe Root >> +Complex for each SICL. >> +:: >> + /sys/devices/hisi_ptt<sicl_id>_<core_id> >> + >> +Tune >> +==== >> + >> +PTT tune is designed for monitoring and adjusting PCIe link parameters (events). >> +Currently we support events in 4 classes. The scope of the events >> +covers the PCIe core to which the PTT device belongs. >> + >> +Each event is presented as a file under $(PTT PMU dir)/tune, and >> +mostly a simple open/read/write/close cycle will be used to tune > > drop "mostly" as it doesn't add anything other than potential confusion. > >> +the event. >> +:: >> + $ cd /sys/devices/hisi_ptt<sicl_id>_<core_id>/tune >> + $ ls >> + qos_tx_cpl qos_tx_np qos_tx_p >> + tx_path_rx_req_alloc_buf_level >> + tx_path_tx_req_alloc_buf_level >> + $ cat qos_tx_dp >> + 1 >> + $ echo 2 > qos_tx_dp >> + $ cat qos_tx_dp >> + 2 >> + >> +Current value (numerical value) of the event can be simply read >> +from the file, and the desired value written to the file to tune. >> + >> +1. Tx path QoS control >> +------------------------ >> + >> +The following files are provided to tune the QoS of the tx path of >> +the PCIe core. >> + >> +- qos_tx_cpl: weight of Tx completion TLPs >> +- qos_tx_np: weight of Tx non-posted TLPs >> +- qos_tx_p: weight of Tx posted TLPs >> + >> +The weight influences the proportion of certain packets on the PCIe link. >> +For example, for the storage scenario, increase the proportion >> +of the completion packets on the link to enhance the performance as >> +more completions are consumed. >> + >> +The available tune data of these events is [0, 1, 2]. >> +Writing a negative value will return an error, and out of range >> +values will be converted to 2. Note that the event value just >> +indicates a probable level, but is not precise. >> + >> +2. Tx path buffer control >> +------------------------- >> + >> +Following files are provided to tune the buffer of tx path of the PCIe core. >> + >> +- tx_path_rx_req_alloc_buf_level: watermark of Rx requested >> +- tx_path_tx_req_alloc_buf_level: watermark of Tx requested >> + >> +These events influence the watermark of the buffer allocated for each >> +type. Rx means the inbound while Tx means outbound. The packets will >> +be stored in the buffer first and then posted either when the watermark > > Change "posted" to "transmitted" as posted has a special meaning in PCI > and I don't think that is what you mean here... (I could be wrong!) > >> +reached or when timed out. For a busy direction, you should increase >> +the related buffer watermark to avoid frequently posting and thus >> +enhance the performance. In most cases just keep the default value. >> + >> +The available tune data of above events is [0, 1, 2]. >> +Writing a negative value will return an error, and out of range >> +values will be converted to 2. Note that the event value just >> +indicates a probable level, but is not precise. >> + >> +Trace >> +===== >> + >> +PTT trace is designed for dumping the TLP headers to the memory, which >> +can be used to analyze the transactions and usage condition of the PCIe >> +Link. You can choose to filter the traced headers by either requester ID, >> +or those downstream of a set of Root Ports on the same core of the PTT >> +device. It's also supported to trace the headers of certain type and of >> +certain direction. >> + >> +You can use the perf command `perf record` to set the parameters, start >> +trace and get the data. It's also supported to decode the trace >> +data with `perf report`. The control parameters for trace is inputted >> +as event code for each events, which will be further illustracted later. > > illustrated > >> +An example usage is like >> +:: >> + $ perf record -e hisi_ptt0_2/filter=0x80001,type=1,direction=1, >> + format=1/ -- sleep 5 >> + >> +This will trace the TLP headers downstream root port 0000:00:10.1 (event >> +code for event 'filter' is 0x80001) with type of posted TLP requests, >> +direction of inbound and traced data format of 8DW. >> + >> +1. filter >> +--------- >> + >> +The TLP headers to trace can be filtered by the Root Ports or the requester >> +ID of the endpoints, which are locates on the same core of the PTT device. > > located > >> +You can set the filter by spedifying the `filter` parameter which is required >> +to start the trace. The parameter value is 20 bit. The supported filters and >> +related values is outputted through `available_filters` sysfs attribute >> +under related PTT PMU directory, classified as Root Ports and Requesters >> +respectively. >> +:: >> + $ cat available_filters >> + #### Root Ports #### >> + 0000:00:10.0 0x80001 >> + 0000:00:11.0 0x80004 >> + #### Requesters #### >> + 0000:01:00.0 0x00100 >> + 0000:01:00.1 0x00101 >> + >> +Note that multiple Root Ports can be specified at one time, but only >> +one Endpoint function can be specified in one trace. Specifying both >> +Root Port and function at the same time is not supported. >> + >> +If no filter is available, reading the available_filters will get the hint. >> +:: >> + $ cat available_filters >> + #### No available filter #### > > If you take not of my earlier feedback this bit may change slightly. >> + >> +The available_filters can be dynamically updated, which means you can always >> +get correct filter information when hotplug events happen, or when you manually >> +remove/rescan the devices. >> + >> +2. type >> +------- >> + >> +You can trace the TLP headers of certain types by specifying the `type` >> +parameter, which is required to start the trace. The parameter value is >> +8 bit. Current supported types and related values are shown below: >> + >> +8'b00000001: posted requests (P) >> +8'b00000010: non-posted requests (NP) >> +8'b00000100: completions (CPL) >> + >> +You can specify multiple types when tracing inbound TLP headers, but can only >> +specify one when tracing outbound TLP headers. >> + >> +3. direction >> +------------ >> + >> +You can trace the TLP headers from certain direction, which is relative >> +to the Root Port or the PCIe core, by specifying the `direction` parameter. >> +This is optional and the default parameter is inbound. The parameter value >> +is 4 bit. When the desired format is 4DW, directions and related values >> +supported are shown below: >> + >> +4'b0000: inbound TLPs (P, NP, CPL) >> +4'b0001: outbound TLPs (P, NP, CPL) >> +4'b0010: outbound TLPs (P, NP, CPL) and inbound TLPs (P, NP, CPL B) >> +4'b0011: outbound TLPs (P, NP, CPL) and inbound TLPs (CPL A) >> + >> +When the desired format is 8DW, directions and related values supported are >> +shown below: >> + >> +4'b0000: reserved >> +4'b0001: outbound TLPs (P, NP, CPL) >> +4'b0010: inbound TLPs (P, NP, CPL B) >> +4'b0011: inbound TLPs (CPL A) >> + >> +Inbound completions are classifed into two types: > > classified > >> + >> +completion A (CPL A): completion of CHI/DMA/Native non-posted requests, except for CPL B >> +completion B (CPL B): completion of DMA remote2local and P2P non-posted requests >> + >> +4. format >> +-------------- >> + >> +You can change the format of the traced TLP headers by specifying the >> +`format` parameter. This is optional and the default format is 4DW. > > As there is a default, there is no need to also say it is optional. > `format parameter. The default format is 4DW. > >> +The parameter value is 4 bit. Current supported formats and related >> +values are shown below: >> + >> +4'b0000: 4DW length per TLP header >> +4'b0001: 8DW length per TLP header >> + >> +The traced TLP header format is different from the PCIe standard. >> + >> +When using the 8DW data format, the entire TLP header is logged >> +(Header DW0-3 shown below). For example, the TLP header for Memory >> +Reads with 64-bit addresses is shown in PCIe r5.0, Figure 2-17; >> +the header for Configuration Requests is shown in Figure 2.20, etc. >> + >> +In addition, 8DW trace buffer entries contain a timestamp and >> +possibly a prefix for a PASID TLP prefix (see Figure 6-20, PCIe r5.0). >> +Otherwise this field will be all 0. >> + >> +The bit[31:11] of DW0 is always 0x1fffff, which can be >> +used to distinguish the data format. 