linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2021-07-01	perf bpf_counter: Move common functions to bpf_counter.h	Namhyung Kim	1	-0/+52
	Some helper functions will be used for cgroup counting too. Move them to a header file for sharing. Committer notes: Fix the build on older systems with: - struct bpf_map_info map_info = {0}; + struct bpf_map_info map_info = { .id = 0, }; This wasn't breaking the build in such systems as bpf_counter.c isn't built due to: tools/perf/util/Build: perf-$(CONFIG_PERF_BPF_SKEL) += bpf_counter.o The bpf_counter.h file on the other hand is included from places that are built everywhere. Signed-off-by: Namhyung Kim <namhyung@kernel.org> Acked-by: Song Liu <songliubraving@fb.com> Cc: Andi Kleen <ak@linux.intel.com> Cc: Ian Rogers <irogers@google.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20210625071826.608504-4-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-04-29	perf stat: Introduce bpf_counter_ops->disable()	Song Liu	1	-0/+7
	Introduce bpf_counter_ops->disable(), which is used stop counting the event. Committer notes: Added a dummy bpf_counter__disable() to the python binding to avoid having 'perf test python' failing. bpf_counter isn't supported in the python binding. Signed-off-by: Song Liu <song@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Song Liu <songliubraving@fb.com> Cc: kernel-team@fb.com Link: https://lore.kernel.org/r/20210425214333.1090950-6-song@kernel.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-03-06	perf bpf: Minor whitespace cleanup.	Ian Rogers	1	-1/+1
	Missed space after #include. Signed-off-by: Ian Rogers <irogers@google.com> Acked-by: Song Liu <songliubraving@fb.com> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Stephane Eranian <eranian@google.com> Link: http://lore.kernel.org/lkml/20210306080840.3785816-3-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
2021-01-20	perf stat: Enable counting events for BPF programs	Song Liu	1	-0/+72
	Introduce 'perf stat -b' option, which counts events for BPF programs, like: [root@localhost ~]# ~/perf stat -e ref-cycles,cycles -b 254 -I 1000 1.487903822 115,200 ref-cycles 1.487903822 86,012 cycles 2.489147029 80,560 ref-cycles 2.489147029 73,784 cycles 3.490341825 60,720 ref-cycles 3.490341825 37,797 cycles 4.491540887 37,120 ref-cycles 4.491540887 31,963 cycles The example above counts 'cycles' and 'ref-cycles' of BPF program of id 254. This is similar to bpftool-prog-profile command, but more flexible. 'perf stat -b' creates per-cpu perf_event and loads fentry/fexit BPF programs (monitor-progs) to the target BPF program (target-prog). The monitor-progs read perf_event before and after the target-prog, and aggregate the difference in a BPF map. Then the user space reads data from these maps. A new 'struct bpf_counter' is introduced to provide a common interface that uses BPF programs/maps to count perf events. Committer notes: Removed all but bpf_counter.h includes from evsel.h, not needed at all. Also BPF map lookups for PERCPU_ARRAYs need to have as its value receive buffer passed to the kernel libbpf_num_possible_cpus() entries, not evsel__nr_cpus(evsel), as the former uses /sys/devices/system/cpu/possible while the later uses /sys/devices/system/cpu/online, which may be less than the 'possible' number making the bpf map lookup overwrite memory and cause hard to debug memory corruption. We need to continue using evsel__nr_cpus(evsel) when accessing the perf_counts array tho, not to overwrite another are of memory :-) Signed-off-by: Song Liu <songliubraving@fb.com> Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com> Link: https://lore.kernel.org/lkml/20210120163031.GU12699@kernel.org/ Acked-by: Namhyung Kim <namhyung@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: kernel-team@fb.com Link: http://lore.kernel.org/lkml/20201229214214.3413833-4-songliubraving@fb.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>