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 X-Spam-Level: X-Spam-Status: No, score=-17.4 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT, USER_IN_DEF_DKIM_WL autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 11099C2D0F3 for ; Wed, 1 Apr 2020 23:40:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D893420842 for ; Wed, 1 Apr 2020 23:40:37 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="nq6MKW8v" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387460AbgDAXkg (ORCPT ); Wed, 1 Apr 2020 19:40:36 -0400 Received: from mail-ua1-f74.google.com ([209.85.222.74]:55791 "EHLO mail-ua1-f74.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387406AbgDAXke (ORCPT ); Wed, 1 Apr 2020 19:40:34 -0400 Received: by mail-ua1-f74.google.com with SMTP id u3so508097uau.22 for ; Wed, 01 Apr 2020 16:40:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=fw+yQGCuc66qsKCfiv8tB1DIU00RCb9NXGODIc5CbC0=; b=nq6MKW8vjnHoYBrrSdgrb6aBTxh5KddIzu2+cqAx2OoMKkLD+wRnUXxzXIQimi/+a6 4mJoy8SbmZZ3TsRLZttKMCW5dr36evrm1pVnAOpHUUQbKcV74xvQH1HWrYJ/kooFxPNg PY8MPRvTYRDUutFZYQMT9CZrwpeS+Xq23fWt8D/yXCNr0jcM186DzC4tHon6PbCECHAa 31Jj8Ft/k0174vHBzQRTgF8sJj9sppQBujsrtc47DqepxZRJ3hv0cCxg/ytP5KeqXQzj jE9spyDT41erJsPEr0AW957Bm3biGat/1lzMTOxQg7ZtgUK3isnD8LvUHQVj+NkfKUMe VPhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=fw+yQGCuc66qsKCfiv8tB1DIU00RCb9NXGODIc5CbC0=; b=MdkSTNwdqo5cMsRaFGw80uUHvpjbWLp8GWPJNtpLXBPYTsofNQ/4fWSEWnywLHQsKW o/Wy7rqUXNhGy4yGtXBOVQXhpqbs/titY/jGPnwRR+kf6QLHlR10dqYGwhSCLh0iC5Al j8HZT2g9byLnSbRtxKJsjNwCVvWTyL1YSHst4aCBweEYKpCke1jHNDRwiPumAKtkwogr xh3SCHMuqkZ3gxeE2DnJ3jTwq5wUSFOxPAEIqR5V5h1yG4knUluo/v92whcG/Nr9E017 eMpEMX2UPZykHFQusYWOAT2SwAXWsEl+f2TowiGlP1AdPrI4YavHV1szzE5NHrXoqZCN 3u/A== X-Gm-Message-State: AGi0PuYByQl+UZgv9L5d+meriLtkzWPQc/ZpjFJTB/nCr8T6HJ5MggGw MLV+GPL+WqciQqZtvN9cM1tVYPw/8MdC X-Google-Smtp-Source: APiQypKQvIHLrjwvEpYASJdHdxgbmPDO3zEzH/O+p7qQIf12N1bBJDDBy1z77NKJwFa4iDlbqyR7DzlT8sXH X-Received: by 2002:a67:7f8a:: with SMTP id a132mr309716vsd.147.1585784432486; Wed, 01 Apr 2020 16:40:32 -0700 (PDT) Date: Wed, 1 Apr 2020 16:39:43 -0700 In-Reply-To: <20200401233945.133550-1-irogers@google.com> Message-Id: <20200401233945.133550-4-irogers@google.com> Mime-Version: 1.0 References: <20200401233945.133550-1-irogers@google.com> X-Mailer: git-send-email 2.26.0.rc2.310.g2932bb562d-goog Subject: [PATCH 3/5] perf synthetic-events: save 4kb from 2 stack frames From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Petr Mladek , Andrey Zhizhikin , Kefeng Wang , Thomas Gleixner , Kan Liang , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org Cc: Stephane Eranian , Ian Rogers Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Reuse an existing char buffer to avoid two PATH_MAX sized char buffers. Reduces stack frame sizes by 4kb. perf_event__synthesize_mmap_events before 'sub $0x45b8,%rsp' after 'sub $0x35b8,%rsp'. perf_event__get_comm_ids before 'sub $0x2028,%rsp' after 'sub $0x1028,%rsp'. The performance impact of this change is negligible. Signed-off-by: Ian Rogers --- tools/perf/util/synthetic-events.c | 22 ++++++++++------------ 1 file changed, 10 insertions(+), 12 deletions(-) diff --git a/tools/perf/util/synthetic-events.c b/tools/perf/util/synthetic-events.c index 3f28af39f9c6..1f3d8d4bb879 100644 --- a/tools/perf/util/synthetic-events.c +++ b/tools/perf/util/synthetic-events.c @@ -70,7 +70,6 @@ int perf_tool__process_synth_event(struct perf_tool *tool, static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len, pid_t *tgid, pid_t *ppid) { - char filename[PATH_MAX]; char bf[4096]; int fd; size_t size = 0; @@ -80,11 +79,11 @@ static int perf_event__get_comm_ids(pid_t pid, char *comm, size_t len, *tgid = -1; *ppid = -1; - snprintf(filename, sizeof(filename), "/proc/%d/status", pid); + snprintf(bf, sizeof(bf), "/proc/%d/status", pid); - fd = open(filename, O_RDONLY); + fd = open(bf, O_RDONLY); if (fd < 0) { - pr_debug("couldn't open %s\n", filename); + pr_debug("couldn't open %s\n", bf); return -1; } @@ -280,9 +279,9 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, struct machine *machine, bool mmap_data) { - char filename[PATH_MAX]; FILE *fp; unsigned long long t; + char bf[BUFSIZ]; bool truncation = false; unsigned long long timeout = proc_map_timeout * 1000000ULL; int rc = 0; @@ -292,15 +291,15 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, if (machine__is_default_guest(machine)) return 0; - snprintf(filename, sizeof(filename), "%s/proc/%d/task/%d/maps", - machine->root_dir, pid, pid); + snprintf(bf, sizeof(bf), "%s/proc/%d/task/%d/maps", + machine->root_dir, pid, pid); - fp = fopen(filename, "r"); + fp = fopen(bf, "r"); if (fp == NULL) { /* * We raced with a task exiting - just return: */ - pr_debug("couldn't open %s\n", filename); + pr_debug("couldn't open %s\n", bf); return -1; } @@ -308,7 +307,6 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, t = rdclock(); while (1) { - char bf[BUFSIZ]; char prot[5]; char execname[PATH_MAX]; char anonstr[] = "//anon"; @@ -320,10 +318,10 @@ int perf_event__synthesize_mmap_events(struct perf_tool *tool, break; if ((rdclock() - t) > timeout) { - pr_warning("Reading %s time out. " + pr_warning("Reading %s/proc/%d/task/%d/maps time out. " "You may want to increase " "the time limit by --proc-map-timeout\n", - filename); + machine->root_dir, pid, pid); truncation = true; goto out; } -- 2.26.0.rc2.310.g2932bb562d-goog