From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Google-Smtp-Source: AG47ELuAPhd4ULXlm+hH9nbVJprgksAVyotBPJUf4bgnj/vWCRnE2mbMpqz1TssxI4lYf+VsRBRb ARC-Seal: i=1; a=rsa-sha256; t=1521483532; cv=none; d=google.com; s=arc-20160816; b=cCvP58jkA8Mc2B6PPxgjKmRL0n2/Tx4eLW15ZwzzLIoMseGWOf4eaGT/ceNaR9CQPH ScjrD6qFejX3Q2c+kw2vdAkgef0RTfyWzh7Ciww62Yf89QSaoYRoiyXDanHNg2AglQkE f0WJVAeMAMZ+meFJJOr0V7JRpVc9k6qxivB/Jayc+fSq51rDq5GOKkIZaeiNnGZCMrO1 5AJb3InzJjzWlWCfFfV+a3vjiQtl4tk2EN6UNDMrdOxS43kHclHjgidgNKHUNkFDF0xP 58DsuJlx1ps2bsm9Su6aJQOJdujsdzTM3lX4N23MntRI0uy+X7FODf7+fEDfSOVSCB27 p4aw== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=mime-version:user-agent:references:in-reply-to:message-id:date :subject:cc:to:from:arc-authentication-results; bh=XkqPXvpWNns8/CzQ8nhiEgkgjiDYaO3PCMJxh7ImzxM=; b=tTTG469jwdW+y/SaCNLOpRuqiCVk/Iq9ZSWYtWzPIIhTcDuQMCdXfBzE1FMiJNwKCB 4ypC5/7ftEDMZCVGfiLo08NweTZTjGYOJBXtMFsZ+HIQig1FGRhXO6no1tzCirSGqF4I pWUYvxQgoGrSOHgBQPnTaqzhPeYVbN1D3Wh+6ucSN6L3AgHspe4Qh+08e0U2oCpi6sHA pF4OztL6sjiIb10tcw1jP/kZWHsNt4w/FiWxJMwI4AMJN1uk5olYpT7qp/88kxkZuyJw gc3dHDbiPBQwAZvjTq7cSftyNPgbo1K0slj+xOVwbjk6x21W6B8DRhBvaO1cOjxXnNzC QTog== ARC-Authentication-Results: i=1; mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org Authentication-Results: mx.google.com; spf=softfail (google.com: domain of transitioning gregkh@linuxfoundation.org does not designate 90.92.61.202 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Borislav Petkov , Ingo Molnar , Arnaldo Carvalho de Melo , Peter Zijlstra , Robert Richter , Vince Weaver , Sasha Levin Subject: [PATCH 4.9 003/241] perf stat: Issue a HW watchdog disable hint Date: Mon, 19 Mar 2018 19:04:28 +0100 Message-Id: <20180319180751.316243264@linuxfoundation.org> X-Mailer: git-send-email 2.16.2 In-Reply-To: <20180319180751.172155436@linuxfoundation.org> References: <20180319180751.172155436@linuxfoundation.org> User-Agent: quilt/0.65 X-stable: review MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 X-getmail-retrieved-from-mailbox: INBOX X-GMAIL-LABELS: =?utf-8?b?IlxcU2VudCI=?= X-GMAIL-THRID: =?utf-8?q?1595391116141665242?= X-GMAIL-MSGID: =?utf-8?q?1595391116141665242?= X-Mailing-List: linux-kernel@vger.kernel.org List-ID: 4.9-stable review patch. If anyone has any objections, please let me know. ------------------ From: Borislav Petkov [ Upstream commit 02d492e5dcb72c004d213756eb87c9d62a6d76a7 ] When using perf stat on an AMD F15h system with the default hw events attributes, some of the events don't get counted: Performance counter stats for 'sleep 1': 0.749208 task-clock (msec) # 0.001 CPUs utilized 1 context-switches # 0.001 M/sec 0 cpu-migrations # 0.000 K/sec 54 page-faults # 0.072 M/sec 1,122,815 cycles # 1.499 GHz 286,740 stalled-cycles-frontend # 25.54% frontend cycles idle stalled-cycles-backend (0.00%) ^^^^^^^^^^^^ instructions (0.00%) ^^^^^^^^^^^^ branches (0.00%) branch-misses (0.00%) 1.001550070 seconds time elapsed The reason is that we have the HW watchdog consuming one PMU counter and when perf tries to schedule 6 events on 6 counters and some of those counters are constrained to only a specific subset of PMCs by the hardware, the event scheduling fails. So issue a hint to disable the HW watchdog around a perf stat session. Committer note: Testing it... # perf stat -d usleep 1 Performance counter stats for 'usleep 1': 1.180203 task-clock (msec) # 0.490 CPUs utilized 1 context-switches # 0.847 K/sec 0 cpu-migrations # 0.000 K/sec 54 page-faults # 0.046 M/sec 184,754 cycles # 0.157 GHz 714,553 instructions # 3.87 insn per cycle 154,661 branches # 131.046 M/sec 7,247 branch-misses # 4.69% of all branches 219,984 L1-dcache-loads # 186.395 M/sec 17,600 L1-dcache-load-misses # 8.00% of all L1-dcache hits (90.16%) LLC-loads (0.00%) LLC-load-misses (0.00%) 0.002406823 seconds time elapsed Some events weren't counted. Try disabling the NMI watchdog: echo 0 > /proc/sys/kernel/nmi_watchdog perf stat ... echo 1 > /proc/sys/kernel/nmi_watchdog # Signed-off-by: Borislav Petkov Acked-by: Ingo Molnar Tested-by: Arnaldo Carvalho de Melo Cc: Peter Zijlstra Cc: Robert Richter Cc: Vince Weaver Link: http://lkml.kernel.org/r/20170211183218.ijnvb5f7ciyuunx4@pd.tnic Signed-off-by: Arnaldo Carvalho de Melo Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- tools/perf/builtin-stat.c | 11 +++++++++++ 1 file changed, 11 insertions(+) --- a/tools/perf/builtin-stat.c +++ b/tools/perf/builtin-stat.c @@ -146,6 +146,7 @@ static aggr_get_id_t aggr_get_id; static bool append_file; static const char *output_name; static int output_fd; +static int print_free_counters_hint; struct perf_stat { bool record; @@ -1109,6 +1110,9 @@ static void printout(int id, int nr, str counter->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED, csv_sep); + if (counter->supported) + print_free_counters_hint = 1; + fprintf(stat_config.output, "%-*s%s", csv_output ? 0 : unit_width, counter->unit, csv_sep); @@ -1477,6 +1481,13 @@ static void print_footer(void) avg_stats(&walltime_nsecs_stats)); } fprintf(output, "\n\n"); + + if (print_free_counters_hint) + fprintf(output, +"Some events weren't counted. Try disabling the NMI watchdog:\n" +" echo 0 > /proc/sys/kernel/nmi_watchdog\n" +" perf stat ...\n" +" echo 1 > /proc/sys/kernel/nmi_watchdog\n"); } static void print_counters(struct timespec *ts, int argc, const char **argv)