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=-3.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT autolearn=no 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 D7DEAC2D0C2 for ; Mon, 30 Dec 2019 18:15:10 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 9CF93206DB for ; Mon, 30 Dec 2019 18:15:10 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=kernel-dk.20150623.gappssmtp.com header.i=@kernel-dk.20150623.gappssmtp.com header.b="gJvcpD4L" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727403AbfL3SPK (ORCPT ); Mon, 30 Dec 2019 13:15:10 -0500 Received: from mail-yw1-f51.google.com ([209.85.161.51]:37281 "EHLO mail-yw1-f51.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727389AbfL3SPJ (ORCPT ); Mon, 30 Dec 2019 13:15:09 -0500 Received: by mail-yw1-f51.google.com with SMTP id z7so14377185ywd.4 for ; Mon, 30 Dec 2019 10:15:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel-dk.20150623.gappssmtp.com; s=20150623; h=from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=FY9NvcQo+Ay221rC3tOOdmX1FXnP6b/qFNCKzOkIwK8=; b=gJvcpD4LG++K/r1KuvUVlIMKwXcRKulbd/78Q3cUaHZin1EtV7tWgd1fN31wzPcaG0 XKIid+kMfhFqLpbvNebsK8j8G9qxZrc3sWg2DI19tnyi/e8gICBPNxqdnHg/VtbWVxjz IeTD7bmvLmnhjV7NxZe+6tAjffMo7vOLOFT2kmjFkjvmHQb9vSz4RHPSeW2BZ3kPE3sP Clo8Py/B51+ZnWsiSqH/guei/X/1ebmuBx+vUs3GTBtHcLhdyILKDXDdHn6mKJELgvxU WBO6foPiICB90nBWsletkREOzPF9Q8fKphtKE1wWyiNpq/I4/lpvFhP7vg5iJwbB5ctq LeJw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:subject:date:message-id:mime-version :content-transfer-encoding; bh=FY9NvcQo+Ay221rC3tOOdmX1FXnP6b/qFNCKzOkIwK8=; b=XtY+bbqCVYV9MFbxr6ZibR7FV6UEPTdCW9uWEGJ3Ka7r0pj3j3WpHVFsV8CDTDqjtc SunTvcN8+oosu3LCN1AZ9FVK8qCUYBV5ujUB0t+0NPNAwsxQfvlc2KkSQvgJcCOjd1p9 CNo3dGyEjUMRuGcLgE9D/elwpn/n0/oxj9lvrrCql3QHbNuKWqXBu7yPiNZWXO5/a18U mzC7ooAPQDGXWhKqXLmOkjawmokDN+BezmeOhVBp8tHb8ld3ARFnVrNQO7vG3VNQph/6 w5BdEmBxg3qgggzdPE9bKsmSqMk1TQivLSAcqIz+a+cBS9ccdv0FvMS1gAgEIjo6DdS/ OP5w== X-Gm-Message-State: APjAAAW6mtPbXzQQXczG3yPYr9SwC4xnyYWzGXiCefgnBTaO8l4kVdsk p98fIxHOzMXfhspN8QMysPfqF5Vq7lc= X-Google-Smtp-Source: APXvYqw+X0D4dMXL1Ya9MgIMETiQwHOUdMPfCA4pz/iymhafvco1rVcAgIY3vbNXbgTjJLm2KU/Y2g== X-Received: by 2002:a0d:ca14:: with SMTP id m20mr49824332ywd.251.1577729707276; Mon, 30 Dec 2019 10:15:07 -0800 (PST) Received: from x1.localdomain ([8.46.73.113]) by smtp.gmail.com with ESMTPSA id u136sm17879910ywf.101.2019.12.30.10.15.05 for (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 30 Dec 2019 10:15:06 -0800 (PST) From: Jens Axboe To: linux-block@vger.kernel.org Subject: [PATCHSET 0/4] blk-mq: per-ctx tag caching Date: Mon, 30 Dec 2019 11:14:39 -0700 Message-Id: <20191230181442.4460-1-axboe@kernel.dk> X-Mailer: git-send-email 2.24.1 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-block-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org This is something I've been toying with yesterday, and got it cleaned up a bit just now. It's still very much a testing thing, and there's a few debug checks in there and items that need improving. Anyway, the idea here is that we can reduce the cost of getting a tag for a new request, if we don't get them piecemeal. Add a per-ctx tag cache, and grab batches of tags if it's empty. If it's not empty, we can just find a free bit there. /sys/kernel/debug/block////tag_hit holds some stats associated with this, so you can check how it's doing. I've seen nice improvements with this in testing. -- Jens Axboe