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=-3.9 required=3.0 tests=BAYES_00,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 C1CC6C4727C for ; Tue, 29 Sep 2020 14:01:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id ECB4E20848 for ; Tue, 29 Sep 2020 14:01:31 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org ECB4E20848 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=crudebyte.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:45044 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1kNGCA-00062i-Kk for qemu-devel@archiver.kernel.org; Tue, 29 Sep 2020 10:01:30 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:45520) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNGAS-0005DN-Ia for qemu-devel@nongnu.org; Tue, 29 Sep 2020 09:59:44 -0400 Received: from kylie.crudebyte.com ([5.189.157.229]:34899) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1kNGAQ-0004A0-Ky for qemu-devel@nongnu.org; Tue, 29 Sep 2020 09:59:44 -0400 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=crudebyte.com; s=kylie; h=Content-Type:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Content-ID:Content-Description; bh=/6jbIRjUAtVZGGk6gEYrACTLQuHei87M+7UfjHxjsLs=; b=nGUS9tRipgxyuo3hpvpRsY8ETE 3hFpqgb614l0CQZNokZh+gDGqtw+VH8g/VPhtZpvLDlBV5QT7knBTPMJsKiLVsvx2He4oXpz9aWyR IgamL7pKWnzD89L0Z+8LQeTGWQNFw/w/aqpZCl0haVCss2uHNDMuujIViEAXMQhE7RFTlSEenmHKr aRC6DIB6pSEkJ9Lylpf/gocxrX/yz7orjg/mgpXDYv0e3m9vMx5KGeLRYN7a1b5B6/Ln5EVEpJUwA kpAg5uyqXnKch6qpHxmx1axAkHSNDiEzhQ1GuYr3w054LpDA1JLEN8g50j7jo9A+BFAY9+6xrJEAD gRvKeqO3uvgWsIg14kv3/5dzXIlz0IKK5hZ3vZhYj0ZIUCtf4j+8Kw2FNvPlT8NkxyesNkSn1slb+ uhMyyzjgvvBnVgiepNPZ4jfipnThTzHUenB16p2mvxwLLjqtMbVMA57lyOrnbNyNvBdMzXMCIZcJ5 1oKOImZocRc4jVN0LGMXkKvpxNpuVhgKJwiKN74E/rcp+tu8CLxPCsb0tO52sT7qR0CnvnV9/5vj3 IsMNRoI1IZ/ycOw+CKs6d7zH5N1gspyDawemnIQBLiLaoo5kLGfxehtdx4EaA6t3XEHeQIXd0M3oi mvkXPErL245YI/9aSCKHNvrQbQY/KO7oIXND+xvfc=; From: Christian Schoenebeck To: qemu-devel@nongnu.org Cc: Vivek Goyal , "Venegas Munoz, Jose Carlos" , "cdupontd@redhat.com" , virtio-fs-list , Stefan Hajnoczi , "Shinde, Archana M" , "Dr. David Alan Gilbert" Subject: Re: virtiofs vs 9p performance(Re: tools/virtiofs: Multi threading seems to hurt performance) Date: Tue, 29 Sep 2020 15:59:34 +0200 Message-ID: <6044656.UxkCsAYsKb@silver> In-Reply-To: <20200929134942.GC220516@redhat.com> References: <20200918213436.GA3520@redhat.com> <2302525.O3mciSdnpG@silver> <20200929134942.GC220516@redhat.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" Received-SPF: pass client-ip=5.189.157.229; envelope-from=qemu_oss@crudebyte.com; helo=kylie.crudebyte.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/09/29 09:28:09 X-ACL-Warn: Detected OS = Linux 3.11 and newer [fuzzy] X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Dienstag, 29. September 2020 15:49:42 CEST Vivek Goyal wrote: > > Depends on what's randomized. If read chunk size is randomized, then yes, > > you would probably see less performance increase compared to a simple > > 'cat foo.dat'. > > We are using "fio" for testing and read chunk size is not being > randomized. chunk size (block size) is fixed at 4K size for these tests. Good to know, thanks! > > If only the read position is randomized, but the read chunk size honors > > iounit, a.k.a. stat's st_blksize (i.e. reading with the most efficient > > block size advertised by 9P), then I would assume still seeing a > > performance increase. > > Yes, we are randomizing read position. But there is no notion of looking > at st_blksize. Its fixed at 4K. (notice option --bs=4k in fio > commandline). Ah ok, then the results make sense. With these block sizes you will indeed suffer a performance issue with 9p, due to several thread hops in Tread handling, which is due to be fixed. Best regards, Christian Schoenebeck