From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([209.51.188.92]:53982) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hLsE5-0002rq-PV for qemu-devel@nongnu.org; Wed, 01 May 2019 12:37:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hLsE2-0003RQ-NX for qemu-devel@nongnu.org; Wed, 01 May 2019 12:36:57 -0400 Received: from mail-io1-xd42.google.com ([2607:f8b0:4864:20::d42]:33620) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hLsE2-0003Nx-GM for qemu-devel@nongnu.org; Wed, 01 May 2019 12:36:54 -0400 Received: by mail-io1-xd42.google.com with SMTP id u12so15311912iop.0 for ; Wed, 01 May 2019 09:36:54 -0700 (PDT) Date: Wed, 1 May 2019 12:36:50 -0400 From: Stefan Hajnoczi Message-ID: <20190501163650.GF21155@stefanha-x1.localdomain> References: <60340EAF-4C85-4798-9999-34F1A37E2086@oracle.com> <898ef1d4-bfa2-9952-8ceb-f1282b85e29c@oracle.com> <20190416092042.GB32709@stefanha-x1.localdomain> <8E5AF770-69ED-4D44-8A25-B51344996D9E@oracle.com> <3F7E854A-3C1D-4204-8C35-893FC0614796@oracle.com> <20190423120453.GF32465@stefanha-x1.localdomain> <44520476-d6a8-2e3f-1602-388e2e1e874e@redhat.com> <20190429134048.GH7587@stefanha-x1.localdomain> <1A278B43-AA26-43B4-B6C2-17231E780BBE@oracle.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Zi0sgQQBxRFxMTsj" Content-Disposition: inline In-Reply-To: <1A278B43-AA26-43B4-B6C2-17231E780BBE@oracle.com> Subject: Re: [Qemu-devel] Following up questions related to QEMU and I/O Thread List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Wei Li Cc: Stefan Hajnoczi , Paolo Bonzini , Dongli Zhang , qemu-devel@nongnu.org --Zi0sgQQBxRFxMTsj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Apr 29, 2019 at 10:56:31AM -0700, Wei Li wrote: > Does this mean the performance could be improved via adding Batch I/O submission support in Guest driver side which will be able to reduce the number of virtqueue kicks? Yes, I think so. It's not obvious to me how a Linux SCSI driver is supposed to implement batching though. The .queuecommand API doesn't seem to include information relevant to batching. Stefan --Zi0sgQQBxRFxMTsj Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAlzJywoACgkQnKSrs4Gr c8ibRQgApviIvzBkdGSYDCfxjvmfv9kjionlS8Vj63GB5PtcEok9fvOoaQlXHIni syrKPmZxcBVTLKmie1H5QBecbOU6FFr/wfaIQd/VIe9E2/hDjEsJKYSfQyr2vqEh lpKb9yNfiguVWQThCruqNkwRxh62sQL9w/okJjXt+igyjNlQmonxhRMLok/AOu6Z 36td6F3oCfkEPA3apaAEbtv9mvt3ztKJ7C9tuD4U9/vSgsKNUircByDBFaxYX2GO 3zFaFo5RP10Z6aRdtOlwRdRe3Kl9DfVidVTKDf2moYHiwyvBC7nlyfMMxT810Two ii7c1hAReVJBmJaGtwmLUwRntZZnXA== =GFKD -----END PGP SIGNATURE----- --Zi0sgQQBxRFxMTsj-- 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=-2.0 required=3.0 tests=DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 7DBD3C43219 for ; Wed, 1 May 2019 16:38:04 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 4372F2064A for ; Wed, 1 May 2019 16:38:04 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="C7f7+ejl" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4372F2064A Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([127.0.0.1]:36433 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hLsF9-0003HU-IB for qemu-devel@archiver.kernel.org; Wed, 01 May 2019 12:38:03 -0400 Received: from eggs.gnu.org ([209.51.188.92]:53982) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1hLsE5-0002rq-PV for qemu-devel@nongnu.org; Wed, 01 May 2019 12:37:00 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1hLsE2-0003RQ-NX for qemu-devel@nongnu.org; Wed, 01 May 2019 12:36:57 -0400 Received: from mail-io1-xd42.google.com ([2607:f8b0:4864:20::d42]:33620) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1hLsE2-0003Nx-GM for qemu-devel@nongnu.org; Wed, 01 May 2019 12:36:54 -0400 Received: by mail-io1-xd42.google.com with SMTP id u12so15311912iop.0 for ; Wed, 01 May 2019 