| Message ID | 20230324033342.3177979-1-suagrfillet@gmail.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | riscv: Optimize function trace | expand |
ping... Song Shuai <suagrfillet@gmail.com> 于2023年3月24日周五 11:33写道： > > The first 3 independent patches has been picked in the V7 version of > this series, this version continues the following 4 patches. > > select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1] (patch 1) > ========================================================== > > In RISC-V, -fpatchable-function-entry option is used to support > dynamic ftrace in this commit afc76b8b8011 ("riscv: Using > PATCHABLE_FUNCTION_ENTRY instead of MCOUNT"). So recordmcount > don't have to be called to create the __mcount_loc section before > the vmlinux linking. > > Here selects FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to tell > Makefile not to run recordmcount. > > Make function graph use ftrace directly [2] (patch 2) > ======================================================== > > In RISC-V architecture, when we enable the ftrace_graph tracer on some > functions, the function tracings on other functions will suffer extra > graph tracing work. In essence, graph_ops isn't limited by its func_hash > due to the global ftrace_graph_[regs]_call label. That should be > corrected. > > What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function > graph use ftrace directly") that uses graph_ops::func function to > install return_hooker and makes the function called against its > func_hash. > > This series of patches makes function graph use ftrace directly for > riscv. > > If FTRACE_WITH_REGS isn't defined, ftrace_caller keeps ftrace_graph_call > so that it can be replaced with the calling of prepare_ftrace_return by > the enable/disable helper. > > As for defining FTRACE_WITH_REGS, ftrace_caller is adjusted to save the > necessary regs against the pt_regs layout, so it can reasonably call the > graph_ops::func function - ftrace_graph_func. And > ftrace_graph_[regs]_call > and its enable/disable helper aren't needed. > > Test log: > > The tests generated by CONFIG_FTRACE_STARTUP_TEST have passed in the > local > qemu-system-riscv64 virt machine. The following is the log during > startup. > > ``` > Nov 15 03:07:13 stage4 kernel: Testing tracer function: PASSED > Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace: PASSED > Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #1: > Nov 15 03:07:13 stage4 kernel: (1 0 1 0 0) > Nov 15 03:07:13 stage4 kernel: (1 1 2 0 0) > Nov 15 03:07:13 stage4 kernel: (2 1 3 0 365) > Nov 15 03:07:13 stage4 kernel: (2 2 4 0 399) > Nov 15 03:07:13 stage4 kernel: (3 2 4 0 146071) > Nov 15 03:07:13 stage4 kernel: (3 3 5 0 146105) PASSED > Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #2: > Nov 15 03:07:13 stage4 kernel: (1 0 1 589 0) > Nov 15 03:07:13 stage4 kernel: (1 1 2 635 0) > Nov 15 03:07:13 stage4 kernel: (2 1 3 1 2) > Nov 15 03:07:13 stage4 kernel: (2 2 4 125 126) > Nov 15 03:07:13 stage4 kernel: (3 2 4 146001 146078) > Nov 15 03:07:13 stage4 kernel: (3 3 5 146035 146112) PASSED > Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion: PASSED > Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion safe: PASSED > Nov 15 03:07:13 stage4 kernel: Testing ftrace regs: PASSED > Nov 15 03:07:13 stage4 kernel: Testing tracer nop: PASSED > Nov 15 03:07:13 stage4 kernel: Testing tracer irqsoff: PASSED > Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup: > Nov 15 03:07:13 stage4 kernel: sched: DL replenish lagged too much > Nov 15 03:07:13 stage4 kernel: PASSED > Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_rt: PASSED > Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_dl: PASSED > Nov 15 03:07:13 