From patchwork Tue Mar 12 08:59:31 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Paolo Valente X-Patchwork-Id: 10848771 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 6249614DE for ; Tue, 12 Mar 2019 09:00:54 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 4DF9929597 for ; Tue, 12 Mar 2019 09:00:54 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 4B724295AF; Tue, 12 Mar 2019 09:00:54 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.0 required=2.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id BED3029592 for ; Tue, 12 Mar 2019 09:00:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727774AbfCLJAj (ORCPT ); Tue, 12 Mar 2019 05:00:39 -0400 Received: from mail-wm1-f67.google.com ([209.85.128.67]:53723 "EHLO mail-wm1-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727688AbfCLJAK (ORCPT ); Tue, 12 Mar 2019 05:00:10 -0400 Received: by mail-wm1-f67.google.com with SMTP id e74so1707198wmg.3 for ; Tue, 12 Mar 2019 02:00:09 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=3yl3XU7a49GA8s9ZssN4iqwWKfxKo62fpyxLFCHTfdM=; b=l21Jl1yZjVVBrUCvymJJxze0ysYHTiw8TwtK9e3AcziIbTngV9WXO4AnA9uaSTgijV D9MiZAR73lQWdDxKHhfzUeEpliUC5D0O9sZw0nt2rKKp8HrBo8chqhzCVM9OsrR/kIlL P0pyx7lS+4XtIDzMH0kO89P5l+IhAEwDth3GMsu2NSFiVT8BxqLESpvxWTN5Q0iPqB/W ImhpUq7ArZI6iObjZu8dHr/cRWWH4zFWQkkJxcYC5RrkB53h8LJ16qt/3BnkWHZlz59o +TmHndTPD2q4e/yulwkvL/dGT7lE7gfxkW0XWYl0rGKQu4IjNcr6yfThWciXGbglUCA8 QJ4w== 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:in-reply-to :references:mime-version:content-transfer-encoding; bh=3yl3XU7a49GA8s9ZssN4iqwWKfxKo62fpyxLFCHTfdM=; b=fB1UduCC/VjFc4QRxQjvzemsafTSqluf+n/SZ74QhD6CEycqDbBABZ/G/DH1zidI0F RkGXV3yF7SSx5zXHLFVb+RaBTkb6evxDMdoJntqp/GUumxEDB4Vas8/kZIbZIguCFfCE BfPL0/SJs2CkW1nCO6FTet4vRjkM6HdADBd7/q/dhWEXLkF7WeW6QJh909Ju6ng87xNe bbrlsmYpJlCHzDG1zhEL3AlyvurixfdIM1R5LwYO3H154FoJZgvZ/CqIlPnKxMxEoMzK 6MKTISI+eO9Jly5P6JQ9yuY3cuE6E0E4OMyBKwZoUm/cD/nB0sZ8JsMAQwkS5LbPyMN5 24EQ== X-Gm-Message-State: APjAAAXAGgr2OGOoCYkvGYTWp8YbS6NAZdA0khnYJ4Fv3Eic+3cvpRab ZdSUfjNfAopx/DckeAbaji01IQ== X-Google-Smtp-Source: APXvYqzQ7IHQ9WwuM0Q9tw7gv7qFqwjCUs6TELpsRlFlDakqOvH8fKgNzrzIbsrEQi8VLBL974Z4rw== X-Received: by 2002:a1c:9694:: with SMTP id y142mr1501451wmd.98.1552381209127; Tue, 12 Mar 2019 02:00:09 -0700 (PDT) Received: from localhost.localdomain ([84.33.65.66]) by smtp.gmail.com with ESMTPSA id y20sm3953043wmi.34.2019.03.12.02.00.07 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 12 Mar 2019 02:00:08 -0700 (PDT) From: Paolo Valente To: Jens Axboe Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org, ulf.hansson@linaro.org, linus.walleij@linaro.org, broonie@kernel.org, bfq-iosched@googlegroups.com, oleksandr@natalenko.name, fra.fra.800@gmail.com, alessio.masola@gmail.com, holger@applied-asynchrony.com, Paolo Valente Subject: [PATCH BUGFIX IMPROVEMENT V3 5/9] block, bfq: do not tag totally seeky queues as soft rt Date: Tue, 12 Mar 2019 09:59:31 +0100 Message-Id: <20190312085935.11340-6-paolo.valente@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20190312085935.11340-1-paolo.valente@linaro.org> References: <20190312085935.11340-1-paolo.valente@linaro.org> MIME-Version: 1.0 Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Sync random I/O is likely to be confused with soft real-time I/O, because it is characterized by limited throughput and apparently isochronous arrival pattern. To avoid false positives, this commits prevents bfq_queues containing only random (seeky) I/O from being tagged as soft real-time. Tested-by: Holger Hoffstätte Tested-by: Oleksandr Natalenko Signed-off-by: Paolo Valente --- block/bfq-iosched.c | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/block/bfq-iosched.c b/block/bfq-iosched.c index b96be3764b8a..d34b80e5c47d 100644 --- a/block/bfq-iosched.c +++ b/block/bfq-iosched.c @@ -242,6 +242,14 @@ static struct kmem_cache *bfq_pool; blk_rq_sectors(rq) < BFQQ_SECT_THR_NONROT)) #define BFQQ_CLOSE_THR (sector_t)(8 * 1024) #define BFQQ_SEEKY(bfqq) (hweight32(bfqq->seek_history) > 19) +/* + * Sync random I/O is likely to be confused with soft real-time I/O, + * because it is characterized by limited throughput and apparently + * isochronous arrival pattern. To avoid false positives, queues + * containing only random (seeky) I/O are prevented from being tagged + * as soft real-time. + */ +#define BFQQ_TOTALLY_SEEKY(bfqq) (bfqq->seek_history & -1) /* Min number of samples required to perform peak-rate update */ #define BFQ_RATE_MIN_SAMPLES 32 @@ -1622,6 +1630,7 @@ static void bfq_bfqq_handle_idle_busy_switch(struct bfq_data *bfqd, */ in_burst = bfq_bfqq_in_large_burst(bfqq); soft_rt = bfqd->bfq_wr_max_softrt_rate > 0 && + !BFQQ_TOTALLY_SEEKY(bfqq) && !in_burst && time_is_before_jiffies(bfqq->soft_rt_next_start) && bfqq->dispatched == 0; @@ -4816,6 +4825,11 @@ bfq_update_io_seektime(struct bfq_data *bfqd, struct bfq_queue *bfqq, { bfqq->seek_history <<= 1; bfqq->seek_history |= BFQ_RQ_SEEKY(bfqd, bfqq->last_request_pos, rq); + + if (bfqq->wr_coeff > 1 && + bfqq->wr_cur_max_time == bfqd->bfq_wr_rt_max_time && + BFQQ_TOTALLY_SEEKY(bfqq)) + bfq_bfqq_end_wr(bfqq); } static void bfq_update_has_short_ttime(struct bfq_data *bfqd,