8DW format is like >> +:: >> + bits [ 31:11 ][ 10:0 ] >> + |---------------------------------------|-------------------| >> + DW0 [ 0x1fffff ][ Reserved (0x7ff) ] >> + DW1 [ Prefix ] >> + DW2 [ Header DW0 ] >> + DW3 [ Header DW1 ] >> + DW4 [ Header DW2 ] >> + DW5 [ Header DW3 ] >> + DW6 [ Reserved (0x0) ] >> + DW7 [ Time ] >> + >> +When using the 4DW data format, DW0 of the trace buffer entry >> +contains selected fields of DW0 of the TLP, together with a >> +timestamp. DW1-DW3 of the trace buffer entry contain DW1-DW3 >> +directly from the TLP header. >> + >> +4DW format is like >> +:: >> + bits [31:30] [ 29:25 ][24][23][22][21][ 20:11 ][ 10:0 ] >> + |-----|---------|---|---|---|---|-------------|-------------| >> + DW0 [ Fmt ][ Type ][T9][T8][TH][SO][ Length ][ Time ] >> + DW1 [ Header DW1 ] >> + DW2 [ Header DW2 ] >> + DW3 [ Header DW3 ] >> + >> +5. memory management >> +-------------------- >> + >> +The traced TLP headers will be written to the memory allocated >> +by the driver. The hardware accepts 4 DMA address with same size, >> +and writes the buffer sequentially like below. If DMA addr 3 is >> +finished and the trace is still on, it will return to addr 0. >> +:: >> + +->[DMA addr 0]->[DMA addr 1]->[DMA addr 2]->[DMA addr 3]-+ >> + +---------------------------------------------------------+ >> + >> +Driver will allocate each DMA buffer of 4MiB. The finished buffer >> +will be copied to the perf AUX buffer allocated by the perf core. >> +Once the AUX buffer is full while the trace is still on, driver >> +will commit the AUX buffer first and then apply for a new one with >> +the same size. The size of AUX buffer is default to 16MiB. User can >> +adjust the size by specifying the `-m` parameter of the perf command. >> + >> +Note that there is a gap between committing the old AUX buffer and >> +applying a new one, which means the trace is stopped during the >> +moment and TLPs transferred in the moment cannot be traced. To avoid >> +this situation, you should begin the trace with large AUX buffer >> +enough to avoid this gap. >> + >> +6. decoding >> +----------- >> + >> +You can decode the traced data with `perf report -D` command (currently >> +only support to dump the raw trace data). The traced data will be decoded >> +according to the format described previously (take 8DW as an example): >> +:: >> + [...perf headers and other information] >> + . ... HISI PTT data: size 4194304 bytes >> + . 00000000: 00 00 00 00 Prefix >> + . 00000004: 01 00 00 60 Header DW0 >> + . 00000008: 0f 1e 00 01 Header DW1 >> + . 0000000c: 04 00 00 00 Header DW2 >> + . 00000010: 40 00 81 02 Header DW3 >> + . 00000014: 33 c0 04 00 Time >> + . 00000020: 00 00 00 00 Prefix >> + . 00000024: 01 00 00 60 Header DW0 >> + . 00000028: 0f 1e 00 01 Header DW1 >> + . 0000002c: 04 00 00 00 Header DW2 >> + . 00000030: 40 00 81 02 Header DW3 >> + . 00000034: 02 00 00 00 Time >> + . 00000040: 00 00 00 00 Prefix >> + . 00000044: 01 00 00 60 Header DW0 >> + . 00000048: 0f 1e 00 01 Header DW1 >> + . 0000004c: 04 00 00 00 Header DW2 >> + . 00000050: 40 00 81 02 Header DW3 >> + [...] > > . >
