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=-0.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS 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 1E7C2C38A24 for ; Thu, 7 May 2020 08:10:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id EE4C220753 for ; Thu, 7 May 2020 08:10:28 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=chromium.org header.i=@chromium.org header.b="HHTWe/aw" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725953AbgEGIK2 (ORCPT ); Thu, 7 May 2020 04:10:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46228 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1725848AbgEGIK2 (ORCPT ); Thu, 7 May 2020 04:10:28 -0400 Received: from mail-yb1-xb43.google.com (mail-yb1-xb43.google.com [IPv6:2607:f8b0:4864:20::b43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CEA9CC061A10 for ; Thu, 7 May 2020 01:10:27 -0700 (PDT) Received: by mail-yb1-xb43.google.com with SMTP id a8so2484637ybs.3 for ; Thu, 07 May 2020 01:10:27 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=chromium.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=H8Cu6HxLa77jfVaZq3CgdIap4XuJaTdN0YbC0ZBDI6M=; b=HHTWe/aw3WAO0yhwglTuWvnXtft80GNiSghWxIrZ8pm3zAl6YWCPBliDTGEgkmScPn GRXl7egcPPz7vscL5sn1MgH+ZlgS20+7153v5mN3c8Sv5/SOt/jdmqkdfKiaabkOmQmY JkkTTl0/M/DXPC/fmTCboG4vGxTAISZ/GlWe0= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=H8Cu6HxLa77jfVaZq3CgdIap4XuJaTdN0YbC0ZBDI6M=; b=Mjy4DmpyXi9iIag0KDQHIEOJRP64Hy87gLAbLL2D4zT65CrrX6O+7yzE5jfGOPPH2w yUiZ5m2rVUMjvf3PNaXjGPIpbRpw/mTPTcZxNqrNvOKFa5YnI+2KIasEEMu3ibwOb+Rp LqDatyONTyk75JUctGooWFpau7qHvPT07shE7faV/IOTKrLEzGu8PW/L/WZGwwf/8Hbg V+dIxg59SeI9zePILKLCmTsz8y/j0zwujtHDg5az3X3tsoS9/uywzBBzmzk7z3j46LLA A8wYHsF0TtnBDjBKMEibkWd57+CGHTX9Bu19bHTgLWIIaX9garMwB6exx8l9tc0U3y2P 266A== X-Gm-Message-State: AGi0PuZFloRrASaJ34SdD6BP26cSz4/MpkPSwM/Mx2td44Srz4BioW/p s6qwY017d4DKaolYV5ZZOD8UUzGYfBsoGWlS0s5wow== X-Google-Smtp-Source: APiQypJCQTdVxRjuBFFsXs0gT1xdcUYEcYrD4ZAzch0VY2vs2mJSoKpfKRsJM7D1YGqA0M/kjdDVOVS3+4q+aOuqDx0= X-Received: by 2002:a25:448a:: with SMTP id r132mr22208820yba.277.1588839026841; Thu, 07 May 2020 01:10:26 -0700 (PDT) MIME-Version: 1.0 References: <20200424062540.23679-1-chirantan@chromium.org> <20200424062540.23679-2-chirantan@chromium.org> <20200427151934.GB1042399@stefanha-x1.localdomain> <20200501154752.GA222606@stefanha-x1.localdomain> In-Reply-To: <20200501154752.GA222606@stefanha-x1.localdomain> From: Chirantan Ekbote Date: Thu, 7 May 2020 17:10:15 +0900 Message-ID: Subject: Re: [PATCH 2/2] fuse: virtiofs: Add basic multiqueue support To: Stefan Hajnoczi Cc: Miklos Szeredi , Vivek Goyal , Linux FS Devel , virtio-fs-list , Dylan Reid , Suleiman Souhlal , slp@redhat.com Content-Type: text/plain; charset="UTF-8" Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org On Sat, May 2, 2020 at 12:48 AM Stefan Hajnoczi wrote: > > On Fri, May 01, 2020 at 04:14:38PM +0900, Chirantan Ekbote wrote: > > On Tue, Apr 28, 2020 at 12:20 AM Stefan Hajnoczi wrote: > > > Instead of modifying the guest driver, please implement request > > > parallelism in your device implementation. > > > > Yes, we have tried this already [1][2]. As I mentioned above, having > > additional threads in the server actually made performance worse. My > > theory is that when the device only has 2 cpus, having additional > > threads on the host that need cpu time ends up taking time away from > > the guest vcpu. We're now looking at switching to io_uring so that we > > can submit multiple requests from a single thread. > > The host has 2 CPUs? How many vCPUs does the guest have? What is the > physical storage device? What is the host file system? The host has 2 cpus. The guest has 1 vcpu. The physical storage device is an internal ssd. The file system is ext4 with directory encryption. > > io_uring's vocabulary is expanding. It can now do openat2(2), close(2), > statx(2), but not mkdir(2), unlink(2), rename(2), etc. > > I guess there are two options: > 1. Fall back to threads for FUSE operations that cannot yet be done via > io_uring. > 2. Process FUSE operations that cannot be done via io_uring > synchronously. > I'm hoping that using io_uring for just the reads and writes should give us a big enough improvement that we can do the rest of the operations synchronously. Chirantan