09:36:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to:user-agent; bh=pIbW7GzOBrDJL8zGiWX9TbqAbhyUF4FlYUJ8pozloh0=; b=C7f7+ejlEnCMUH7wEw1BDcH/bDmwELWn31M8VZKcyoLKYXO6rmxMs73G2LWBQFLl+o Jub6loq+CVxFXRDuSKdlQ5CVVTzs+qkBooYjPukdSBKqmPNsTUl4pJRgxdMEDe7BJyg/ 3nP3JY4QSBIwjRCf9iKdbwIPJlWfN/0UZRT3DpRY/BJ+BTDVQ9ogjdSj2EX5C88mwCSB 6/fprn6zHGo9RAZ0QE422PjpVGJ7Et/GBvHqSjUMcjUuDTCPB5t9EG5MRH9gzPBvlELa gLwwin1tnJn6sRQYn60HKTOEuS2vUpYYld6eVM5kS5PTGJr3BPz9Bn61j2ruiKaUaV2W Oopg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to:user-agent; bh=pIbW7GzOBrDJL8zGiWX9TbqAbhyUF4FlYUJ8pozloh0=; b=V9qGvOsB78/vsaRgAdYvTvG5kDN/VRlITqR+EPBC7cQovLCFfZ8j4syZEbETtlp1MF DqL+dDwJT3JZ12NQTL+0Rr//8UOA9wIeH44MW+RTR30e/qHq9BFOjm+SD+KheptHMQ1d 4fMs3l+Qx+S+4OblnJyBF2kViBv2LFGEtcmUljd2U7I3pg5eANj/iKVraAxpbcTKEImF F7rMhoi+xB5K/Xp8pFxD7jvNFoPP3usyDZnDAEHc4qQWs04NRRvtevUbMipcbeS7CH5J Apch8SN4mkWqEgeRc7uS4ULsIjHdInNcooyLux/vreUHgS5Rw9xKMM4J22jU/4UuZ0Il iKkA== X-Gm-Message-State: APjAAAUe/BCyjugosmKIuhe//LU4TGRhdxh/hjvNn18NhzvfMJQfWClZ 5wS+GzSx33cZyhXk7cxAwTg= X-Google-Smtp-Source: APXvYqzGriMDXZaaA5sZBT5Fy/lwzTRVDFbJvdDYYtIsvN6j8s54CZGOt+qGDxaY45Vb7IJwaYHcMQ== X-Received: by 2002:a6b:b714:: with SMTP id h20mr17518766iof.68.1556728613461; Wed, 01 May 2019 09:36:53 -0700 (PDT) Received: from localhost (CPE64777d5479c3-CM64777d5479c0.cpe.net.cable.rogers.com. [99.228.64.175]) by smtp.gmail.com with ESMTPSA id b72sm3241036itc.30.2019.05.01.09.36.51 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 01 May 2019 09:36:52 -0700 (PDT) Date: Wed, 1 May 2019 12:36:50 -0400 From: Stefan Hajnoczi To: Wei Li Message-ID: <20190501163650.GF21155@stefanha-x1.localdomain> References: <60340EAF-4C85-4798-9999-34F1A37E2086@oracle.com> <898ef1d4-bfa2-9952-8ceb-f1282b85e29c@oracle.com> <20190416092042.GB32709@stefanha-x1.localdomain> <8E5AF770-69ED-4D44-8A25-B51344996D9E@oracle.com> <3F7E854A-3C1D-4204-8C35-893FC0614796@oracle.com> <20190423120453.GF32465@stefanha-x1.localdomain> <44520476-d6a8-2e3f-1602-388e2e1e874e@redhat.com> <20190429134048.GH7587@stefanha-x1.localdomain> <1A278B43-AA26-43B4-B6C2-17231E780BBE@oracle.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha256; protocol="application/pgp-signature"; boundary="Zi0sgQQBxRFxMTsj" Content-Disposition: inline In-Reply-To: <1A278B43-AA26-43B4-B6C2-17231E780BBE@oracle.com> User-Agent: Mutt/1.11.4 (2019-03-13) X-detected-operating-system: by eggs.gnu.org: Genre and OS details not recognized. X-Received-From: 2607:f8b0:4864:20::d42 Subject: Re: [Qemu-devel] Following up questions related to QEMU and I/O Thread X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Paolo Bonzini , qemu-devel@nongnu.org, Stefan Hajnoczi , Dongli Zhang Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Message-ID: <20190501163650.mx7UKaKJHiYAUez2dsq-qCjH39XketFgU5DBTAvckQo@z> --Zi0sgQQBxRFxMTsj Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Mon, Apr 29, 2019 at 10:56:31AM -0700, Wei Li wrote: > Does this mean the performance could be improved via adding Batch I/O submission support in Guest driver side which will be able to reduce the number of virtqueue kicks? Yes, I think so. It's not obvious to me how a Linux SCSI driver is supposed to implement batching though. The .queuecommand API doesn't seem to include information relevant to batching. Stefan --Zi0sgQQBxRFxMTsj Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAEBCAAdFiEEhpWov9P5fNqsNXdanKSrs4Grc8gFAlzJywoACgkQnKSrs4Gr c8ibRQgApviIvzBkdGSYDCfxjvmfv9kjionlS8Vj63GB5PtcEok9fvOoaQlXHIni syrKPmZxcBVTLKmie1H5QBecbOU6FFr/wfaIQd/VIe9E2/hDjEsJKYSfQyr2vqEh lpKb9yNfiguVWQThCruqNkwRxh62sQL9w/okJjXt+igyjNlQmonxhRMLok/AOu6Z 36td6F3oCfkEPA3apaAEbtv9mvt3ztKJ7C9tuD4U9/vSgsKNUircByDBFaxYX2GO 3zFaFo5RP10Z6aRdtOlwRdRe3Kl9DfVidVTKDf2moYHiwyvBC7nlyfMMxT810Two ii7c1hAReVJBmJaGtwmLUwRntZZnXA== =GFKD -----END PGP SIGNATURE----- --Zi0sgQQBxRFxMTsj--