diff --git a/Documentation/trace/hisi-ptt.rst b/Documentation/trace/hisi-ptt.rst new file mode 100644 index 000000000000..f3269b11a2f6 --- /dev/null +++ b/Documentation/trace/hisi-ptt.rst @@ -0,0 +1,304 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================================== +HiSilicon PCIe Tune and Trace device +====================================== + +Introduction +============ + +HiSilicon PCIe tune and trace device (PTT) is a PCIe Root Complex +integrated Endpoint (RCiEP) device, providing the capability +to dynamically monitor and tune the PCIe link's events (tune), +and trace the TLP headers (trace). The two functions are independent, +but is recommended to use them together to analyze and enhance the +PCIe link's performance. + +On Kunpeng 930 SoC, the PCIe Root Complex is composed of several +PCIe cores. Each PCIe core includes several Root Ports and a PTT +RCiEP, like below. The PTT device is capable of tuning and +tracing the link of the PCIe core. +:: + +--------------Core 0-------+ + | | [ PTT ] | + | | [Root Port]---[Endpoint] + | | [Root Port]---[Endpoint] + | | [Root Port]---[Endpoint] + Root Complex |------Core 1-------+ + | | [ PTT ] | + | | [Root Port]---[ Switch ]---[Endpoint] + | | [Root Port]---[Endpoint] `-[Endpoint] + | | [Root Port]---[Endpoint] + +---------------------------+ + +The PTT device driver registers PMU device for each PTT device. +The name of each PTT device is composed of 'hisi_ptt' prefix with +the id of the SICL and the Core where it locates. The Kunpeng 930 +SoC encapsulates multiple CPU dies (SCCL, Super CPU Cluster) and +IO dies (SICL, Super I/O Cluster), where there's one PCIe Root +Complex for each SICL. +:: + /sys/devices/hisi_ptt<sicl_id>_<core_id> + +Tune +==== + +PTT tune is designed for monitoring and adjusting PCIe link parameters (events). +Currently we support events in 4 classes. The scope of the events +covers the PCIe core to which the PTT device belongs. + +Each event is presented as a file under $(PTT PMU dir)/tune, and +mostly a simple open/read/write/close cycle will be used to tune +the event. +:: + $ cd /sys/devices/hisi_ptt<sicl_id>_<core_id>/tune + $ ls + qos_tx_cpl qos_tx_np qos_tx_p + tx_path_rx_req_alloc_buf_level + tx_path_tx_req_alloc_buf_level + $ cat qos_tx_dp + 1 + $ echo 2 > qos_tx_dp + $ cat qos_tx_dp + 2 + +Current value (numerical value) of the event can be simply read +from the file, and the desired value written to the file to tune. + +1. Tx path QoS control +------------------------ + +The following files are provided to tune the QoS of the tx path of +the PCIe core. + +- qos_tx_cpl: weight of Tx completion TLPs +- qos_tx_np: weight of Tx non-posted TLPs +- qos_tx_p: weight of Tx posted TLPs + +The weight influences the proportion of certain packets on the PCIe link. +For example, for the storage scenario, increase the proportion +of the completion packets on the link to enhance the performance as +more completions are consumed. + +The available tune data of these events is [0, 1, 2]. +Writing a negative value will return an error, and out of range +values will be converted to 2. Note that the event value just +indicates a probable level, but is not precise. + +2. Tx path buffer control +------------------------- + +Following files are provided to tune the buffer of tx path of the PCIe core. + +- tx_path_rx_req_alloc_buf_level: watermark of Rx requested +- tx_path_tx_req_alloc_buf_level: watermark of Tx requested + +These events influence the watermark of the buffer allocated for each +type. Rx means the inbound while Tx means outbound. The packets will +be stored in the buffer first and then posted either when the watermark +reached or when timed out. For a busy direction, you should increase +the related buffer watermark to avoid frequently posting and thus +enhance the performance. In most cases just keep the default value. + +The available tune data of above events is [0, 1, 2]. +Writing a negative value will return an error, and out of range +values will be converted to 2. Note that the event value just +indicates a probable level, but is not precise. + +Trace +===== + +PTT trace is designed for dumping the TLP headers