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=-9.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 D8A06C35669 for ; Mon, 24 Feb 2020 03:31:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A7FC72067D for ; Mon, 24 Feb 2020 03:31:03 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="M3wDz0iS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727213AbgBXDbC (ORCPT ); Sun, 23 Feb 2020 22:31:02 -0500 Received: from mail-pl1-f194.google.com ([209.85.214.194]:34058 "EHLO mail-pl1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727166AbgBXDbC (ORCPT ); Sun, 23 Feb 2020 22:31:02 -0500 Received: by mail-pl1-f194.google.com with SMTP id j7so3476211plt.1 for ; Sun, 23 Feb 2020 19:31:01 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id; bh=Yejd20Vwzkjy8wctsJA53OKjv5gxUU+XuqGntcv4+CU=; b=M3wDz0iS7qqef+rCSuMgCtuEz2fPfB0i2PQQPSDRrzLM71oR9VagSgkgIIH+/fmtyz nAYbPEAUaPwa9yyiFLjrIpWiSBWdYHu/m3TZp+4X0zsnhc9mTl2kKrWWYSa+rQQ80JGa fpnMuz2cYu8X/YaJeCZfLCxS+WM1p+5qYQWdUun8bDZP4JkFcH/8P0kH/zYLUTwWt/4Q aVbZd81IuRb2N0kJYgAH9EDE3gGkbKembOjzSZJnTuQcNFlm/exeO+Js8Ja6Fbwv4gCp reNy+jVi2UL3rY3pSzx4MKRU+TN2dxWEC2SVuJdif0mzpGS+M6otQ3oTIbAqqPMAUISj 4ZkA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id; bh=Yejd20Vwzkjy8wctsJA53OKjv5gxUU+XuqGntcv4+CU=; b=TK+7l+8kZJIiGDc9gMKy7+3cCiBsNLNioik2db+VYrJ9/zX9u8zYi/7v62MB+l0diE YaKMv6NW7Odk3Fmz6DPudWVVLyl80YSJPzn0d2payuVWTczObA9yXVLzFa9Ka7TYXxLa O2Vw1XrJq9UWNazNloRFv4untV2kiTr+GOT0LfS0p2QEMgqGhyjd2gcWohWdKsAk85Dg Z+LIJfxxe6JRNXr5bkqyWiftWEmPMjBjpvXgDQ21LCDN51ozC8nOV3a3WQf3owG612ha 3ZhVO9EHmdMxZhWoe+ArPesnp6IfkRyQCPoerRQJIRH/zsu2345rC38CRyZlC+jtAeKx OPvA== X-Gm-Message-State: APjAAAV1njAtK8Csxb9P+dyRNJZQBYfxUhYLqoi/xEu5QLu5ugAu4211 BQ2643dEkOGeYQhFtg4fl0GBNJBPsZA= X-Google-Smtp-Source: APXvYqz09B0TtrBg/YMiwim1nibuNRPTxkXazNNiOqJVMtuRX4OI6AZ22CCf2Ygv2e3wRNdpB+zIAw== X-Received: by 2002:a17:90a:7f93:: with SMTP id m19mr17247993pjl.92.1582515061569; Sun, 23 Feb 2020 19:31:01 -0800 (PST) Received: from localhost ([43.224.245.179]) by smtp.gmail.com with ESMTPSA id a17sm10375623pfo.146.2020.02.23.19.31.00 (version=TLS1_2 cipher=AES128-SHA bits=128/128); Sun, 23 Feb 2020 19:31:01 -0800 (PST) From: qiwuchen55@gmail.com To: mingo@redhat.com, peterz@infradead.org, juri.lelli@redhat.com, vincent.guittot@linaro.org, dietmar.eggemann@arm.com, rostedt@goodmis.org, bsegall@google.com, mgorman@suse.de Cc: linux-kernel@vger.kernel.org, chenqiwu Subject: [PATCH] sched/pelt: use shift operation instead of division operation Date: Mon, 24 Feb 2020 11:30:55 +0800 Message-Id: <1582515055-14515-1-git-send-email-qiwuchen55@gmail.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: chenqiwu Use shift operation to calculate the periods instead of division, since shift operation is more efficient than division operation. Signed-off-by: chenqiwu --- kernel/sched/pelt.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/sched/pelt.c b/kernel/sched/pelt.c index bd006b7..ac79f8e 100644 --- a/kernel/sched/pelt.c +++ b/kernel/sched/pelt.c @@ -114,7 +114,7 @@ static u32 __accumulate_pelt_segments(u64 periods, u32 d1, u32 d3) u64 periods; delta += sa->period_contrib; - periods = delta / 1024; /* A period is 1024us (~1ms) */ + periods = delta >> 10; /* A period is 1024us (~1ms) */ /* * Step 1: decay old *_sum if we crossed period boundaries. -- 1.9.1