kernel/tools/perf/tests/code-reading.c, branch linux-6.16.y

perf sample: Make user_regs and intr_regs optional

2025-02-13T04:06:11Z

The struct dump_regs contains 512 bytes of cache_regs, meaning the two values in perf_sample contribute 1088 bytes of its total 1384 bytes size. Initializing this much memory has a cost reported by Tavian Barnes as about 2.5% when running `perf script --itrace=i0`: https://lore.kernel.org/lkml/d841b97b3ad2ca8bcab07e4293375fb7c32dfce7.1736618095.git.tavianator@tavianator.com/ Adrian Hunter replied that the zero initialization was necessary and couldn't simply be removed. This patch aims to strike a middle ground of still zeroing the perf_sample, but removing 79% of its size by make user_regs and intr_regs optional pointers to zalloc-ed memory. To support the allocation accessors are created for user_regs and intr_regs. To support correct cleanup perf_sample__init and perf_sample__exit functions are created and added throughout the code base. Signed-off-by: Ian Rogers Link: https://lore.kernel.org/r/20250113194345.1537821-1-irogers@google.com Signed-off-by: Namhyung Kim

perf tests code-reading: Handle change in objdump output from binutils >= 2.41 on riscv

2025-01-08T20:20:42Z

After binutils commit e43d876 which was first included in binutils 2.41, riscv no longer supports dumping in the middle of instructions. Increase the objdump window by 2-bytes to ensure that any instruction that sits on the boundary of the specified stop-address is not cut in half. Signed-off-by: Charlie Jenkins Cc: Adrian Hunter Cc: Albert Ou Cc: Alexander Shishkin Cc: Bill Wendling Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Justin Stitt Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: linux-riscv@lists.infradead.org Link: https://lore.kernel.org/r/20241219-perf_fix_riscv_obj_reading-v3-1-a7d644dcfa50@rivosinc.com Signed-off-by: Arnaldo Carvalho de Melo

perf dso: Add reference count checking and accessor functions

2024-05-06T18:28:49Z

Add reference count checking to struct dso, this can help with implementing correct reference counting discipline. To avoid RC_CHK_ACCESS everywhere, add accessor functions for the variables in struct dso. The majority of the change is mechanical in nature and not easy to split up. Committer testing: 'perf test' up to this patch shows no regressions. But: util/symbol.c: In function ‘dso__load_bfd_symbols’: util/symbol.c:1683:9: error: too few arguments to function ‘dso__set_adjust_symbols’ 1683 | dso__set_adjust_symbols(dso); | ^~~~~~~~~~~~~~~~~~~~~~~ In file included from util/symbol.c:21: util/dso.h:268:20: note: declared here 268 | static inline void dso__set_adjust_symbols(struct dso *dso, bool val) | ^~~~~~~~~~~~~~~~~~~~~~~ make[6]: *** [/home/acme/git/perf-tools-next/tools/build/Makefile.build:106: /tmp/tmp.ZWHbQftdN6/util/symbol.o] Error 1 MKDIR /tmp/tmp.ZWHbQftdN6/tests/workloads/ make[6]: *** Waiting for unfinished jobs.... This was updated: - symbols__fixup_end(&dso->symbols, false); - symbols__fixup_duplicate(&dso->symbols); - dso->adjust_symbols = 1; + symbols__fixup_end(dso__symbols(dso), false); + symbols__fixup_duplicate(dso__symbols(dso)); + dso__set_adjust_symbols(dso); But not build tested with BUILD_NONDISTRO and libbfd devel files installed (binutils-devel on fedora). Add the missing argument: symbols__fixup_end(dso__symbols(dso), false); symbols__fixup_duplicate(dso__symbols(dso)); - dso__set_adjust_symbols(dso); + dso__set_adjust_symbols(dso, true); Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Ahelenia Ziemiańska Cc: Alexander Shishkin Cc: Andi Kleen Cc: Athira Rajeev Cc: Ben Gainey Cc: Changbin Du Cc: Chengen Du Cc: Colin Ian King Cc: Dima Kogan Cc: Ilkka Koskinen Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: K Prateek Nayak Cc: Kan Liang Cc: Leo Yan Cc: Li Dong Cc: Mark Rutland Cc: Masami Hiramatsu Cc: Namhyung Kim Cc: Paran Lee Cc: Peter Zijlstra Cc: Song Liu Cc: Sun Haiyong Cc: Thomas Richter Cc: Tiezhu Yang Cc: Yanteng Si Cc: zhaimingbing Link: https://lore.kernel.org/r/20240504213803.218974-6-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf tests: Apply attributes to all events in object code reading test