stage4 kernel: Testing tracer function_graph: PASSED > ``` > > Add WITH_DIRECT_CALLS support [3] (patch 3, 4) > ============================================== > > This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V. > SAMPLE_FTRACE_DIRECT and SAMPLE_FTRACE_DIRECT_MULTI are also included > here as the samples for testing DIRECT_CALLS related interface. > > First, select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide > register_ftrace_direct[_multi] interfaces allowing user to register > the customed trampoline (direct_caller) as the mcount for one or > more target functions. And modify_ftrace_direct[_multi] are also > provided for modify direct_caller. > > At the same time, the samples in ./samples/ftrace/ can be built > as kerenl module for testing these interfaces with SAMPLE_FTRACE_DIRECT > and SAMPLE_FTRACE_DIRECT_MULTI selected. > > Second, to make the direct_caller and the other ftrace hooks > (eg. function/fgraph tracer, k[ret]probes) co-exist, a temporary register > are nominated to store the address of direct_caller in ftrace_regs_caller. > After the setting of the address direct_caller by direct_ops->func and > the RESTORE_REGS in ftrace_regs_caller, direct_caller will be jumped to > by the `jr` inst. > > The following tests have been passed in my local qemu-riscv64 virt > machine. > > 1. tests with CONFIG_FTRACE_STARTUP_TEST > 2. tests of samples/ftrace/ftrace*.ko > 3. manual tests with any combination of the following hooks > - function/function_graph tracer > - ftrace*.ko > - kprobe/kretprobe > > For your reference, here is the log when function tracer, kretprobe and > ftrace-direct-too.ko co-hooks the handle_mm_fault function. > > ``` > [root@stage4 tracing]# echo handle_mm_fault > set_ftrace_filter > [root@stage4 tracing]# echo 'r:myr handle_mm_fault' > kprobe_events > [root@stage4 tracing]# echo function > current_tracer > [root@stage4 tracing]# echo 1 > events/kprobes/myr/enable > [root@stage4 tracing]# insmod /root/ftrace-direct-too.ko > [root@stage4 tracing]# > [root@stage4 tracing]# cat trace | tail > cat-388 [000] ...1. 583.051438: myr: > (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) > cat-388 [000] ...2. 583.057930: handle_mm_fault > <-do_page_fault > cat-388 [000] ..... 583.057990: my_direct_func: > handle mm fault vma=000000002d9fe19c address=ffffffae9b7000 flags=215 > cat-388 [000] ...1. 583.058284: myr: > (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) > tail-389 [001] ...2. 583.059062: handle_mm_fault > <-do_page_fault > tail-389 [001] ..... 583.059104: my_direct_func: > handle mm fault vma=0000000017f3c48e address=aaaaaabebf3000 flags=215 > tail-389 [001] ...1. 583.059325: myr: > (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) > tail-389 [001] ...2. 583.060371: handle_mm_fault > <-do_page_fault > tail-389 [001] ..... 583.060410: my_direct_func: > handle mm fault vma=0000000017f3c48e address=aaaaaabebf1000 flags=255 > tail-389 [001] ...1. 583.060996: myr: > (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) > ``` > Note1: > > The checkpatch.pl will output some warnings on this series, like this > > ``` > WARNING: Prefer using '"%s...", __func__' to using 'my_direct_func2', > this function's name, in a string > 111: FILE: samples/ftrace/ftrace-direct-multi-modify.c:48: > +" call my_direct_func2\n" > ``` > The reason is that checkpatch depends on patch context providing the > function name. In the above warning, my_direct_func2 has some codeline > distance with the changed trunk, so its declaration doesn't come into > the patch, and then the warning jumps out. > > You may notice the location of `my_ip` variable changes in the 2nd > patch. I did that for reducing the warnings to some extent. But killing > all the warnings will makes the patch less readable, so I stopped here. > > [1] > https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t > [2] > https://lore.kernel.org/lkml/20221120084230.910152-1-suagrfillet@gmail.com/ > [3] > https://lore.kernel.org/linux-riscv/20221123142025.1504030-1-suagrfillet@gmail.com/ > > The series's changes related these patches > ========================================== > > Changes in v8: > - Fix incorrect address values in the 4nd patch > - Rebased on v6.3-rc2 > > Changes in v7: > https://lore.kernel.org/linux-riscv/20230112090603.1295340-1-guoren@kernel.org/ > - Fixup RESTORE_ABI_REGS by remove PT_T0(sp) overwrite. > - Add FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY > - Fixup kconfig with HAVE_SAMPLE_FTRACE_DIRECT & > HAVE_SAMPLE_FTRACE_DIRECT_MULTI > > Changes in v6: > https://lore.kernel.org/linux-riscv/20230107133549.4192639-1-guoren@kernel.org/ > - Replace 8 with MCOUNT_INSN_SIZE > - Replace "REG_L a1, PT_RA(sp)" with "mv a1, ra" > - Add Evgenii Shatokhin comment > > Changes in v5: > https://lore.kernel.org/linux-riscv/20221208091244.203407-1-guoren@kernel.org/ > - Sort Kconfig entries in alphabetical order. > > Changes in v4: > https://lore.kernel.org/linux-riscv/20221129033230.255947-1-guoren@kernel.org/ > - Include [3] for maintenance. [Song Shuai] > > Changes in V3: > https://lore.kernel.org/linux-riscv/20221123153950.2911981-1-guoren@kernel.org/ > - Include [2] for maintenance. [Song Shuai] > > Song Shuai (4): > riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY > riscv: ftrace: Add ftrace_graph_func > riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support > samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI] > > arch/riscv/Kconfig | 4 + > arch/riscv/include/asm/ftrace.h | 19 ++- > arch/riscv/kernel/ftrace.c | 30 ++-- > arch/riscv/kernel/mcount-dyn.S | 143 +++++++++++++++----- > samples/ftrace/ftrace-direct-modify.c | 33 +++++ > samples/ftrace/ftrace-direct-multi-modify.c | 39 ++++++ > samples/ftrace/ftrace-direct-multi.c | 23 ++++ > samples/ftrace/ftrace-direct-too.c | 26 ++++ > samples/ftrace/ftrace-direct.c | 22 +++ > 9 files changed, 284 insertions(+), 55 deletions(-) > > -- > 2.20.1 >
The first 3 independent patches has been picked in the V7 version of this series, this version continues the following 4 patches. select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY [1] (patch 1) ========================================================== In RISC-V, -fpatchable-function-entry option is used to support dynamic ftrace in this commit afc76b8b8011 ("riscv: Using PATCHABLE_FUNCTION_ENTRY instead of MCOUNT"). So recordmcount don't have to be called to create the __mcount_loc section before the vmlinux linking. Here selects FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY to tell Makefile not to run recordmcount. Make function graph use ftrace directly [2] (patch 2) ======================================================== In RISC-V architecture, when we enable the ftrace_graph tracer on some functions, the function tracings on other functions will suffer extra graph tracing work. In essence, graph_ops isn't limited by its func_hash due to the global ftrace_graph_[regs]_call label. That should be corrected. What inspires me is the commit 0c0593b45c9b ("x86/ftrace: Make function graph use ftrace directly") that uses graph_ops::func function to install return_hooker and makes the function called against its func_hash. This series of patches makes function graph use ftrace directly for riscv. If FTRACE_WITH_REGS isn't defined, ftrace_caller keeps ftrace_graph_call so that it can be replaced with the calling of prepare_ftrace_return by the enable/disable helper. As for