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2025-04-29perf tools: Fix in-source libperf buildJames Clark
When libperf is built alone in-source, $(OUTPUT) isn't set. This causes the generated uapi path to resolve to '/../arch' which results in a permissions error: mkdir: cannot create directory '/../arch': Permission denied Fix it by removing the preceding '/..' which means that it gets generated either in the tools/lib/perf part of the tree or the OUTPUT folder. Some other rules that rely on OUTPUT further refine this conditionally depending on whether it's an in-source or out-of-source build, but I don't think we need the extra complexity here. And this rule is slightly different to others because the header is needed by both libperf and Perf. This is further complicated by the fact that Perf always passes O=... to libperf even for in source builds, meaning that OUTPUT isn't set consistently between projects. Because we're no longer going one level up to try to generate the file in the tools/ folder, Perf's include rule needs to descend into libperf. Also fix the clean rule while we're here. Reported-by: Thorsten Leemhuis <linux@leemhuis.info> Closes: https://lore.kernel.org/linux-perf-users/7703f88e-ccb7-4c98-9da4-8aad224e780f@leemhuis.info/ Fixes: bfb713ea53c7 ("perf tools: Fix arm64 build by generating unistd_64.h") Signed-off-by: James Clark <james.clark@linaro.org> Tested-by: Thorsten Leemhuis <linux@leemhuis.info> Link: https://lore.kernel.org/r/20250429-james-perf-fix-libperf-in-source-build-v1-1-a1a827ac15e5@linaro.org Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2025-04-23perf tools: Fix arm64 build by generating unistd_64.hJames Clark
Since pulling in the kernel changes in commit 22f72088ffe6 ("tools headers: Update the syscall table with the kernel sources"), arm64 is no longer using a generic syscall header and generates one from the syscall table. Therefore we must also generate the syscall header for arm64 before building Perf. Add it as a dependency to libperf which uses one syscall number. Perf uses more, but as libperf is a dependency of Perf it will be generated for both. Future platforms that need this will have to add their own syscall-y targets in libperf manually. Unfortunately the arch specific files that do this (e.g. arch/arm64/include/asm/Kbuild) can't easily be imported into the Perf build. But Perf only needs a subset of the generated files anyway, so redefining them is probably the correct thing to do. Fixes: 22f72088ffe6 ("tools headers: Update the syscall table with the kernel sources") Signed-off-by: James Clark <james.clark@linaro.org> Tested-by: Harshit Mogalapalli <harshit.m.mogalapalli@oracle.com> Link: https://lore.kernel.org/r/20250417-james-perf-fix-gen-syscall-v1-1-1d268c923901@linaro.org Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2025-03-31Merge tag 'perf-tools-for-v6.15-2025-03-27' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools Pull perf tools updates from Namhyung Kim: "perf record: - Introduce latency profiling using scheduler information. The latency profiling is to show impacts on wall-time rather than cpu-time. By tracking context switches, it can weight samples and find which part of the code contributed more to the execution latency. The value (period) of the sample is weighted by dividing it by the number of parallel execution at the moment. The parallelism is tracked in perf report with sched-switch records. This will reduce the portion that are run in parallel and in turn increase the portion of serial executions. For now, it's limited to profile processes, IOW system-wide profiling is not supported. You can add --latency option to enable this. $ perf record --latency -- make -C tools/perf I've run the above command for perf build which adds -j option to make with the number of CPUs in the system internally. Normally it'd show something like below: $ perf report -F overhead,comm ... # # Overhead Command # ........ ............... # 78.97% cc1 6.54% python3 4.21% shellcheck 3.28% ld 1.80% as 1.37% cc1plus 0.80% sh 0.62% clang 0.56% gcc 0.44% perl 0.39% make ... The cc1 takes around 80% of the overhead as it's the actual compiler. However it runs in parallel so its contribution to latency may be less than that. Now, perf report will show both overhead and latency (if --latency was given at record time) like below: $ perf report -s comm ... # # Overhead Latency Command # ........ ........ ............... # 78.97% 48.66% cc1 6.54% 25.68% python3 4.21% 0.39% shellcheck 3.28% 13.70% ld 1.80% 2.56% as 1.37% 3.08% cc1plus 0.80% 0.98% sh 0.62% 0.61% clang 0.56% 0.33% gcc 0.44% 1.71% perl 0.39% 0.83% make ... You can see latency of cc1 goes down to around 50% and python3 and ld contribute a lot more than their overhead. You can use --latency option in perf report to get the same result but ordered by latency. $ perf report --latency -s comm perf report: - As a side effect of the latency profiling work, it adds a new output field 'latency' and a sort key 'parallelism'. The below is a result from my system with 64 CPUs. The build was well-parallelized but contained some serial portions. $ perf report -s parallelism ... # # Overhead Latency Parallelism # ........ ........ ........... # 16.95% 1.54% 62 13.38% 1.24% 61 12.50% 70.47% 1 11.81% 1.06% 63 7.59% 0.71% 60 4.33% 12.20% 2 3.41% 0.33% 59 2.05% 0.18% 64 1.75% 1.09% 9 1.64% 1.85% 5 ... - Support Feodra mini-debuginfo which is a LZMA compressed symbol table inside ".gnu_debugdata" ELF section. perf annotate: - Add --code-with-type option to enable data-type profiling with the usual annotate output. Instead of focusing on data structure, it shows code annotation together with data type it accesses in case the instruction refers to a memory location (and it was able to resolve the target data type). Currently it only works with --stdio. $ perf annotate --stdio --code-with-type ... Percent | Source code & Disassembly of vmlinux for cpu/mem-loads,ldlat=30/pp (18 samples, percent: local period) ---------------------------------------------------------------------------------------------------------------------- : 0 0xffffffff81050610 <__fdget>: 0.00 : ffffffff81050610: callq 0xffffffff81c01b80 <__fentry__> # data-type: (stack operation) 0.00 : ffffffff81050615: pushq %rbp # data-type: (stack operation) 0.00 : ffffffff81050616: movq %rsp, %rbp 0.00 : ffffffff81050619: pushq %r15 # data-type: (stack operation) 0.00 : ffffffff8105061b: pushq %r14 # data-type: (stack operation) 0.00 : ffffffff8105061d: pushq %rbx # data-type: (stack operation) 0.00 : ffffffff8105061e: subq $0x10, %rsp 0.00 : ffffffff81050622: movl %edi, %ebx 0.00 : ffffffff81050624: movq %gs:0x7efc4814(%rip), %rax # 0x14e40 <current_task> # data-type: struct task_struct* +0 0.00 : ffffffff8105062c: movq 0x8d0(%rax), %r14 # data-type: struct task_struct +0x8d0 (files) 0.00 : ffffffff81050633: movl (%r14), %eax # data-type: struct files_struct +0 (count.counter) 0.00 : ffffffff81050636: cmpl $0x1, %eax 0.00 : ffffffff81050639: je 0xffffffff810506a9 <__fdget+0x99> 0.00 : ffffffff8105063b: movq 0x20(%r14), %rcx # data-type: struct files_struct +0x20 (fdt) 0.00 : ffffffff8105063f: movl (%rcx), %eax # data-type: struct fdtable +0 (max_fds) 0.00 : ffffffff81050641: cmpl %ebx, %eax 0.00 : ffffffff81050643: jbe 0xffffffff810506ef <__fdget+0xdf> 0.00 : ffffffff81050649: movl %ebx, %r15d 5.56 : ffffffff8105064c: movq 0x8(%rcx), %rdx # data-type: struct fdtable +0x8 (fd) ... The "# data-type:" part was added with this change. The first few entries are not very interesting. But later you can it accesses a couple of fields in the task_struct, files_struct and fdtable. perf trace: - Support syscall tracing for different ABI. For example it can trace system calls for 32-bit applications on 64-bit kernel transparently. - Add --summary-mode=total option to show global syscall summary. The default is 'thread' to show per-thread syscall summary. Python support: - Add more interfaces to 'perf' module to parse events, and config, enable or disable the event list properly so that it can implement basic functionalities purely in Python. There is an example code for these new interfaces in python/tracepoint.py. - Add mypy and pylint support to enable build time checking. Fix some code based on the findings from these tools. Internals: - Introduce io_dir__readdir() API to make directory traveral (usually for proc or sysfs) efficient with less memory footprint. JSON vendor events: - Add events and metrics for ARM Neoverse N3 and V3 - Update events and metrics on various Intel CPUs - Add/update events for a number of SiFive processors" * tag 'perf-tools-for-v6.15-2025-03-27' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (229 commits) perf bpf-filter: Fix a parsing error with comma perf report: Fix a memory leak for perf_env on AMD perf trace: Fix wrong size to bpf_map__update_elem call perf tools: annotate asm_pure_loop.S perf python: Fix setup.py mypy errors perf test: Address attr.py mypy error perf build: Add pylint build tests perf build: Add mypy build tests perf build: Rename TEST_LOGS to SHELL_TEST_LOGS tools/build: Don't pass test log files to linker perf bench sched pipe: fix enforced blocking reads in worker_thread perf tools: Fix is_compat_mode build break in ppc64 perf build: filter all combinations of -flto for libperl perf vendor events arm64 AmpereOneX: Fix frontend_bound calculation perf vendor events arm64: AmpereOne/AmpereOneX: Mark LD_RETIRED impacted by errata perf trace: Fix evlist memory leak perf trace: Fix BTF memory leak perf trace: Make syscall table stable perf syscalltbl: Mask off ABI type for MIPS system calls perf build: Remove Makefile.syscalls ...
