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=-10.1 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 302DEC28CBC for ; Wed, 6 May 2020 15:25:11 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0678120B1F for ; Wed, 6 May 2020 15:25:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588778711; bh=L2ExiaFaaJ7NWX2ZeWy30+rPSKc5qvFJX+4HTwcNHAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:List-ID:From; b=J0eXUhFAPZw7ALaN9Ir3Yzh3iw6wcdzmd3flFTfd2DrA+hMFM2JtdCRvUgz2nsQIL T3jVHZN0FXMiz7Fo6059GGjXBn0HS/pW+XodQbqEyhjDWH5LdZeADrlWdA2OKvF3Dd zQwxR4Q+p0OYmDLmoOdWRKSaKSlQH50CHT5DR+UE= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729970AbgEFPZK (ORCPT ); Wed, 6 May 2020 11:25:10 -0400 Received: from mail.kernel.org ([198.145.29.99]:44374 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729455AbgEFPZG (ORCPT ); Wed, 6 May 2020 11:25:06 -0400 Received: from quaco.ghostprotocols.net (unknown [179.97.37.151]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 26057215A4; Wed, 6 May 2020 15:25:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1588778705; bh=L2ExiaFaaJ7NWX2ZeWy30+rPSKc5qvFJX+4HTwcNHAk=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sBwkKPsqo2ezpXRLVukNGNcdKjcTLfUX9AuVGhhZocvNQ3Bp1POS5hdesfGBN5cSx S+nQBr2ZYBunUnemKuWJFiTJWUSEBFCL7MHriR4EQfbCefLeRExNa6EPtgDgyksIgl 47U1c9pgcb77sp3V9zOUrVyfwDtSog64kjCL5o5o= From: Arnaldo Carvalho de Melo To: Ingo Molnar , Thomas Gleixner Cc: Jiri Olsa , Namhyung Kim , Clark Williams , linux-kernel@vger.kernel.org, linux-perf-users@vger.kernel.org, Konstantin Khlebnikov , Andi Kleen , Dmitry Monakhov , Kan Liang , Peter Zijlstra , Arnaldo Carvalho de Melo Subject: [PATCH 38/91] perf tools: Simplify checking if SMT is active. Date: Wed, 6 May 2020 12:21:41 -0300 Message-Id: <20200506152234.21977-39-acme@kernel.org> X-Mailer: git-send-email 2.21.1 In-Reply-To: <20200506152234.21977-1-acme@kernel.org> References: <20200506152234.21977-1-acme@kernel.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Konstantin Khlebnikov SMT now could be disabled via "/sys/devices/system/cpu/smt/control". Status is shown in "/sys/devices/system/cpu/smt/active" simply as "0" / "1". If this knob isn't here then fallback to checking topology as before. Signed-off-by: Konstantin Khlebnikov Cc: Andi Kleen Cc: Dmitry Monakhov Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/158817741394.748034.9273604089138009552.stgit@buzz Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/smt.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/perf/util/smt.c b/tools/perf/util/smt.c index 8481842e9edb..20bacd5972ad 100644 --- a/tools/perf/util/smt.c +++ b/tools/perf/util/smt.c @@ -15,6 +15,9 @@ int smt_on(void) if (cached) return cached_result; + if (sysfs__read_int("devices/system/cpu/smt/active", &cached_result) > 0) + goto done; + ncpu = sysconf(_SC_NPROCESSORS_CONF); for (cpu = 0; cpu < ncpu; cpu++) { unsigned long long siblings; @@ -42,6 +45,7 @@ int smt_on(void) } if (!cached) { cached_result = 0; +done: cached = true; } return cached_result; -- 2.21.1