| Message ID | 152244391852.135666.14903825998610307052.stgit@bhelgaas-glaptop.roam.corp.google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
> -----Original Message----- > From: Bjorn Helgaas [mailto:helgaas@kernel.org] > Sent: Friday, March 30, 2018 2:05 PM > To: Tal Gilboa <talgi@mellanox.com> > Cc: Tariq Toukan <tariqt@mellanox.com>; Keller, Jacob E > <jacob.e.keller@intel.com>; Ariel Elior <ariel.elior@cavium.com>; Ganesh > Goudar <ganeshgr@chelsio.com>; Kirsher, Jeffrey T > <jeffrey.t.kirsher@intel.com>; everest-linux-l2@cavium.com; intel-wired- > lan@lists.osuosl.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-pci@vger.kernel.org > Subject: [PATCH v5 05/14] PCI: Add pcie_print_link_status() to log link speed and > whether it's limited > > From: Tal Gilboa <talgi@mellanox.com> > > Add pcie_print_link_status(). This logs the current settings of the link > (speed, width, and total available bandwidth). > > If the device is capable of more bandwidth but is limited by a slower > upstream link, we include information about the link that limits the > device's performance. > > The user may be able to move the device to a different slot for better > performance. > > This provides a unified method for all PCI devices to report status and > issues, instead of each device reporting in a different way, using > different code. > > Signed-off-by: Tal Gilboa <talgi@mellanox.com> > [bhelgaas: changelog, reword log messages, print device capabilities when > not limited] > Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> > --- > drivers/pci/pci.c | 29 +++++++++++++++++++++++++++++ > include/linux/pci.h | 1 + > 2 files changed, 30 insertions(+) > > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c > index e00d56b12747..cec7aed09f6b 100644 > --- a/drivers/pci/pci.c > +++ b/drivers/pci/pci.c > @@ -5283,6 +5283,35 @@ u32 pcie_bandwidth_capable(struct pci_dev *dev, > enum pci_bus_speed *speed, > return *width * PCIE_SPEED2MBS_ENC(*speed); > } > > +/** > + * pcie_print_link_status - Report the PCI device's link speed and width > + * @dev: PCI device to query > + * > + * Report the available bandwidth at the device. If this is less than the > + * device is capable of, report the device's maximum possible bandwidth and > + * the upstream link that limits its performance to less than that. > + */ > +void pcie_print_link_status(struct pci_dev *dev) > +{ > + enum pcie_link_width width, width_cap; > + enum pci_bus_speed speed, speed_cap; > + struct pci_dev *limiting_dev = NULL; > + u32 bw_avail, bw_cap; > + > + bw_cap = pcie_bandwidth_capable(dev, &speed_cap, &width_cap); > + bw_avail = pcie_bandwidth_available(dev, &limiting_dev, &speed, > &width); > + > + if (bw_avail >= bw_cap) > + pci_info(dev, "%d Mb/s available bandwidth (%s x%d link)\n", > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); > + else > + pci_info(dev, "%d Mb/s available bandwidth, limited by %s x%d > link at %s (capable of %d Mb/s with %s x%d link)\n", > + bw_avail, PCIE_SPEED2STR(speed), width, > + limiting_dev ? pci_name(limiting_dev) : "<unknown>", > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); > +} Personally, I would make thic last one a pci_warn() to indicate it at a higher log level, but I'm ok with the wording, and if consensus is that this should be at info, I'm ok with that. Thanks, Jake > +EXPORT_SYMBOL(pcie_print_link_status); > + > /** > * pci_select_bars - Make BAR mask from the type of resource > * @dev: the PCI device for which BAR mask is made > diff --git a/include/linux/pci.h b/include/linux/pci.h > index f2bf2b7a66c7..38f7957121ef 100644 > --- a/include/linux/pci.h > +++ b/include/linux/pci.h > @@ -1086,6 +1086,7 @@ int pcie_get_minimum_link(struct pci_dev *dev, enum > pci_bus_speed *speed, > u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev > **limiting_dev, > enum pci_bus_speed *speed, > enum pcie_link_width *width); > +void pcie_print_link_status(struct pci_dev *dev); > void pcie_flr(struct pci_dev *dev); > int __pci_reset_function_locked(struct pci_dev *dev); > int pci_reset_function(struct pci_dev *dev);
