From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mgamail.intel.com (mgamail.intel.com [192.198.163.10]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 07D8C2BEC2C; Wed, 12 Nov 2025 08:20:51 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=192.198.163.10 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762935653; cv=none; b=XjLILVao3Kz/SAnsKcCwFDJGUQ6NO1IUoUb/SLUS13VbqgwPzqWO8ojE67Dvul+mvqLSkqHLE7uKee9F9Q+IgTnfv4Un5x/lmrQAF9mwjdc740urxK03UoPuzPLyjg0RSjY8MS/+v0SnGmM3ZAqiaUAlg222N39Rg5H95ultcXI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1762935653; c=relaxed/simple; bh=tDovnU/F87QjMyIAitrnddCeo2J61Wr57VXrCYCk5Bo=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=UI0NKFVBpPXXCFHkPUuB0NI1ktXfmnt0+kD0QuEx6VxvoyCwEBull8IgIik9oodHW0tO3SIufEIxzhp24aIoUx/TsxrxVAdAPmKonuIpbLOZ2cBQ21C7ryUQtG/ZQYSVM4NOrAJyl3Flx+Aur6H6aZzcP7WEqqzAo3/u148oZZ4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com; spf=pass smtp.mailfrom=linux.intel.com; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b=e1XxyZsi; arc=none smtp.client-ip=192.198.163.10 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.intel.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=intel.com header.i=@intel.com header.b="e1XxyZsi" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1762935652; x=1794471652; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=tDovnU/F87QjMyIAitrnddCeo2J61Wr57VXrCYCk5Bo=; b=e1XxyZsiVwuKX3gAZCJ6id3qEGtN/IrJGXaSbfkmMcVXa1DM7lGXFfGe Ntx0LaLzECTtzvosQoNpbNuFtJ5CExNp5yl9PajH7O6Q7S9aqSKaxo+cL 5Mg8+HsH7XIstefmwP4mNiMi1Ljm3wMIuF6RFOnPSZ3/5TksAJhaIVxq3 xkzdrgVIdO5NkZIS6w/h4bPu5eQG51MpPPUz4q64VXVQLx9DRbHGwdcC9 yGsX8wE/LGsj6P8G78zmaP+ihQBm1Ckf7/ShMTP8bvfw28DmMkZXt1uAO 3mOGAdeW51roCKuyommO1tMcj02wYTBdxl0SfWhDu28KIa6aY5xHjJj2q w==; X-CSE-ConnectionGUID: CWRWk52vQ96OFnFuQtOymg== X-CSE-MsgGUID: wjZ7QCQvTRatNBeK1IEgNw== X-IronPort-AV: E=McAfee;i="6800,10657,11610"; a="76342846" X-IronPort-AV: E=Sophos;i="6.19,298,1754982000"; d="scan'208";a="76342846" Received: from fmviesa004.fm.intel.com ([10.60.135.144]) by fmvoesa104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Nov 2025 00:20:51 -0800 X-CSE-ConnectionGUID: hEXvl5iUS8yuNL7za2zs1w== X-CSE-MsgGUID: nQFEgVN8TxaYi7k8/rZa7g== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="6.19,298,1754982000"; d="scan'208";a="194135950" Received: from unknown (HELO [10.238.3.175]) ([10.238.3.175]) by fmviesa004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 12 Nov 2025 00:20:46 -0800 Message-ID: Date: Wed, 12 Nov 2025 16:20:44 +0800 Precedence: bulk X-Mailing-List: linux-perf-users@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v4 00/18] To: Ian Rogers , Namhyung Kim Cc: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Alexander Shishkin , Jiri Olsa , Adrian Hunter , James Clark , Xu Yang , Chun-Tse Shao , Thomas Richter , Sumanth Korikkar , Collin Funk , Thomas Falcon , Howard Chu , Levi Yun , Yang Li , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Andi Kleen , Weilin Wang References: <20251111212206.631711-1-irogers@google.com> Content-Language: en-US From: "Mi, Dapeng" In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit On 11/12/2025 7:13 AM, Ian Rogers wrote: > On Tue, Nov 11, 2025 at 2:42 PM Namhyung Kim wrote: >> On Tue, Nov 11, 2025 at 01:21:48PM -0800, Ian Rogers wrote: >>> Prior to this series stat-shadow would produce hard coded metrics if >>> certain events appeared in the evlist. This series produces equivalent >>> json metrics and cleans up the consequences in tests and display >>> output. A before and after of the default display output on a >>> tigerlake is: >>> >>> Before: >>> ``` >>> $ perf stat -a sleep 1 >>> >>> Performance counter stats for 'system wide': >>> >>> 16,041,816,418 cpu-clock # 15.995 CPUs utilized >>> 5,749 context-switches # 358.376 /sec >>> 121 cpu-migrations # 7.543 /sec >>> 1,806 page-faults # 112.581 /sec >>> 825,965,204 instructions # 0.70 insn per cycle >>> 1,180,799,101 cycles # 0.074 GHz >>> 168,945,109 branches # 10.532 M/sec >>> 4,629,567 branch-misses # 