From 4ca0d8193f8b6b2c74d05d9bbcbaa99fdd553503 Mon Sep 17 00:00:00 2001 From: Andi Kleen <ak@linux.intel.com> Date: Mon, 21 Mar 2016 08:56:33 -0700 Subject: [PATCH] perf list: Fix documentation of :ppp Correctly document what is implemented for :ppp on Intel CPUs in recent kernels. Signed-off-by: Andi Kleen <ak@linux.intel.com> Acked-by: Jiri Olsa <jolsa@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/1458575793-12091-2-git-send-email-andi@firstfloor.org Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com> --- tools/perf/Documentation/perf-list.txt | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt index 79483f40e991e..ec723d0a5bb3f 100644 --- a/tools/perf/Documentation/perf-list.txt +++ b/tools/perf/Documentation/perf-list.txt @@ -40,10 +40,12 @@ address should be. The 'p' modifier can be specified multiple times: 0 - SAMPLE_IP can have arbitrary skid 1 - SAMPLE_IP must have constant skid 2 - SAMPLE_IP requested to have 0 skid - 3 - SAMPLE_IP must have 0 skid + 3 - SAMPLE_IP must have 0 skid, or uses randomization to avoid + sample shadowing effects. For Intel systems precise event sampling is implemented with PEBS -which supports up to precise-level 2. +which supports up to precise-level 2, and precise level 3 for +some special cases On AMD systems it is implemented using IBS (up to precise-level 2). The precise modifier works with event types 0x76 (cpu-cycles, CPU -- 2.30.2