On Fri, 30 Mar 2018 16:05:18 -0500, Bjorn Helgaas wrote: > + if (bw_avail >= bw_cap) > + pci_info(dev, "%d Mb/s available bandwidth (%s x%d link)\n", > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); > + else > + pci_info(dev, "%d Mb/s available bandwidth, limited by %s x%d link at %s (capable of %d Mb/s with %s x%d link)\n", > + bw_avail, PCIE_SPEED2STR(speed), width, > + limiting_dev ? pci_name(limiting_dev) : "<unknown>", > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); I was just looking at using this new function to print PCIe BW for a NIC, but I'm slightly worried that there is nothing in the message that says PCIe... For a NIC some people may interpret the bandwidth as NIC bandwidth: [ 39.839989] nfp 0000:04:00.0: Netronome Flow Processor NFP4000/NFP6000 PCIe Card Probe [ 39.848943] nfp 0000:04:00.0: 63.008 Gb/s available bandwidth (8 GT/s x8 link) [ 39.857146] nfp 0000:04:00.0: RESERVED BARs: 0.0: General/MSI-X SRAM, 0.1: PCIe XPB/MSI-X PBA, 0.4: Explicit0, 0.5: Explicit1, fre4 It's not a 63Gbps NIC... I'm sorry if this was discussed before and I didn't find it. Would it make sense to add the "PCIe: " prefix to the message like bnx2x used to do? Like: nfp 0000:04:00.0: PCIe: 63.008 Gb/s available bandwidth (8 GT/s x8 link) Sorry for a very late comment.
On Thu, Apr 12, 2018 at 09:32:49PM -0700, Jakub Kicinski wrote: > On Fri, 30 Mar 2018 16:05:18 -0500, Bjorn Helgaas wrote: > > + if (bw_avail >= bw_cap) > > + pci_info(dev, "%d Mb/s available bandwidth (%s x%d link)\n", > > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); > > + else > > + pci_info(dev, "%d Mb/s available bandwidth, limited by %s x%d link at %s (capable of %d Mb/s with %s x%d link)\n", > > + bw_avail, PCIE_SPEED2STR(speed), width, > > + limiting_dev ? pci_name(limiting_dev) : "<unknown>", > > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); > > I was just looking at using this new function to print PCIe BW for a > NIC, but I'm slightly worried that there is nothing in the message that > says PCIe... For a NIC some people may interpret the bandwidth as NIC > bandwidth: > > [ 39.839989] nfp 0000:04:00.0: Netronome Flow Processor NFP4000/NFP6000 PCIe Card Probe > [ 39.848943] nfp 0000:04:00.0: 63.008 Gb/s available bandwidth (8 GT/s x8 link) > [ 39.857146] nfp 0000:04:00.0: RESERVED BARs: 0.0: General/MSI-X SRAM, 0.1: PCIe XPB/MSI-X PBA, 0.4: Explicit0, 0.5: Explicit1, fre4 > > It's not a 63Gbps NIC... I'm sorry if this was discussed before and I > didn't find it. Would it make sense to add the "PCIe: " prefix to the > message like bnx2x used to do? Like: > > nfp 0000:04:00.0: PCIe: 63.008 Gb/s available bandwidth (8 GT/s x8 link) I agree, that does look potentially confusing. How about this: nfp 0000:04:00.0: 63.008 Gb/s available PCIe bandwidth (8 GT/s x8 link) I did have to look twice at this before I remembered that we're printing Gb/s (not GB/s). Most of the references I found on the web use GB/s when talking about total PCIe bandwidth. But either way I think it's definitely worth mentioning PCIe explicitly.