2025-03-19libperf: Don't remove -g when EXTRA_CFLAGS are usedJames Clark
When using EXTRA_CFLAGS, for example "EXTRA_CFLAGS=-DREFCNT_CHECKING=1", this construct stops setting -g which you'd expect would not be affected by adding extra flags. Additionally, EXTRA_CFLAGS should be the last thing to be appended so that it can be used to undo any defaults. And no condition is required, just += appends to any existing CFLAGS and also appends or doesn't append EXTRA_CFLAGS if they are or aren't set. It's not clear why DEBUG=1 is required for -g in Perf when in libperf it's always on, but I don't think we need to change that behavior now because someone may be depending on it. Signed-off-by: James Clark <james.clark@linaro.org> Reviewed-by: Ian Rogers <irogers@google.com> Link: https://lore.kernel.org/r/20250319114009.417865-1-james.clark@linaro.org Signed-off-by: Namhyung Kim <namhyung@kernel.org>
2025-02-18tools: Remove redundant quiet setupCharlie Jenkins
Q is exported from Makefile.include so it is not necessary to manually set it. Reviewed-by: Jiri Olsa <jolsa@kernel.org> Signed-off-by: Charlie Jenkins <charlie@rivosinc.com> Acked-by: Andrii Nakryiko <andrii@kernel.org> Acked-by: Quentin Monnet <qmo@kernel.org> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Benjamin Tissoires <bentiss@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Daniel Lezcano <daniel.lezcano@linaro.org> Cc: Eduard Zingerman <eddyz87@gmail.com> Cc: Hao Luo <haoluo@google.com> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Kosina <jikos@kernel.org> Cc: John Fastabend <john.fastabend@gmail.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: KP Singh <kpsingh@kernel.org> Cc: Lukasz Luba <lukasz.luba@arm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Mykola Lysenko <mykolal@fb.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Rafael J. Wysocki <rafael@kernel.org> Cc: Shuah Khan <shuah@kernel.org> Cc: Song Liu <song@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Yonghong Song <yonghong.song@linux.dev> Cc: Zhang Rui <rui.zhang@intel.com> Link: https://lore.kernel.org/r/20250213-quiet_tools-v3-2-07de4482a581@rivosinc.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2023-04-17perf cpumap: Add reference count checkingIan Rogers
Enabled when REFCNT_CHECKING is defined. The change adds a memory allocated pointer that is interposed between the reference counted cpu map at a get and freed by a put. The pointer replaces the original perf_cpu_map struct, so use of the perf_cpu_map via APIs remains unchanged. Any use of the cpu map without the API requires two versions, handled via the RC_CHK_ACCESS macro. This change is intended to catch: - use after put: using a cpumap after you have put it will cause a segv. - unbalanced puts: two puts for a get will result in a double free that can be captured and reported by tools like address sanitizer, including with the associated stack traces of allocation and frees. - missing puts: if a put is missing then the get turns into a memory leak that can be reported by leak sanitizer, including the stack trace at the point the get occurs. Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexey Bayduraev <alexey.v.bayduraev@linux.intel.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: Darren Hart <dvhart@infradead.org> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Dmitriy Vyukov <dvyukov@google.com> Cc: Eric Dumazet <edumazet@google.com> Cc: German Gomez <german.gomez@arm.com> Cc: Hao Luo <haoluo@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: James Clark <james.clark@arm.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Garry <john.g.garry@oracle.com> Cc: Kajol Jain <kjain@linux.ibm.com> Cc: Kan Liang <kan.liang@linux.intel.com> Cc: Leo Yan <leo.yan@linaro.org> Cc: Madhavan Srinivasan <maddy@linux.ibm.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Miaoqian Lin <linmq006@gmail.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Riccardo Mancini <rickyman7@gmail.com> Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com> Cc: Song Liu <song@kernel.org> Cc: Stephen Brennan <stephen.s.brennan@oracle.com> Cc: Steven Rostedt (VMware) <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Thomas Richter <tmricht@linux.ibm.com>, Cc: Yury Norov <yury.norov@gmail.com> Link: https://lore.kernel.org/lkml/20230407230405.2931830-3-irogers@google.com [ Extracted from a larger patch ] Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-12-16libperf: Fix install_pkgconfig targetAlexander Gordeev
Commit 47e02b94a4c98dcc ("tools lib perf: Add dependency test to install_headers") misses the notion of $(DESTDIR_SQ) for install_pkgconfig target, which leads to error: install: cannot create regular file '/usr/lib64/pkgconfig/libperf.pc': Permission denied make: *** [Makefile:210: install_pkgconfig] Error 1 Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Rix <trix@redhat.com> Cc: bpf@vger.kernel.org Cc: llvm@lists.linux.dev Link: http://lore.kernel.org/lkml/Y5w/cWKyb8vpNMfA@li-4a3a4a4c-28e5-11b2-a85c-a8d192c6f089.ibm.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-12-14tools lib perf: Add dependency test to install_headersIan Rogers