2024-04-12T15:02:05Z

PERF_PMU_CAP_EXTENDED_HW_TYPE results in multiple events being opened on heterogeneous systems. Currently this test only sets its required attributes on the first event. Not disabling enable_on_exec on the other events causes the test to fail because the forked objdump processes are sampled. No tracking event is opened so Perf only knows about its own mappings causing the objdump samples to give the following error: $ perf test -vvv "object code reading" Reading object code for memory address: 0xffff9aaa55ec thread__find_map failed ---- end(-1) ---- 24: Object code reading : FAILED! Fixes: 251aa040244a3b17 ("perf parse-events: Wildcard most "numeric" events") Reviewed-by: Ian Rogers Signed-off-by: James Clark Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Peter Zijlstra Cc: Spoorthy S Link: https://lore.kernel.org/r/20240410103458.813656-3-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo

libperf cpumap: Replace usage of perf_cpu_map__new(NULL) with perf_cpu_map__new_online_cpus()

2023-12-12T17:55:13Z

Passing NULL to perf_cpu_map__new() performs perf_cpu_map__new_online_cpus(), just directly call perf_cpu_map__new_online_cpus() to be more intention revealing. Reviewed-by: James Clark Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Alexandre Ghiti Cc: Andrew Jones Cc: André Almeida Cc: Athira Jajeev Cc: Atish Patra Cc: Changbin Du Cc: Darren Hart Cc: Davidlohr Bueso Cc: Huacai Chen Cc: Ingo Molnar Cc: Jiri Olsa Cc: John Garry Cc: K Prateek Nayak Cc: Kajol Jain Cc: Kan Liang Cc: Leo Yan Cc: Mark Rutland Cc: Mike Leach Cc: Namhyung Kim Cc: Nick Desaulniers Cc: Paolo Bonzini Cc: Paran Lee Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sandipan Das Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Suzuki Poulouse Cc: Thomas Gleixner Cc: Will Deacon Cc: Yang Jihong Cc: Yang Li Cc: Yanteng Si Cc: bpf@vger.kernel.org Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20231129060211.1890454-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf test: Add option to change objdump binary

2023-11-09T16:49:33Z

All of the other Perf subcommands that use objdump have an option to specify the binary, so add the same option to 'perf test'. This is useful if you have built the kernel with a different toolchain to the system one, where the system objdump may fail to disassemble vmlinux. Now this can be fixed with something like this: $ perf test --objdump llvm-objdump "object code reading" Reviewed-by: Ian Rogers Signed-off-by: James Clark Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Jajeev Cc: Fangrui Song Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kajol Jain Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Nathan Chancellor Cc: Nick Desaulniers Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Tom Rix Cc: Yang Jihong Cc: llvm@lists.linux.dev Link: https://lore.kernel.org/r/20231106151051.129440-2-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf test: Simplify "object code reading" test

2023-11-09T16:49:33Z

It tries cycles (or cpu-clock on s390) event with exclude_kernel bit to open. But other arch on a VM can fail with the hardware event and need to fallback to the software event in the same way. So let's get rid of the cpuid check and use generic fallback mechanism using an array of event candidates. Now event in the odd index excludes the kernel so use that for the return value. Reviewed-by: Adrian Hunter Signed-off-by: Namhyung Kim Tested-by: James Clark Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Peter Zijlstra Cc: Thomas Richter Link: https://lore.kernel.org/r/20231103195541.67788-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

tools/perf/tests: Fix object code reading to skip address that falls out of text section