> -----Original Message----- > From: Bjorn Helgaas [mailto:helgaas@kernel.org] > Sent: Friday, April 13, 2018 7:07 AM > To: Jakub Kicinski <kubakici@wp.pl> > Cc: Tal Gilboa <talgi@mellanox.com>; Tariq Toukan <tariqt@mellanox.com>; > Keller, Jacob E <jacob.e.keller@intel.com>; Ariel Elior <ariel.elior@cavium.com>; > Ganesh Goudar <ganeshgr@chelsio.com>; Kirsher, Jeffrey T > <jeffrey.t.kirsher@intel.com>; everest-linux-l2@cavium.com; intel-wired- > lan@lists.osuosl.org; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; > linux-pci@vger.kernel.org > Subject: Re: [PATCH v5 05/14] PCI: Add pcie_print_link_status() to log link speed > and whether it's limited > > On Thu, Apr 12, 2018 at 09:32:49PM -0700, Jakub Kicinski wrote: > > On Fri, 30 Mar 2018 16:05:18 -0500, Bjorn Helgaas wrote: > > > + if (bw_avail >= bw_cap) > > > + pci_info(dev, "%d Mb/s available bandwidth (%s x%d link)\n", > > > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); > > > + else > > > + pci_info(dev, "%d Mb/s available bandwidth, limited by %s x%d > link at %s (capable of %d Mb/s with %s x%d link)\n", > > > + bw_avail, PCIE_SPEED2STR(speed), width, > > > + limiting_dev ? pci_name(limiting_dev) : "<unknown>", > > > + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); > > > > I was just looking at using this new function to print PCIe BW for a > > NIC, but I'm slightly worried that there is nothing in the message that > > says PCIe... For a NIC some people may interpret the bandwidth as NIC > > bandwidth: > > > > [ 39.839989] nfp 0000:04:00.0: Netronome Flow Processor NFP4000/NFP6000 > PCIe Card Probe > > [ 39.848943] nfp 0000:04:00.0: 63.008 Gb/s available bandwidth (8 GT/s x8 link) > > [ 39.857146] nfp 0000:04:00.0: RESERVED BARs: 0.0: General/MSI-X SRAM, 0.1: > PCIe XPB/MSI-X PBA, 0.4: Explicit0, 0.5: Explicit1, fre4 > > > > It's not a 63Gbps NIC... I'm sorry if this was discussed before and I > > didn't find it. Would it make sense to add the "PCIe: " prefix to the > > message like bnx2x used to do? Like: > > > > nfp 0000:04:00.0: PCIe: 63.008 Gb/s available bandwidth (8 GT/s x8 link) > > I agree, that does look potentially confusing. How about this: > > nfp 0000:04:00.0: 63.008 Gb/s available PCIe bandwidth (8 GT/s x8 link) > > I did have to look twice at this before I remembered that we're > printing Gb/s (not GB/s). Most of the references I found on the web > use GB/s when talking about total PCIe bandwidth. > > But either way I think it's definitely worth mentioning PCIe > explicitly. I also agree printing PCIe explicitly is good. Thanks, Jake
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c index e00d56b12747..cec7aed09f6b 100644 --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -5283,6 +5283,35 @@ u32 pcie_bandwidth_capable(struct pci_dev *dev, enum pci_bus_speed *speed, return *width * PCIE_SPEED2MBS_ENC(*speed); } +/** + * pcie_print_link_status - Report the PCI device's link speed and width + * @dev: PCI device to query + * + * Report the available bandwidth at the device. If this is less than the + * device is capable of, report the device's maximum possible bandwidth and + * the upstream link that limits its performance to less than that. + */ +void pcie_print_link_status(struct pci_dev *dev) +{ + enum pcie_link_width width, width_cap; + enum pci_bus_speed speed, speed_cap; + struct pci_dev *limiting_dev = NULL; + u32 bw_avail, bw_cap; + + bw_cap = pcie_bandwidth_capable(dev, &speed_cap, &width_cap); + bw_avail = pcie_bandwidth_available(dev, &limiting_dev, &speed, &width); + + if (bw_avail >= bw_cap) + pci_info(dev, "%d Mb/s available bandwidth (%s x%d link)\n", + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); + else + pci_info(dev, "%d Mb/s available bandwidth, limited by %s x%d link at %s (capable of %d Mb/s with %s x%d link)\n", + bw_avail, PCIE_SPEED2STR(speed), width, + limiting_dev ? pci_name(limiting_dev) : "<unknown>", + bw_cap, PCIE_SPEED2STR(speed_cap), width_cap); +} +EXPORT_SYMBOL(pcie_print_link_status); + /** * pci_select_bars - Make BAR mask from the type of resource * @dev: the PCI device for which BAR mask is made diff --git a/include/linux/pci.h b/include/linux/pci.h index f2bf2b7a66c7..38f7957121ef 100644 --- a/include/linux/pci.h +++ b/include/linux/pci.h @@ -1086,6 +1086,7 @@ int pcie_get_minimum_link(struct pci_dev *dev, enum pci_bus_speed *speed, u32 pcie_bandwidth_available(struct pci_dev *dev, struct pci_dev **limiting_dev, enum pci_bus_speed *speed, enum pcie_link_width *width); +void pcie_print_link_status(struct pci_dev *dev); void pcie_flr(struct pci_dev *dev); int __pci_reset_function_locked(struct pci_dev *dev); int pci_reset_function(struct pci_dev *dev);