to the memory, which +can be used to analyze the transactions and usage condition of the PCIe +Link. You can choose to filter the traced headers by either requester ID, +or those downstream of a set of Root Ports on the same core of the PTT +device. It's also supported to trace the headers of certain type and of +certain direction. + +You can use the perf command `perf record` to set the parameters, start +trace and get the data. It's also supported to decode the trace +data with `perf report`. The control parameters for trace is inputted +as event code for each events, which will be further illustracted later. +An example usage is like +:: + $ perf record -e hisi_ptt0_2/filter=0x80001,type=1,direction=1, + format=1/ -- sleep 5 + +This will trace the TLP headers downstream root port 0000:00:10.1 (event +code for event 'filter' is 0x80001) with type of posted TLP requests, +direction of inbound and traced data format of 8DW. + +1. filter +--------- + +The TLP headers to trace can be filtered by the Root Ports or the requester +ID of the endpoints, which are locates on the same core of the PTT device. +You can set the filter by spedifying the `filter` parameter which is required +to start the trace. The parameter value is 20 bit. The supported filters and +related values is outputted through `available_filters` sysfs attribute +under related PTT PMU directory, classified as Root Ports and Requesters +respectively. +:: + $ cat available_filters + #### Root Ports #### + 0000:00:10.0 0x80001 + 0000:00:11.0 0x80004 + #### Requesters #### + 0000:01:00.0 0x00100 + 0000:01:00.1 0x00101 + +Note that multiple Root Ports can be specified at one time, but only +one Endpoint function can be specified in one trace. Specifying both +Root Port and function at the same time is not supported. + +If no filter is available, reading the available_filters will get the hint. +:: + $ cat available_filters + #### No available filter #### + +The available_filters can be dynamically updated, which means you can always +get correct filter information when hotplug events happen, or when you manually +remove/rescan the devices. + +2. type +------- + +You can trace the TLP headers of certain types by specifying the `type` +parameter, which is required to start the trace. The parameter value is +8 bit. Current supported types and related values are shown below: + +8'b00000001: posted requests (P) +8'b00000010: non-posted requests (NP) +8'b00000100: completions (CPL) + +You can specify multiple types when tracing inbound TLP headers, but can only +specify one when tracing outbound TLP headers. + +3. direction +------------ + +You can trace the TLP headers from certain direction, which is relative +to the Root Port or the PCIe core, by specifying the `direction` parameter. +This is optional and the default parameter is inbound. The parameter value +is 4 bit. When the desired format is 4DW, directions and related values +supported are shown below: + +4'b0000: inbound TLPs (P, NP, CPL) +4'b0001: outbound TLPs (P, NP, CPL) +4'b0010: outbound TLPs (P, NP, CPL) and inbound TLPs (P, NP, CPL B) +4'b0011: outbound TLPs (P, NP, CPL) and inbound TLPs (CPL A) + +When the desired format is 8DW, directions and related values supported are +shown below: + +4'b0000: reserved +4'b0001: outbound TLPs (P, NP, CPL) +4'b0010: inbound TLPs (P, NP, CPL B) +4'b0011: inbound TLPs (CPL A) + +Inbound completions are classifed into two types: + +completion A (CPL A): completion of CHI/DMA/Native non-posted requests, except for CPL B +completion B (CPL B): completion of DMA remote2local and P2P non-posted requests + +4. format +-------------- + +You can change the format of the traced TLP headers by specifying the +`format` parameter. This is optional and the default format is 4DW. +The parameter value is 4 bit. Current supported formats and related +values are shown below: + +4'b0000: 4DW length per TLP header +4'b0001: 8DW length per TLP header + +The traced TLP header format is different from the PCIe standard. + +When using the 8DW data format, the entire TLP header is logged +(Header DW0-3 shown below). For example, the TLP header for Memory +Reads with 64-bit addresses is shown in PCIe r5.0, Figure 2-17; +the header for Configuration Requests is shown in Figure 2.20, etc. + +In addition, 8DW trace buffer entries contain a timestamp and +possibly a prefix for a PASID TLP prefix (see Figure 6-20, PCIe r5.0). +Otherwise this field will be all 0. + +The bit[31:11] of DW0 is always 0x1fffff, which can be +used to distinguish the data format. 8DW format is like +:: + bits [ 31:11 ][ 10:0 ] + |---------------------------------------|-------------------| + DW0 [ 0x1fffff ][ Reserved (0x7ff) ] + DW1 [ Prefix ] + DW2 [ Header DW0 ] + DW3 [ Header DW1 ] + DW4 [ Header DW2 ] + DW5 [ Header DW3 ] + DW6 [ Reserved (0x0) ] + DW7 [ Time ] + +When using the 4DW data format, DW0 of the trace buffer entry +contains selected fields of DW0 of the TLP, together with a +timestamp. DW1-DW3 of the trace buffer entry contain DW1-DW3 +directly from the TLP header. + +4DW format is like +:: + bits [31:30] [ 29:25 ][24][23][22][21][ 20:11 ][ 10:0 ] + |-----|---------|---|---|---|---|-------------|-------------| + DW0 [ Fmt ][ Type ][T9][T8][TH][SO][ Length ][ Time ] + DW1 [ Header DW1 ] + DW2 [ Header DW2 ] + DW3 [ Header DW3 ] + +5. memory management +-------------------- + +The traced TLP headers will be written to the memory allocated +by the driver. The hardware accepts 4 DMA address with same size, +and writes the buffer sequentially like below. If DMA addr 3 is +finished and the trace is still on, it will return to addr 0. +:: + +->[DMA addr 0]->[DMA addr 1]->[DMA addr 2]->[DMA addr 3]-+ + +---------------------------------------------------------+ + +Driver will allocate each DMA buffer of 4MiB. The finished buffer +will be copied to the perf AUX buffer allocated by the perf core. +Once the AUX buffer is full while the trace is still on, driver +will commit the AUX buffer first and then apply for a new one with +the same size. The size of AUX buffer is default to 16MiB. User can +adjust the size by specifying the `-m` parameter of the perf command. + +Note that there is a gap between committing the old AUX buffer and +applying a new one, which means the trace is stopped during the +moment and TLPs transferred in the moment cannot be traced. To avoid +this situation, you should begin the trace with large AUX buffer +enough to avoid this gap. + +6. decoding +----------- + +You can decode the traced data with `perf report -D` command (currently +only support to dump the raw trace data). The traced data will be decoded +according to the format described previously (take 8DW as an example): +:: + [...perf headers and other information] + . ... HISI PTT data: size 4194304 bytes + . 00000000: 00 00 00 00 Prefix + . 00000004: 01 00 00 60 Header DW0 + . 00000008: 0f 1e 00 01 Header DW1 + . 0000000c: 04 00 00 00 Header DW2 + . 00000010: 40 00 81 02 Header DW3 + . 00000014: 33 c0 04 00 Time + . 00000020: 00 00 00 00 Prefix + . 00000024: 01 00 00 60 Header DW0 + . 00000028: 0f 1e 00 01 Header DW1 + . 0000002c: 04 00 00 00 Header DW2 + . 00000030: 40 00 81 02 Header DW3 + . 00000034: 02 00 00 00 Time + . 00000040: 00 00 00 00 Prefix + . 00000044: 01 00 00 60 Header DW0 + . 00000048: 0f 1e 00 01 Header DW1 + . 0000004c: 04 00 00 00 Header DW2 + . 00000050: 40 00 81 02 Header DW3 + [...]
Document the introduction and usage of HiSilicon PTT device driver. Signed-off-by: Yicong Yang <yangyicong@hisilicon.com> --- Documentation/trace/hisi-ptt.rst | 304 +++++++++++++++++++++++++++++++ 1 file changed, 304 insertions(+) create mode 100644 Documentation/trace/hisi-ptt.rst