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 38CB5C4332B for ; Sat, 21 Mar 2020 00:14:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id EF25820753 for ; Sat, 21 Mar 2020 00:14:06 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="c+fFGjuk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727499AbgCUAOF (ORCPT ); Fri, 20 Mar 2020 20:14:05 -0400 Received: from mail-pf1-f201.google.com ([209.85.210.201]:53525 "EHLO mail-pf1-f201.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726738AbgCUAOF (ORCPT ); Fri, 20 Mar 2020 20:14:05 -0400 Received: by mail-pf1-f201.google.com with SMTP id i26so5938331pfk.20 for ; Fri, 20 Mar 2020 17:14:04 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:message-id:mime-version:subject:from:to:cc; bh=rKfrdmROUvOZs7vlFYgTzomyfR+aU7XEpJ+VtYWEGxg=; b=c+fFGjuk2m1tfW68i8sSn+ZYRpfp9xXE5oyE3CZ/xCakl9mM6K5LBpq96HlbRHCVdR yFKmU2uQeY49D+kZzagFhU6uW9q01IgMRzNl57PqQAWslxx/t3YEZjnR20CndyEAhrpW 2B+K0eYeNLJElN+RfN1NKz29NRcNHr1tnFGMdD0ts41MHZDY01m6WTfAYbD5SbiAQ3Ku 6QADHsjTERUoIORZEdo0u/nDmIAAyIqNsZnr6MAy1hB2J76j9xzSq6o3r3TqOogieJkA ILd3E4aqV2MtBrJ++TBJ6zSdsYWjHWhvR08qjVcMnI3ovUMm0aU4q7U2nG6tzqjBiNXM 9zBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:message-id:mime-version:subject:from:to:cc; bh=rKfrdmROUvOZs7vlFYgTzomyfR+aU7XEpJ+VtYWEGxg=; b=CiDxpHAGgs/A/U4gYyTT6NbTMCHcvSWWRG0ugvYKBNwoETqsC29iEA4Rwtjqj1QIOe iyr1WVecpZDDi1tByFAU9wAtrUHswXto8mWpl35NXwametlfNnn8tdyVnSU/1l3xg04w LMwOBgHqhLkJuKaH424/0lq7PQTo89mWxhaCqB9Y80KzfllpIXL5dCoa8vwSC3++60vx NMHNdIfEhGBG4rvpAdguf/CpKhBqfqnRbVpGDhWLCPraePMVN4/goZb9twfKqIU6tous 7eFkr5ZL8aW6d/0gdMOGIA1shlWCIDnba97lz7zeLBQk937HVAd7f5OvZdaOtItEbOoy hsXg== X-Gm-Message-State: ANhLgQ2fGENpqWYup0Q5uUpV1LKxvqDMUeITO2F3w68pHmvuU2BkxYax NcyKtXGHCcaS7emV6WhkQE9hmM8h5ATp X-Google-Smtp-Source: ADFU+vuK5hcCKAFaXUA5qKgirZXhfYYf1KjhxNLoVGAhGoEen3x9QbV+hFfJc7/ByBtvbdOrj2PyP1YvVrLv X-Received: by 2002:a17:90b:3656:: with SMTP id nh22mr12172125pjb.38.1584749643969; Fri, 20 Mar 2020 17:14:03 -0700 (PDT) Date: Fri, 20 Mar 2020 17:14:00 -0700 Message-Id: <20200321001400.245121-1-irogers@google.com> Mime-Version: 1.0 X-Mailer: git-send-email 2.25.1.696.g5e7596f4ac-goog Subject: [PATCH] perf test x86: address multiplexing in rdpmc test From: Ian Rogers To: Peter Zijlstra , Ingo Molnar , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Andi Kleen , Kan Liang , linux-kernel@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 Counters may be being used for pinned or other events which inhibit the instruction counter in the test from being scheduled - time_enabled > 0 but time_running == 0. This causes the test to fail with division by 0. Add a sleep loop to ensure that the counter is run before computing the count. Signed-off-by: Ian Rogers --- tools/perf/arch/x86/tests/rdpmc.c | 45 ++++++++++++++++++++++++------- 1 file changed, 35 insertions(+), 10 deletions(-) diff --git a/tools/perf/arch/x86/tests/rdpmc.c b/tools/perf/arch/x86/tests/rdpmc.c index 1ea916656a2d..0b0792ae67f7 100644 --- a/tools/perf/arch/x86/tests/rdpmc.c +++ b/tools/perf/arch/x86/tests/rdpmc.c @@ -34,19 +34,35 @@ static u64 rdtsc(void) return low | ((u64)high) << 32; } -static u64 mmap_read_self(void *addr) +static u64 mmap_read_self(void *addr, bool *error) { struct perf_event_mmap_page *pc = addr; - u32 seq, idx, time_mult = 0, time_shift = 0; + u32 seq, idx, time_mult = 0, time_shift = 0, sleep_count = 0; u64 count, cyc = 0, time_offset = 0, enabled, running, delta; + *error = false; do { - seq = pc->lock; - barrier(); - - enabled = pc->time_enabled; - running = pc->time_running; - + do { + seq = pc->lock; + barrier(); + + enabled = pc->time_enabled; + running = pc->time_running; + + if (running == 0) { + /* + * Event hasn't run, this may be caused by + * multiplexing. + */ + sleep_count++; + if (sleep_count > 60) { + pr_err("Event failed to run. Are higher priority counters being sampled by a different process?\n"); + *error = true; + return 0; + } + sleep(1); + } + } while (running == 0); if (enabled != running) { cyc = rdtsc(); time_mult = pc->time_mult; @@ -131,13 +147,22 @@ static int __test__rdpmc(void) for (n = 0; n < 6; n++) { u64 stamp, now, delta; + bool error; - stamp = mmap_read_self(addr); + stamp = mmap_read_self(addr, &error); + if (error) { + delta_sum = 0; + goto out_close; + } for (i = 0; i < loops; i++) tmp++; - now = mmap_read_self(addr); + now = mmap_read_self(addr, &error); + if (error) { + delta_sum = 0; + goto out_close; + } loops *= 10; delta = now - stamp; -- 2.25.1.696.g5e7596f4ac-goog