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GET /api/patches/2218179/?format=api
{ "id": 2218179, "url": "http://patchwork.ozlabs.org/api/patches/2218179/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260331150352.256332-6-kwolf@redhat.com/", "project": { "id": 14, "url": "http://patchwork.ozlabs.org/api/projects/14/?format=api", "name": "QEMU Development", "link_name": "qemu-devel", "list_id": "qemu-devel.nongnu.org", "list_email": "qemu-devel@nongnu.org", "web_url": "", "scm_url": "", "webscm_url": "", "list_archive_url": "", "list_archive_url_format": "", "commit_url_format": "" }, "msgid": "<20260331150352.256332-6-kwolf@redhat.com>", "list_archive_url": null, "date": "2026-03-31T15:03:51", "name": "[PULL,5/6] vhost-user-blk-server: fix opt_io_size=1 causing severe Windows I/O degradation", "commit_ref": null, "pull_url": null, "state": "new", "archived": false, "hash": "530e6e030056b645d12e31a001f8b5afb76d3c25", "submitter": { "id": 2714, "url": "http://patchwork.ozlabs.org/api/people/2714/?format=api", "name": "Kevin Wolf", "email": "kwolf@redhat.com" }, "delegate": null, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/patch/20260331150352.256332-6-kwolf@redhat.com/mbox/", "series": [ { "id": 498214, "url": "http://patchwork.ozlabs.org/api/series/498214/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=498214", "date": "2026-03-31T15:03:47", "name": "[PULL,1/6] ide: Fix potential assertion failure on VM stop for PIO read error", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/498214/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/patches/2218179/comments/", "check": "pending", "checks": "http://patchwork.ozlabs.org/api/patches/2218179/checks/", "tags": {}, "related": [], "headers": { "Return-Path": "<qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org>", "X-Original-To": "incoming@patchwork.ozlabs.org", "Delivered-To": "patchwork-incoming@legolas.ozlabs.org", "Authentication-Results": [ "legolas.ozlabs.org;\n\tdkim=pass (1024-bit key;\n unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256\n header.s=mimecast20190719 header.b=dEDlsmUo;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; helo=lists.gnu.org;\n envelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n receiver=patchwork.ozlabs.org)" ], "Received": [ "from lists.gnu.org (lists.gnu.org [209.51.188.17])\n\t(using TLSv1.2 with cipher ECDHE-ECDSA-AES256-GCM-SHA384 (256/256 bits))\n\t(No client certificate requested)\n\tby legolas.ozlabs.org (Postfix) with ESMTPS id 4flWdl01zPz1yGT\n\tfor <incoming@patchwork.ozlabs.org>; Wed, 01 Apr 2026 02:05:46 +1100 (AEDT)", "from localhost ([::1] helo=lists1p.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.90_1)\n\t(envelope-from <qemu-devel-bounces@nongnu.org>)\n\tid 1w7adZ-0003Iv-7p; Tue, 31 Mar 2026 11:04:13 -0400", "from eggs.gnu.org ([2001:470:142:3::10])\n by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <kwolf@redhat.com>) id 1w7adX-0003Fe-Cf\n for qemu-devel@nongnu.org; Tue, 31 Mar 2026 11:04:11 -0400", "from us-smtp-delivery-124.mimecast.com ([170.10.133.124])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256)\n (Exim 4.90_1) (envelope-from <kwolf@redhat.com>) id 1w7adW-0002Z9-2T\n for qemu-devel@nongnu.org; Tue, 31 Mar 2026 11:04:11 -0400", "from mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com\n (ec2-35-165-154-97.us-west-2.compute.amazonaws.com [35.165.154.97]) by\n relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3,\n cipher=TLS_AES_256_GCM_SHA384) id us-mta-528-rmiI-oJDNdKshv0HcyWhTA-1; Tue,\n 31 Mar 2026 11:04:08 -0400", "from mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com\n (mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.17])\n (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)\n key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest\n SHA256)\n (No client certificate requested)\n by mx-prod-mc-06.