9fbc61f832
The PMU capabilities information, which is located at /sys/bus/event_source/devices/<dev>/caps, is required by perf tool. For example, the max LBR information is required to stitch LBR call stack. Add perf_pmu__caps_parse() to parse the PMU capabilities information. The information is stored in a list. The following patch will store the capabilities information in perf header. Committer notes: Here's an example of such directories and its files in an i5 7th gen machine: [root@seventh ~]# ls -lad /sys/bus/event_source/devices/*/caps drwxr-xr-x. 2 root root 0 Apr 14 13:33 /sys/bus/event_source/devices/cpu/caps drwxr-xr-x. 2 root root 0 Apr 14 13:33 /sys/bus/event_source/devices/intel_pt/caps [root@seventh ~]# ls -la /sys/bus/event_source/devices/intel_pt/caps total 0 drwxr-xr-x. 2 root root 0 Apr 14 13:33 . drwxr-xr-x. 5 root root 0 Apr 14 13:12 .. -r--r--r--. 1 root root 4096 Apr 16 13:10 cr3_filtering -r--r--r--. 1 root root 4096 Apr 16 11:42 cycle_thresholds -r--r--r--. 1 root root 4096 Apr 16 13:10 ip_filtering -r--r--r--. 1 root root 4096 Apr 16 13:10 max_subleaf -r--r--r--. 1 root root 4096 Apr 14 13:33 mtc -r--r--r--. 1 root root 4096 Apr 14 13:33 mtc_periods -r--r--r--. 1 root root 4096 Apr 16 13:10 num_address_ranges -r--r--r--. 1 root root 4096 Apr 16 13:10 output_subsys -r--r--r--. 1 root root 4096 Apr 16 13:10 payloads_lip -r--r--r--. 1 root root 4096 Apr 16 13:10 power_event_trace -r--r--r--. 1 root root 4096 Apr 14 13:33 psb_cyc -r--r--r--. 1 root root 4096 Apr 14 13:33 psb_periods -r--r--r--. 1 root root 4096 Apr 16 13:10 ptwrite -r--r--r--. 1 root root 4096 Apr 16 13:10 single_range_output -r--r--r--. 1 root root 4096 Apr 16 12:03 topa_multiple_entries -r--r--r--. 1 root root 4096 Apr 16 13:10 topa_output [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/topa_output 1 [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/topa_multiple_entries 1 [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/mtc 1 [root@seventh ~]# cat /sys/bus/event_source/devices/intel_pt/caps/power_event_trace 0 [root@seventh ~]# [root@seventh ~]# ls -la /sys/bus/event_source/devices/cpu/caps/ total 0 drwxr-xr-x. 2 root root 0 Apr 14 13:33 . drwxr-xr-x. 6 root root 0 Apr 14 13:12 .. -r--r--r--. 1 root root 4096 Apr 16 13:10 branches -r--r--r--. 1 root root 4096 Apr 14 13:33 max_precise -r--r--r--. 1 root root 4096 Apr 16 13:10 pmu_name [root@seventh ~]# cat /sys/bus/event_source/devices/cpu/caps/max_precise 3 [root@seventh ~]# cat /sys/bus/event_source/devices/cpu/caps/branches 32 [root@seventh ~]# cat /sys/bus/event_source/devices/cpu/caps/pmu_name skylake [root@seventh ~]# Wow, first time I've heard about /sys/bus/event_source/devices/cpu/caps/max_precise, I think I'll use it! :-) Signed-off-by: Kan Liang <kan.liang@linux.intel.com> Reviewed-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@redhat.com> Cc: Adrian Hunter <adrian.hunter@intel.com> Cc: Alexey Budankov <alexey.budankov@linux.intel.com> Cc: Mathieu Poirier <mathieu.poirier@linaro.org> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Pavel Gerasimov <pavel.gerasimov@intel.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com> Cc: Stephane Eranian <eranian@google.com> Cc: Vitaly Slobodskoy <vitaly.slobodskoy@intel.com> Link: http://lore.kernel.org/lkml/20200319202517.23423-2-kan.liang@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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.