Compute the headers to be installed from their source headers and make each have its own build target to install it. Using dependencies avoids headers being reinstalled and getting a new timestamp which then causes files that depend on the header to be rebuilt. Signed-off-by: Ian Rogers <irogers@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: Tom Rix <trix@redhat.com> Cc: bpf@vger.kernel.org Cc: llvm@lists.linux.dev Link: https://lore.kernel.org/r/20221202045743.2639466-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-11-20tools lib perf: Make install_headers clearerIan Rogers
Add libperf to the name so that this install_headers build appears different to similar targets in different libraries. Signed-off-by: Ian Rogers <irogers@google.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Alexei Starovoitov <ast@kernel.org> Cc: Andrii Nakryiko <andrii@kernel.org> Cc: Daniel Borkmann <daniel@iogearbox.net> Cc: Hao Luo <haoluo@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: John Fastabend <john.fastabend@gmail.com> Cc: KP Singh <kpsingh@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Martin KaFai Lau <martin.lau@linux.dev> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Song Liu <song@kernel.org> Cc: Stanislav Fomichev <sdf@google.com> Cc: Stephane Eranian <eranian@google.com> Cc: Yonghong Song <yhs@fb.com> Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20221117004356.279422-5-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-11-16tools lib perf: Add missing install headersIan Rogers
Headers necessary for the perf build. Note, internal headers are also installed as these are necessary for the build. Signed-off-by: Ian Rogers <irogers@google.com> Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Nicolas Schier <nicolas@fjasle.eu> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Cc: bpf@vger.kernel.org Link: http://lore.kernel.org/lkml/20221109184914.1357295-9-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2022-02-15kbuild: replace $(if A,A,B) with $(or A,B)Masahiro Yamada
$(or ...) is available since GNU Make 3.81, and useful to shorten the code in some places. Covert as follows: $(if A,A,B) --> $(or A,B) This patch also converts: $(if A, A, B) --> $(or A, B) Strictly speaking, the latter is not an equivalent conversion because GNU Make keeps spaces after commas; if A is not empty, $(if A, A, B) expands to " A", while $(or A, B) expands to "A". Anyway, preceding spaces are not significant in the code hunks I touched. Signed-off-by: Masahiro Yamada <masahiroy@kernel.org> Reviewed-by: Nicolas Schier <nicolas@fjasle.eu>
2021-07-07libperf: Change tests to single static and shared binariesJiri Olsa
Make tests to be two binaries 'tests_static' and 'tests_shared', so the maintenance is easier. Adding tests under libperf build system, so we define all the flags just once. Adding make-tests tule to just compile tests without running them. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Shunsuke Nakamura <nakamura.shun@fujitsu.com> Link: http://lore.kernel.org/lkml/20210706151704.73662-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-01-06libperf: Add man pagesJiri Olsa
Change the man page generation to asciidoc, because it's easier to use and has been more commonly used in related projects. Remove the current rst pages. Add 3 man pages to have a base for more additions: libperf.3 - overall description libperf-counting.7 - counting basics explained on simple example libperf-sampling.7 - sampling basics explained on simple example The plan is to add more man pages to cover the basic API. The build generates html and man pages: $ cd tools/lib/perf/Documentation $ make ASCIIDOC libperf.xml XMLTO libperf.3 ASCIIDOC libperf-counting.xml XMLTO libperf-counting.7 ASCIIDOC libperf-sampling.xml XMLTO libperf-sampling.7 ASCIIDOC libperf.html ASCIIDOC libperf-counting.html ASCIIDOC libperf-sampling.html Add the following install targets: install-man - man pages install-html - html version of man pages install-examples - examples mentioned in the man pages Signed-off-by: Jiri Olsa <jolsa@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20191206210612.8676-3-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2020-01-06libperf: Move to tools/lib/perfJiri Olsa
Move libperf from its current location under tools/perf to a separate directory under tools/lib/. Also change various paths (mainly includes) to reflect the libperf move to a separate directory and add a new directory under MANIFEST. Signed-off-by: Jiri Olsa <jolsa@kernel.org> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Michael Petlan <mpetlan@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lore.kernel.org/lkml/20191206210612.8676-2-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>