2.74% of all branches >>> # 30.2 % tma_backend_bound >>> # 7.8 % tma_bad_speculation >>> # 47.1 % tma_frontend_bound >>> # 14.9 % tma_retiring >>> ``` >>> >>> After: >>> ``` >>> $ perf stat -a sleep 1 >>> >>> Performance counter stats for 'system wide': >>> >>> 2,890 context-switches # 179.9 cs/sec cs_per_second >>> 16,061,923,339 cpu-clock # 16.0 CPUs CPUs_utilized >>> 43 cpu-migrations # 2.7 migrations/sec migrations_per_second >>> 5,645 page-faults # 351.5 faults/sec page_faults_per_second >>> 5,708,413 branch-misses # 1.4 % branch_miss_rate (88.83%) >>> 429,978,120 branches # 26.8 M/sec branch_frequency (88.85%) >>> 1,626,915,897 cpu-cycles # 0.1 GHz cycles_frequency (88.84%) >>> 2,556,805,534 instructions # 1.5 instructions insn_per_cycle (88.86%) >>> TopdownL1 # 20.1 % tma_backend_bound >>> # 40.5 % tma_bad_speculation (88.90%) >>> # 17.2 % tma_frontend_bound (78.05%) >>> # 22.2 % tma_retiring (88.89%) >>> >>> 1.002994394 seconds time elapsed >>> ``` >>> >>> Having the metrics in json brings greater uniformity, allows events to >>> be shared by metrics, and it also allows descriptions like: >>> ``` >>> $ perf list cs_per_second >>> ... >>> cs_per_second >>> [Context switches per CPU second] >>> ``` >>> >>> A thorn in the side of doing this work was that the hard coded metrics >>> were used by perf script with '-F metric'. This functionality didn't >>> work for me (I was testing `perf record -e instructions,cycles` >>> with/without leader sampling and then `perf script -F metric` but saw >>> nothing but empty lines) but anyway I decided to fix it to the best of >>> my ability in this series. So the script side counters were removed >>> and the regular ones associated with the evsel used. The json metrics >>> were all searched looking for ones that have a subset of events >>> matching those in the perf script session, and all metrics are >>> printed. This is kind of weird as the counters are being set by the >>> period of samples, but I carried the behavior forward. I suspect there >>> needs to be follow up work to make this better, but what is in the >>> series is superior to what is currently in the tree. Follow up work >>> could include finding metrics for the machine in the perf.data rather >>> than using the host, allowing multiple metrics even if the metric ids >>> of the events differ, fixing pre-existing `perf stat record/report` >>> issues, etc. >>> >>> There is a lot of stat tests that, for example, assume '-e >>> instructions,cycles' will produce an IPC metric. These things needed >>> tidying as now the metric must be explicitly asked for and when doing >>> this ones using software events were preferred to increase >>> compatibility. As the test updates were numerous they are distinct to >>> the patches updating the functionality causing periods in the series >>> where not all tests are passing. If this is undesirable the test fixes >>> can be squashed into the functionality updates, but this will be kind >>> of messy, especially as at some points in the series both the old >>> metrics and the new metrics will be displayed. >>> >>> v4: K/sec to M/sec on branch frequency (Namhyung), perf script -F >>> metric to-done a system-wide calculation (Namhyung) and don't >>> crash because of the CPU map index couldn't be found. Regenerate >>> commit messages but the cpu-clock was always yielding 0 on my >>> machine leading to a lot of nan metric values. >> This is strange. The cpu-clock should not be 0 as long as you ran it. >> Do you think it's related to the scale unit change? I tested v3 and >> didn't see the problem. > It looked like a kernel issue. The raw counts were 0 before being > scaled. All metrics always work on unscaled values. It is only the > commit messages and the formatting is more important than the numeric > values - which were correct for a cpu-clock of 0. Yes, It's a kernel issue. I also found it several days ago. I have posted a patch to fix it. :) https://lore.kernel.org/all/20251112080526.3971392-1-dapeng1.mi@linux.intel.com/ > > Thanks, > Ian >