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[ Upstream commitecc68ee216] It seems that perf stat -b <prog id> doesn't produce any results: $ perf stat -e cycles -b 4 -I 10000 -vvv Control descriptor is not initialized cycles: 0 0 0 time counts unit events 10.007641640 <not supported> cycles Looks like this happens because fentry/fexit progs are getting loaded, but the corresponding perf event is not enabled and not added into the events bpf map. I think there is some mixing up between two type of bpf support, one for bperf and one for bpf_profiler. Both are identified via evsel__is_bpf, based on which perf events are enabled, but for the latter (bpf_profiler) a perf event is required. Using evsel__is_bperf to check only bperf produces expected results: $ perf stat -e cycles -b 4 -I 10000 -vvv Control descriptor is not initialized ------------------------------------------------------------ perf_event_attr: size 136 sample_type IDENTIFIER read_format TOTAL_TIME_ENABLED|TOTAL_TIME_RUNNING disabled 1 exclude_guest 1 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 = 3 ------------------------------------------------------------ [...perf_event_attr for other CPUs...] ------------------------------------------------------------ cycles: 309426 169009 169009 time counts unit events 10.010091271 309426 cycles The final numbers correspond (at least in the level of magnitude) to the same metric obtained via bpftool. Fixes:112cb56164("perf stat: Introduce config stat.bpf-counter-events") Reviewed-by: Song Liu <song@kernel.org> Signed-off-by: Dmitrii Dolgov <9erthalion6@gmail.com> Tested-by: Song Liu <song@kernel.org> Cc: Ian Rogers <irogers@google.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Song Liu <song@kernel.org> Link: https://lore.kernel.org/r/20230412182316.11628-1-9erthalion6@gmail.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.