defining FTRACE_WITH_REGS, ftrace_caller is adjusted to save the necessary regs against the pt_regs layout, so it can reasonably call the graph_ops::func function - ftrace_graph_func. And ftrace_graph_[regs]_call and its enable/disable helper aren't needed. Test log: The tests generated by CONFIG_FTRACE_STARTUP_TEST have passed in the local qemu-system-riscv64 virt machine. The following is the log during startup. ``` Nov 15 03:07:13 stage4 kernel: Testing tracer function: PASSED Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace: PASSED Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #1: Nov 15 03:07:13 stage4 kernel: (1 0 1 0 0) Nov 15 03:07:13 stage4 kernel: (1 1 2 0 0) Nov 15 03:07:13 stage4 kernel: (2 1 3 0 365) Nov 15 03:07:13 stage4 kernel: (2 2 4 0 399) Nov 15 03:07:13 stage4 kernel: (3 2 4 0 146071) Nov 15 03:07:13 stage4 kernel: (3 3 5 0 146105) PASSED Nov 15 03:07:13 stage4 kernel: Testing dynamic ftrace ops #2: Nov 15 03:07:13 stage4 kernel: (1 0 1 589 0) Nov 15 03:07:13 stage4 kernel: (1 1 2 635 0) Nov 15 03:07:13 stage4 kernel: (2 1 3 1 2) Nov 15 03:07:13 stage4 kernel: (2 2 4 125 126) Nov 15 03:07:13 stage4 kernel: (3 2 4 146001 146078) Nov 15 03:07:13 stage4 kernel: (3 3 5 146035 146112) PASSED Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion: PASSED Nov 15 03:07:13 stage4 kernel: Testing ftrace recursion safe: PASSED Nov 15 03:07:13 stage4 kernel: Testing ftrace regs: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer nop: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer irqsoff: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup: Nov 15 03:07:13 stage4 kernel: sched: DL replenish lagged too much Nov 15 03:07:13 stage4 kernel: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_rt: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer wakeup_dl: PASSED Nov 15 03:07:13 stage4 kernel: Testing tracer function_graph: PASSED ``` Add WITH_DIRECT_CALLS support [3] (patch 3, 4) ============================================== This series adds DYNAMIC_FTRACE_WITH_DIRECT_CALLS support for RISC-V. SAMPLE_FTRACE_DIRECT and SAMPLE_FTRACE_DIRECT_MULTI are also included here as the samples for testing DIRECT_CALLS related interface. First, select the DYNAMIC_FTRACE_WITH_DIRECT_CALLS to provide register_ftrace_direct[_multi] interfaces allowing user to register the customed trampoline (direct_caller) as the mcount for one or more target functions. And modify_ftrace_direct[_multi] are also provided for modify direct_caller. At the same time, the samples in ./samples/ftrace/ can be built as kerenl module for testing these interfaces with SAMPLE_FTRACE_DIRECT and SAMPLE_FTRACE_DIRECT_MULTI selected. Second, to make the direct_caller and the other ftrace hooks (eg. function/fgraph tracer, k[ret]probes) co-exist, a temporary register are nominated to store the address of direct_caller in ftrace_regs_caller. After the setting of the address direct_caller by direct_ops->func and the RESTORE_REGS in ftrace_regs_caller, direct_caller will be jumped to by the `jr` inst. The following tests have been passed in my local qemu-riscv64 virt machine. 1. tests with CONFIG_FTRACE_STARTUP_TEST 2. tests of samples/ftrace/ftrace*.ko 3. manual tests with any combination of the following hooks - function/function_graph tracer - ftrace*.ko - kprobe/kretprobe For your reference, here is the log when function tracer, kretprobe and ftrace-direct-too.ko co-hooks the handle_mm_fault function. ``` [root@stage4 tracing]# echo handle_mm_fault > set_ftrace_filter [root@stage4 tracing]# echo 'r:myr handle_mm_fault' > kprobe_events [root@stage4 tracing]# echo function > current_tracer [root@stage4 tracing]# echo 1 > events/kprobes/myr/enable [root@stage4 tracing]# insmod /root/ftrace-direct-too.ko [root@stage4 tracing]# [root@stage4 tracing]# cat trace | tail cat-388 [000] ...1. 