2023-10-05T05:28:07Z

The testcase "Object code reading" fails in somecases for "fs_something" sub test as below: Reading object code for memory address: 0xc008000007f0142c File is: /lib/modules/6.5.0-rc3+/kernel/fs/xfs/xfs.ko On file address is: 0x1114cc Objdump command is: objdump -z -d --start-address=0x11142c --stop-address=0x1114ac /lib/modules/6.5.0-rc3+/kernel/fs/xfs/xfs.ko objdump read too few bytes: 128 test child finished with -1 This can alo be reproduced when running perf record with workload that exercises fs_something() code. In the test setup, this is exercising xfs code since root is xfs. # perf record ./a.out # perf report -v |grep "xfs.ko" 0.76% a.out /lib/modules/6.5.0-rc3+/kernel/fs/xfs/xfs.ko 0xc008000007de5efc B [k] xlog_cil_commit 0.74% a.out /lib/modules/6.5.0-rc3+/kernel/fs/xfs/xfs.ko 0xc008000007d5ae18 B [k] xfs_btree_key_offset 0.74% a.out /lib/modules/6.5.0-rc3+/kernel/fs/xfs/xfs.ko 0xc008000007e11fd4 B [k] 0x0000000000112074 Here addr "0xc008000007e11fd4" is not resolved. since this is a kernel module, its offset is from the DSO. Xfs module is loaded at 0xc008000007d00000 # cat /proc/modules | grep xfs xfs 2228224 3 - Live 0xc008000007d00000 And size is 0x220000. So its loaded between 0xc008000007d00000 and 0xc008000007f20000. From objdump, text section is: text 0010f7bc 0000000000000000 0000000000000000 000000a0 2**4 Hence perf captured ip maps to 0x112074 which is: ( ip - start of module ) + a0 This offset 0x112074 falls out .text section which is up to 0x10f7bc In this case for module, the address 0xc008000007e11fd4 is pointing to stub instructions. This address range represents the module stubs which is allocated on module load and hence is not part of DSO offset. To address this issue in "object code reading", skip the sample if address falls out of text section and is within the module end. Use the "text_end" member of "struct dso" to do this check. To address this issue in "perf report", exploring an option of having stubs range as part of the /proc/kallsyms, so that perf report can resolve addresses in stubs range However this patch uses text_end to skip the stub range for Object code reading testcase. Reported-by: Disha Goel Signed-off-by: Athira Rajeev Tested-by: Disha Goel Reviewed-by: Adrian Hunter Reviewed-by: Kajol Jain Cc: maddy@linux.ibm.com Cc: disgoel@linux.vnet.ibm.com Cc: linuxppc-dev@lists.ozlabs.org Link: https://lore.kernel.org/r/20230928075213.84392-3-atrajeev@linux.vnet.ibm.com Signed-off-by: Namhyung Kim

perf machine: Make delete_threads part of machine__exit

2023-06-12T18:57:53Z

The code required threads to be deleted before machine__exit was called or the threads would be leaked. This was error prone so move the delete_threads into machine__exit. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ali Saidi Cc: Andi Kleen Cc: Athira Rajeev Cc: Brian Robbins Cc: Changbin Du Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: Fangrui Song Cc: German Gomez Cc: Ingo Molnar Cc: Ivan Babrou Cc: James Clark Cc: Jing Zhang Cc: Jiri Olsa Cc: John Garry Cc: K Prateek Nayak Cc: Kan Liang Cc: Leo Yan Cc: Liam Howlett Cc: Mark Rutland Cc: Miguel Ojeda Cc: Mike Leach Cc: Namhyung Kim Cc: Naveen N. Rao Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Suzuki Poulouse Cc: Wenyu Liu Cc: Will Deacon Cc: Yang Jihong Cc: Ye Xingchen Cc: Yuan Can Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230608232823.4027869-9-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf addr_location: Add init/exit/copy functions

2023-06-12T18:57:53Z

struct addr_location holds references to multiple reference counted objects. Add init/exit functions to make maintenance of those more consistent with the rest of the code and to try to avoid leaks. Modification of thread reference counts isn't included in this change. Committer notes: I needed to initialize result to sample->ip to make sure is set to something, fixing a compile time error, mostly keeping the previous logic as build_alloc_func_list() already does debugging/error prints about what went wrong if it takes the 'goto out'. Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ali Saidi Cc: Andi Kleen Cc: Athira Rajeev Cc: Brian Robbins Cc: Changbin Du Cc: Dmitrii Dolgov <9erthalion6@gmail.com> Cc: Fangrui Song Cc: German Gomez Cc: Ingo Molnar Cc: Ivan Babrou Cc: James Clark Cc: Jing Zhang Cc: Jiri Olsa Cc: John Garry Cc: K Prateek Nayak Cc: Kan Liang Cc: Leo Yan Cc: Liam Howlett Cc: Mark Rutland Cc: Miguel Ojeda Cc: Mike Leach Cc: Namhyung Kim Cc: Naveen N. Rao Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Sean Christopherson Cc: Steinar H. Gunderson Cc: Suzuki Poulouse Cc: Wenyu Liu Cc: Will Deacon Cc: Yang Jihong Cc: Ye Xingchen Cc: Yuan Can Cc: coresight@lists.linaro.org Cc: linux-arm-kernel@lists.infradead.org Link: https://lore.kernel.org/r/20230608232823.4027869-7-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo