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=-6.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 4A79FC432C3 for ; Fri, 15 Nov 2019 06:47:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F52920723 for ; Fri, 15 Nov 2019 06:47:56 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=linaro.org header.i=@linaro.org header.b="F7E4azdR" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726986AbfKOGrs (ORCPT ); Fri, 15 Nov 2019 01:47:48 -0500 Received: from mail-wm1-f65.google.com ([209.85.128.65]:37413 "EHLO mail-wm1-f65.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725848AbfKOGrr (ORCPT ); Fri, 15 Nov 2019 01:47:47 -0500 Received: by mail-wm1-f65.google.com with SMTP id b17so9086053wmj.2 for ; Thu, 14 Nov 2019 22:47:46 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=h6eijrK8cUxC8CXdJIBcySFLn2s6ouwc2eAMAO7Yyes=; b=F7E4azdR9jYdXe9IJM6V6g32ncVAFgLfs5WJQff5l0YFLEhwd00g0L91wRPaLhN8NA 2RG4IL/h2dLth8xKeqwfuRWasWCOhr2Wq5N4rTq+RqWGo7Z2xTSx5/iRfK9jINGsgp5N V3irs7/8A/mQb1GvLKWE7NZT5ZPtL2T3dgfh6N+fm5wdw116AgoslDwixkp5Vtd+9DJv 0QMpS77XlFxg6yxa/bfrp6iK518+NROIXwI62+w0s+hVu8rcW4cVQKTpx2svKLpXiXuE rdJ2PmHAao9o4wuuu9c+JzVvUnvwL8TiKxLGelI7TDtChfH7U1poW11maB2nzD1biEGQ 8vLw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:subject:from:in-reply-to:date:cc :content-transfer-encoding:message-id:references:to; bh=h6eijrK8cUxC8CXdJIBcySFLn2s6ouwc2eAMAO7Yyes=; b=e+8A7ZauV8WGdVCG9msuXQsxSTOxJfJjYDAYdsuHKC9rX0Je9jc4M5/A0B3TqpoY5U GL89yv7fE8IT56/5apBsUr/NZr9rph1lnjtOfPsshtVErfzve7UsUF67KNR2X2ws/NWu OH09H7XFFidOdcBaYJ8hZcKP3cWrckagffyQYakDqRj24f8hqUkmkBzYvP2jOFeGbCOX lxK8914C5wVUzRmHSob0WtNH0G7VoJUVkREXw9y+RDmF9MHRf1b84XIKdoTSsH/vlTnA p1xX4bQZ06U1whBfKgg9rGlbZLfCv207LQO2LoY+lBSsYoMShPT/YEA7JrramBZ+dOE7 4F5A== X-Gm-Message-State: APjAAAWi9cbZiUh/nSX/lRUmG7ys0HOWdqWlNaM+5T6XNZIn4Ldg/od3 X62C3Z7mBTEWFRqglcOFz3zH1w== X-Google-Smtp-Source: APXvYqwGXJtQkCBTsweQQRswiTBThypUGLrtgVwXGSWzzCLlpWA9L/kHnXqlVPEQ8MPJE01QlngFZg== X-Received: by 2002:a05:600c:296:: with SMTP id 22mr12909062wmk.155.1573800465347; Thu, 14 Nov 2019 22:47:45 -0800 (PST) Received: from [192.168.0.100] (84-33-69-45.dyn.eolo.it. [84.33.69.45]) by smtp.gmail.com with ESMTPSA id f14sm9916446wrv.17.2019.11.14.22.47.44 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 14 Nov 2019 22:47:44 -0800 (PST) Content-Type: text/plain; charset=us-ascii Mime-Version: 1.0 (Mac OS X Mail 12.4 \(3445.104.8\)) Subject: Re: [PATCH] block,bfq: Skip tracing hooks if possible From: Paolo Valente In-Reply-To: <20191101131110.18356-1-dmonakhov@gmail.com> Date: Fri, 15 Nov 2019 07:47:43 +0100 Cc: linux-kernel , axboe@kernel.dk Content-Transfer-Encoding: quoted-printable Message-Id: References: <20191101131110.18356-1-dmonakhov@gmail.com> To: Dmitry Monakhov X-Mailer: Apple Mail (2.3445.104.8) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > Il giorno 1 nov 2019, alle ore 14:11, Dmitry Monakhov = ha scritto: >=20 > In most cases blk_tracing is not active, but bfq_log_bfqq macro > generate pid_str unconditionally, which result in significant = overhead. >=20 > ## Test > modprobe null_blk > echo bfq > /sys/block/nullb0/queue/scheduler > fio --name=3Dt --ioengine=3Dlibaio --direct=3D1 --filename=3D/dev/nullb0= \ > --runtime=3D30 --time_based=3D1 --rw=3Dwrite --iodepth=3D128 --bs=3D4k= >=20 > # Results > | | baseline | w/ patch | gain | > | iops | 113.19K | 126.42K | +11% | >=20 Thank you very much for this simple yet effective improvement. Acked-by: Paolo Valente > Signed-off-by: Dmitry Monakhov > --- > block/bfq-iosched.h | 4 ++++ > 1 file changed, 4 insertions(+) >=20 > diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h > index 5d1a519..b320fe9 100644 > --- a/block/bfq-iosched.h > +++ b/block/bfq-iosched.h > @@ -1062,6 +1062,8 @@ struct bfq_group *bfqq_group(struct bfq_queue = *bfqq); >=20 > #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { = \ > char pid_str[MAX_PID_STR_LENGTH]; \ > + if (likely(!blk_trace_note_message_enabled((bfqd)->queue))) = \ > + break; = \ > bfq_pid_to_str((bfqq)->pid, pid_str, MAX_PID_STR_LENGTH); = \ > blk_add_cgroup_trace_msg((bfqd)->queue, = \ > bfqg_to_blkg(bfqq_group(bfqq))->blkcg, = \ > @@ -1078,6 +1080,8 @@ struct bfq_group *bfqq_group(struct bfq_queue = *bfqq); >=20 > #define bfq_log_bfqq(bfqd, bfqq, fmt, args...) do { \ > char pid_str[MAX_PID_STR_LENGTH]; \ > + if (likely(!blk_trace_note_message_enabled((bfqd)->queue))) = \ > + break; = \ > bfq_pid_to_str((bfqq)->pid, pid_str, MAX_PID_STR_LENGTH); = \ > blk_add_trace_msg((bfqd)->queue, "bfq%s%c " fmt, pid_str, = \ > bfq_bfqq_sync((bfqq)) ? 'S' : 'A', = \ > --=20 > 2.7.4 >=20