Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751310Ab3GXC0z (ORCPT ); Tue, 23 Jul 2013 22:26:55 -0400 Received: from ozlabs.org ([203.10.76.45]:53808 "EHLO ozlabs.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750864Ab3GXC0y (ORCPT ); Tue, 23 Jul 2013 22:26:54 -0400 From: Michael Ellerman To: Cc: acme@ghostprotocols.net, a.p.zijlstra@chello.nl, mingo@redhat.com, Paul Mackerras , Anton Blanchard Subject: [PATCH] perf tools: Add support for pinned modifier Date: Wed, 24 Jul 2013 12:26:42 +1000 Message-Id: <1374632802-15436-1-git-send-email-michael@ellerman.id.au> X-Mailer: git-send-email 1.8.1.2 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4172 Lines: 118 This commit adds support for a new modifier "P", which requests that the event, or group of events, be pinned to the PMU. This is an oft-requested feature from our HW folks, who want to be able to run a large number of events, but also want 100% accurate results for instructions per cycle. Comparison of results with and without pinning: $ perf stat -e '{cycles,instructions}:P' -e cycles,instructions,... 79,590,480,683 cycles # 0.000 GHz 166,123,716,524 instructions # 2.09 insns per cycle # 0.11 stalled cycles per insn 79,352,134,463 cycles # 0.000 GHz [11.11%] 165,178,301,818 instructions # 2.08 insns per cycle # 0.11 stalled cycles per insn [11.13%] As you can see although perf does a very good job of scaling the values in the non-pinned case, there is some small discrepancy. The patch is fairly straight forward, the one detail is that we need to make sure we only request pinning for the group leader when we have a group. Signed-off-by: Michael Ellerman --- I would have used "p" obviously, but that's taken. Are folks happy that "P" is sufficiently different from "p"? I couldn't think of anything better. --- tools/perf/Documentation/perf-list.txt | 1 + tools/perf/util/parse-events.c | 9 +++++++++ tools/perf/util/parse-events.l | 2 +- 3 files changed, 11 insertions(+), 1 deletion(-) diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt index 826f3d6..7ecf655 100644 --- a/tools/perf/Documentation/perf-list.txt +++ b/tools/perf/Documentation/perf-list.txt @@ -29,6 +29,7 @@ counted. The following modifiers exist: G - guest counting (in KVM guests) H - host counting (not in KVM guests) p - precise level + P - pin the event to the PMU The 'p' modifier can be used for specifying how precise the instruction address should be. The 'p' modifier can be specified multiple times: diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c index 2c460ed..962093a 100644 --- a/tools/perf/util/parse-events.c +++ b/tools/perf/util/parse-events.c @@ -687,6 +687,7 @@ struct event_modifier { int eG; int precise; int exclude_GH; + int pinned; }; static int get_event_modifier(struct event_modifier *mod, char *str, @@ -698,6 +699,7 @@ static int get_event_modifier(struct event_modifier *mod, char *str, int eH = evsel ? evsel->attr.exclude_host : 0; int eG = evsel ? evsel->attr.exclude_guest : 0; int precise = evsel ? evsel->attr.precise_ip : 0; + int pinned = evsel ? evsel->attr.pinned : 0; int exclude = eu | ek | eh; int exclude_GH = evsel ? evsel->exclude_GH : 0; @@ -730,6 +732,8 @@ static int get_event_modifier(struct event_modifier *mod, char *str, /* use of precise requires exclude_guest */ if (!exclude_GH) eG = 1; + } else if (*str == 'P') { + pinned = 1; } else break; @@ -756,6 +760,8 @@ static int get_event_modifier(struct event_modifier *mod, char *str, mod->eG = eG; mod->precise = precise; mod->exclude_GH = exclude_GH; + mod->pinned = pinned; + return 0; } @@ -806,6 +812,9 @@ int parse_events__modifier_event(struct list_head *list, char *str, bool add) evsel->attr.exclude_host = mod.eH; evsel->attr.exclude_guest = mod.eG; evsel->exclude_GH = mod.exclude_GH; + + if (evsel->leader == evsel) + evsel->attr.pinned = mod.pinned; } return 0; diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l index e9d1134..587dac0 100644 --- a/tools/perf/util/parse-events.l +++ b/tools/perf/util/parse-events.l @@ -82,7 +82,7 @@ num_hex 0x[a-fA-F0-9]+ num_raw_hex [a-fA-F0-9]+ name [a-zA-Z_*?][a-zA-Z0-9_*?]* name_minus [a-zA-Z_*?][a-zA-Z0-9\-_*?]* -modifier_event [ukhpGH]+ +modifier_event [ukhpGHP]+ modifier_bp [rwx]{1,3} %% -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/