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS\n id 102B61800624; Tue, 31 Mar 2026 15:04:07 +0000 (UTC)", "from merkur.redhat.com (unknown [10.44.50.38])\n by mx-prod-int-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTP\n id AA86919540C4; Tue, 31 Mar 2026 15:04:05 +0000 (UTC)" ], "DKIM-Signature": "v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;\n s=mimecast20190719; t=1774969449;\n h=from:from:reply-to:subject:subject:date:date:message-id:message-id:\n to:to:cc:cc:mime-version:mime-version:\n content-transfer-encoding:content-transfer-encoding:\n in-reply-to:in-reply-to:references:references;\n bh=F7l7nol1SzwFYWkkAmybwaQvn6WrYq0DfYyxo8Bu/rc=;\n b=dEDlsmUo35G3VkdAmbUlHit+B4qFc73i4kl0COgIssRZ1VSDTmB7u9KujxciW8emNhL3UC\n KOkbxSvM/AMaQ9igfijRFzlaWdK7R1zBHa0KlhlDTWW1aaqCYceXCmlxwmoFysX2Zdp89X\n mu+Xit253CoJc8t0IizakX/MWFVH0Qo=", "X-MC-Unique": "rmiI-oJDNdKshv0HcyWhTA-1", "X-Mimecast-MFC-AGG-ID": "rmiI-oJDNdKshv0HcyWhTA_1774969447", "From": "Kevin Wolf <kwolf@redhat.com>", "To": "qemu-block@nongnu.org", "Cc": "kwolf@redhat.com,\n\tqemu-devel@nongnu.org,\n\tpeter.maydell@linaro.org", "Subject": "[PULL 5/6] vhost-user-blk-server: fix opt_io_size=1 causing severe\n Windows I/O degradation", "Date": "Tue, 31 Mar 2026 17:03:51 +0200", "Message-ID": "<20260331150352.256332-6-kwolf@redhat.com>", "In-Reply-To": "<20260331150352.256332-1-kwolf@redhat.com>", "References": "<20260331150352.256332-1-kwolf@redhat.com>", "MIME-Version": "1.0", "Content-Transfer-Encoding": "8bit", "X-Scanned-By": "MIMEDefang 3.0 on 10.30.177.17", "Received-SPF": "pass client-ip=170.10.133.124; envelope-from=kwolf@redhat.com;\n helo=us-smtp-delivery-124.mimecast.com", "X-Spam_score_int": "-6", "X-Spam_score": "-0.7", "X-Spam_bar": "/", "X-Spam_report": "(-0.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.54,\n DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1,\n RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H2=-0.01,\n RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=1, RCVD_IN_VALIDITY_RPBL_BLOCKED=1,\n SPF_HELO_PASS=-0.001, SPF_PASS=-0.001 autolearn=no autolearn_force=no", "X-Spam_action": "no action", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.29", "Precedence": "list", "List-Id": "qemu development <qemu-devel.nongnu.org>", "List-Unsubscribe": "<https://lists.nongnu.org/mailman/options/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>", "List-Archive": "<https://lists.nongnu.org/archive/html/qemu-devel>", "List-Post": "<mailto:qemu-devel@nongnu.org>", "List-Help": "<mailto:qemu-devel-request@nongnu.org?subject=help>", "List-Subscribe": "<https://lists.nongnu.org/mailman/listinfo/qemu-devel>,\n <mailto:qemu-devel-request@nongnu.org?subject=subscribe>", "Errors-To": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org", "Sender": "qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org" }, "content": "From: Max Makarov <maxpain177@gmail.com>\n\nThe QSD vhost-user-blk export sets opt_io_size=1 and min_io_size=1 in\nthe virtio config. These values are reported to the guest through the\nVPD Block Limits page as OptimalTransferLength=1 block (512 bytes)\nand OptimalTransferLengthGranularity=1 block.\n\nWindows respects these hints and splits all I/O into ~512-byte\nrequests, causing ~100x sequential throughput degradation (150 MB/s\ninstead of 15+ GB/s). Linux is unaffected as its block layer ignores\nthese values.\n\nSet both to 0 which means \"not reported\" per the SCSI Block Limits\nVPD spec, allowing Windows to use its own optimal I/O size defaults.\n\nSigned-off-by: Max Makarov <maxpain@linux.com>\nMessage-ID: <20260330193451.76037-1-maxpain@linux.com>\nReviewed-by: Kevin Wolf <kwolf@redhat.com>\nSigned-off-by: Kevin Wolf <kwolf@redhat.com>\n---\n block/export/vhost-user-blk-server.c | 4 ++--\n 1 file changed, 2 insertions(+), 2 deletions(-)", "diff": "diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c\nindex e89422bb85a..67912a3e170 100644\n--- a/block/export/vhost-user-blk-server.c\n+++ b/block/export/vhost-user-blk-server.c\n@@ -242,8 +242,8 @@ vu_blk_initialize_config(BlockDriverState *bs,\n config->blk_size = cpu_to_le32(blk_size);\n config->size_max = cpu_to_le32(0);\n config->seg_max = cpu_to_le32(128 - 2);\n- config->min_io_size = cpu_to_le16(1);\n- config->opt_io_size = cpu_to_le32(1);\n+ config->min_io_size = cpu_to_le16(0);\n+ config->opt_io_size = cpu_to_le32(0);\n config->num_queues = cpu_to_le16(num_queues);\n config->max_discard_sectors =\n cpu_to_le32(VIRTIO_BLK_MAX_DISCARD_SECTORS);\n", "prefixes": [ "PULL", "5/6" ] }