From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 5C8F2C4332F for ; Fri, 3 Nov 2023 09:45:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1347309AbjKCJpo (ORCPT ); Fri, 3 Nov 2023 05:45:44 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347166AbjKCJpn (ORCPT ); Fri, 3 Nov 2023 05:45:43 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.126]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5D009D42; Fri, 3 Nov 2023 02:45:37 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1699004737; x=1730540737; h=date:from:to:cc:subject:in-reply-to:message-id: references:mime-version; bh=vlF3S9N1W0zguAYvyFDi0DyELIRHNl9kTQEQgEsQL0U=; b=Ck1FEVDCFy/FLPoyGhxsCa8vnETcp/6CZOWRpLCE2umvjTNs8sGvG2NP Iru2eeVso5lRC+0mmjuU5ccPTvEh/PhwXw9QlMe4VSyFK1TF4AAx0fqqm Hw6Kdl7xnda2nFFYkDznu6pgTjMyHPO50ArcjzhaQcKvuiDBmdNMbfuTc xg+IiQPfqK14hfDCX4M2iy9Hxtce/GrgUgQiKcR5PMkjo1a9QD50IAgEu ZauwusiD4mes7FmDpvQ3r59C149Bg62XHLFzhzChraVcd36wLhLkQgoRN ZUc/FBuRNFWpeUUwok1HFuNu97YxmakPhrdYLVwStbIk+u+h18FF8O52K w==; X-IronPort-AV: E=McAfee;i="6600,9927,10882"; a="373955879" X-IronPort-AV: E=Sophos;i="6.03,273,1694761200"; d="scan'208";a="373955879" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Nov 2023 02:45:36 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10882"; a="790708773" X-IronPort-AV: E=Sophos;i="6.03,273,1694761200"; d="scan'208";a="790708773" Received: from pors-mobl3.ger.corp.intel.com ([10.252.35.38]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 03 Nov 2023 02:45:34 -0700 Date: Fri, 3 Nov 2023 11:45:31 +0200 (EET) From: =?ISO-8859-15?Q?Ilpo_J=E4rvinen?= To: Reinette Chatre cc: linux-kselftest@vger.kernel.org, Shuah Khan , Shaopeng Tan , =?ISO-8859-15?Q?Maciej_Wiecz=F3r-Retman?= , Fenghua Yu , LKML Subject: Re: [PATCH 10/24] selftests/resctrl: Remove nested calls in perf event handling In-Reply-To: <93113f94-9663-4cbb-962f-c415bc975f12@intel.com> Message-ID: References: <20231024092634.7122-1-ilpo.jarvinen@linux.intel.com> <20231024092634.7122-11-ilpo.jarvinen@linux.intel.com> <93113f94-9663-4cbb-962f-c415bc975f12@intel.com> MIME-Version: 1.0 Content-Type: multipart/mixed; boundary="8323329-935771429-1699004736=:1725" Precedence: bulk List-ID: X-Mailing-List: linux-kselftest@vger.kernel.org This message is in MIME format. The first part should be readable text, while the remaining parts are likely unreadable without MIME-aware tools. --8323329-935771429-1699004736=:1725 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8BIT On Thu, 2 Nov 2023, Reinette Chatre wrote: > Hi Ilpo, > > On 10/24/2023 2:26 AM, Ilpo Järvinen wrote: > > Perf event handling has functions that are the sole caller of another > > perf event handling related function: > > - reset_enable_llc_perf() calls perf_event_open_llc_miss() > > - reset_enable_llc_perf() calls ioctl_perf_event_ioc_reset_enable() > > - measure_llc_perf() calls get_llc_perf() > > > > Remove the extra layer of calls to make the code easier to follow by > > moving the code into the calling function. > > > > In addition, converts print_results_cache() unsigned long parameter to > > __u64 that matches the type coming from perf. > > Is this referring to work from previous patch? Yes, this got split into own patch and it unfortunately lingered on in the changelog. I'll remove it. > > Signed-off-by: Ilpo Järvinen --- > > > > 1 file changed, 25 insertions(+), 61 deletions(-) > > > > diff --git a/tools/testing/selftests/resctrl/cache.c b/tools/testing/selftests/resctrl/cache.c > > index d39ef4eebc37..208af1ecae28 100644 > > --- a/tools/testing/selftests/resctrl/cache.c > > +++ b/tools/testing/selftests/resctrl/cache.c > > -/* > > - * get_llc_perf: llc cache miss through perf events > > - * @llc_perf_miss: LLC miss counter that is filled on success > > - * > > - * Perf events like HW_CACHE_MISSES could be used to validate number of > > - * cache lines allocated. > > - * > > - * Return: =0 on success. <0 on failure. > > - */ > > -static int get_llc_perf(__u64 *llc_perf_miss) > > -{ > > - int ret; > > - > > - /* Stop counters after one span to get miss rate */ > > - > > - ioctl(fd_lm, PERF_EVENT_IOC_DISABLE, 0); > > - > > - ret = read(fd_lm, &rf_cqm, sizeof(struct read_format)); > > - if (ret == -1) { > > - perror("Could not get llc misses through perf"); > > + fd_lm = perf_event_open(&pea_llc_miss, pid, cpu_no, -1, PERF_FLAG_FD_CLOEXEC); > > + if (fd_lm == -1) { > > + perror("Error opening leader"); > > + ctrlc_handler(0, NULL, NULL); > > I understand you just copied the code here ... but it is not clear to me > why this particular error handling deserves a ctrlc_handler(). Good catch! It's first time I even notice this line. It certainly looks a bit too big hammer for error handling. I'll try to create a separate patch which properly removes it (I suspect all error handling rollbacks are there already so it can just be removed but I'll have to confirm that). > > return -1; > > } > > > > - *llc_perf_miss = rf_cqm.values[0].value; > > + /* Start counters to log values */ > > + ioctl(fd_lm, PERF_EVENT_IOC_RESET, 0); > > + ioctl(fd_lm, PERF_EVENT_IOC_ENABLE, 0); > > > > return 0; > > } > > @@ -166,20 +121,29 @@ static int print_results_cache(char *filename, int bm_pid, __u64 llc_value) > > return 0; > > } > > > > +/* > > + * measure_llc_perf: measure perf events > > + * @bm_pid: child pid that runs benchmark > > I expected "bm_pid" to reflect a "benchmark pid" that > is not unique to the child. Are both parent and child > not running the benchmark? > > Missing doc of a parameter here. > > > + * > > + * Measure things like cache misses from perf events. > > "things like cache misses" is vague. The function's name > still contains "llc" which makes me think it is not quite > generic yet. I suppose I tried to be intentionally vague because I knew I was going to use it measure also LLC accesses in the case of L2 CAT test. I'll see if I can improve this wording somehow. > > + * > > + * Return: =0 on success. <0 on failure. > > + */ > > static int measure_llc_perf(struct resctrl_val_param *param, int bm_pid) > > { > > - __u64 llc_perf_miss = 0; > > int ret; > > > > - /* > > - * Measure cache miss from perf. > > - */ > > - ret = get_llc_perf(&llc_perf_miss); > > - if (ret < 0) > > - return ret; > > + /* Stop counters after one span to get miss rate */ > > + ioctl(fd_lm, PERF_EVENT_IOC_DISABLE, 0); > > > > - ret = print_results_cache(param->filename, bm_pid, llc_perf_miss); > > - return ret; > > + ret = read(fd_lm, &rf_cqm, sizeof(struct read_format)); > > + close(fd_lm); > > I am not able to tell where this close() moved from. Another good catch. It seems to be a conflict resolution fallout from the time when I changed to close() logic in that fix patch related to this fd. -- i. --8323329-935771429-1699004736=:1725--