From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752451AbdGDTaW (ORCPT ); Tue, 4 Jul 2017 15:30:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:32772 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752406AbdGDTaS (ORCPT ); Tue, 4 Jul 2017 15:30:18 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DBD322C86 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org From: Arnaldo Carvalho de Melo To: Ingo Molnar Cc: linux-kernel@vger.kernel.org, Arnaldo Carvalho de Melo , Adrian Hunter , Andy Lutomirski , David Ahern , Jiri Olsa , Namhyung Kim , Wang Nan Subject: [PATCH 1/2] perf evsel: Set attr.exclude_kernel when probing max attr.precise_ip Date: Tue, 4 Jul 2017 16:29:59 -0300 Message-Id: <20170704193000.10555-2-acme@kernel.org> X-Mailer: git-send-email 2.9.4 In-Reply-To: <20170704193000.10555-1-acme@kernel.org> References: <20170704193000.10555-1-acme@kernel.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Arnaldo Carvalho de Melo We should set attr.exclude_kernel when probing for attr.precise_ip level, otherwise !CAP_SYS_ADMIN users will not default to skidless samples in capable hardware. The increase in the paranoid level in commit 0161028b7c8a ("perf/core: Change the default paranoia level to 2") broke this, fix it by excluding kernel samples when probing. Before: $ perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.018 MB perf.data (6 samples) ] $ perf evlist -v cycles:u: sample_freq: 4000, sample_type: IP|TID|TIME|PERIOD, exclude_kernel: 1 After: $ perf record usleep 1 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.018 MB perf.data (8 samples) ] $ perf evlist -v cycles:ppp: sample_freq: 4000, sample_type: IP|TID|TIME|PERIOD, exclude_kernel: 1, precise_ip: 3 ^^^^^^^^^^^^^ ^^^^^^^^^^^^^ ^^^^^^^^^^^^^ $ To further clarify: we always set .exclude_kernel when non !CAP_SYS_ADMIN users profile, its just on the attr.precise_ip probing that we weren't doing so, fix it. Cc: Adrian Hunter Cc: Andy Lutomirski Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Fixes: 7f8d1ade1b19 ("perf tools: By default use the most precise "cycles" hw counter available") Link: http://lkml.kernel.org/n/tip-t2qttwhbnua62o5gt75cueml@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/evsel.c | 1 + 1 file changed, 1 insertion(+) diff --git a/tools/perf/util/evsel.c b/tools/perf/util/evsel.c index cda44b0e821c..91192415f38d 100644 --- a/tools/perf/util/evsel.c +++ b/tools/perf/util/evsel.c @@ -269,6 +269,7 @@ struct perf_evsel *perf_evsel__new_cycles(void) struct perf_event_attr attr = { .type = PERF_TYPE_HARDWARE, .config = PERF_COUNT_HW_CPU_CYCLES, + .exclude_kernel = 1, }; struct perf_evsel *evsel; -- 2.9.4