583.051438: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) cat-388 [000] ...2. 583.057930: handle_mm_fault <-do_page_fault cat-388 [000] ..... 583.057990: my_direct_func: handle mm fault vma=000000002d9fe19c address=ffffffae9b7000 flags=215 cat-388 [000] ...1. 583.058284: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) tail-389 [001] ...2. 583.059062: handle_mm_fault <-do_page_fault tail-389 [001] ..... 583.059104: my_direct_func: handle mm fault vma=0000000017f3c48e address=aaaaaabebf3000 flags=215 tail-389 [001] ...1. 583.059325: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) tail-389 [001] ...2. 583.060371: handle_mm_fault <-do_page_fault tail-389 [001] ..... 583.060410: my_direct_func: handle mm fault vma=0000000017f3c48e address=aaaaaabebf1000 flags=255 tail-389 [001] ...1. 583.060996: myr: (do_page_fault+0x16c/0x5f2 <- handle_mm_fault) ``` Note1: The checkpatch.pl will output some warnings on this series, like this ``` WARNING: Prefer using '"%s...", __func__' to using 'my_direct_func2', this function's name, in a string 111: FILE: samples/ftrace/ftrace-direct-multi-modify.c:48: +" call my_direct_func2\n" ``` The reason is that checkpatch depends on patch context providing the function name. In the above warning, my_direct_func2 has some codeline distance with the changed trunk, so its declaration doesn't come into the patch, and then the warning jumps out. You may notice the location of `my_ip` variable changes in the 2nd patch. I did that for reducing the warnings to some extent. But killing all the warnings will makes the patch less readable, so I stopped here. [1] https://lore.kernel.org/linux-riscv/CAAYs2=j3Eak9vU6xbAw0zPuoh00rh8v5C2U3fePkokZFibWs2g@mail.gmail.com/T/#t [2] https://lore.kernel.org/lkml/20221120084230.910152-1-suagrfillet@gmail.com/ [3] https://lore.kernel.org/linux-riscv/20221123142025.1504030-1-suagrfillet@gmail.com/ The series's changes related these patches ========================================== Changes in v8: - Fix incorrect address values in the 4nd patch - Rebased on v6.3-rc2 Changes in v7: https://lore.kernel.org/linux-riscv/20230112090603.1295340-1-guoren@kernel.org/ - Fixup RESTORE_ABI_REGS by remove PT_T0(sp) overwrite. - Add FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY - Fixup kconfig with HAVE_SAMPLE_FTRACE_DIRECT & HAVE_SAMPLE_FTRACE_DIRECT_MULTI Changes in v6: https://lore.kernel.org/linux-riscv/20230107133549.4192639-1-guoren@kernel.org/ - Replace 8 with MCOUNT_INSN_SIZE - Replace "REG_L a1, PT_RA(sp)" with "mv a1, ra" - Add Evgenii Shatokhin comment Changes in v5: https://lore.kernel.org/linux-riscv/20221208091244.203407-1-guoren@kernel.org/ - Sort Kconfig entries in alphabetical order. Changes in v4: https://lore.kernel.org/linux-riscv/20221129033230.255947-1-guoren@kernel.org/ - Include [3] for maintenance. [Song Shuai] Changes in V3: https://lore.kernel.org/linux-riscv/20221123153950.2911981-1-guoren@kernel.org/ - Include [2] for maintenance. [Song Shuai] Song Shuai (4): riscv: select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY riscv: ftrace: Add ftrace_graph_func riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI] arch/riscv/Kconfig | 4 + arch/riscv/include/asm/ftrace.h | 19 ++- arch/riscv/kernel/ftrace.c | 30 ++-- arch/riscv/kernel/mcount-dyn.S | 143 +++++++++++++++----- samples/ftrace/ftrace-direct-modify.c | 33 +++++ samples/ftrace/ftrace-direct-multi-modify.c | 39 ++++++ samples/ftrace/ftrace-direct-multi.c | 23 ++++ samples/ftrace/ftrace-direct-too.c | 26 ++++ samples/ftrace/ftrace-direct.c | 22 +++ 9 files changed, 284 insertions(+), 55 deletions(-)