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{ "id": 2194216, "url": "http://patchwork.ozlabs.org/api/covers/2194216/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/cover/20260207120901.17222-1-hibriansong@gmail.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": "<20260207120901.17222-1-hibriansong@gmail.com>", "list_archive_url": null, "date": "2026-02-07T12:08:54", "name": "[v4,0/7] add fuse-over-io_uring support", "submitter": { "id": 90672, "url": "http://patchwork.ozlabs.org/api/people/90672/?format=api", "name": "Brian Song", "email": "hibriansong@gmail.com" }, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/cover/20260207120901.17222-1-hibriansong@gmail.com/mbox/", "series": [ { "id": 491376, "url": "http://patchwork.ozlabs.org/api/series/491376/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=491376", "date": "2026-02-07T12:08:56", "name": "add fuse-over-io_uring support", "version": 4, "mbox": "http://patchwork.ozlabs.org/series/491376/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2194216/comments/", "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 (2048-bit key;\n unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256\n header.s=20230601 header.b=FL+cj1Y0;\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 4f7Vxk2PRjz1xvh\n\tfor <incoming@patchwork.ozlabs.org>; Sat, 07 Feb 2026 23:43:36 +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 1voh8Q-00077X-3A; Sat, 07 Feb 2026 07:09:58 -0500", "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 <hibriansong@gmail.com>)\n id 1voh7x-00073K-Rr\n for qemu-devel@nongnu.org; Sat, 07 Feb 2026 07:09:34 -0500", "from mail-pg1-x530.google.com ([2607:f8b0:4864:20::530])\n by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128)\n (Exim 4.90_1) (envelope-from <hibriansong@gmail.com>)\n id 1voh7r-0002qH-Mb\n for qemu-devel@nongnu.org; Sat, 07 Feb 2026 07:09:27 -0500", "by mail-pg1-x530.google.com with SMTP id\n 41be03b00d2f7-c6dd5b01e14so510409a12.0\n for <qemu-devel@nongnu.org>; Sat, 07 Feb 2026 04:09:19 -0800 (PST)", "from brian.. 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helo=mail-pg1-x530.google.com", "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,\n DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, FREEMAIL_FROM=0.001,\n RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=ham autolearn_force=no", "X-Spam_action": "no action", "X-BeenThere": "qemu-devel@nongnu.org", "X-Mailman-Version": "2.1.29", "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": "Hello everyone,\n\nThis patch series introduces native io_uring support for FUSE storage\nexport to overcome the scalability limits of the /dev/fuse interface.\nBy utilizing shared memory ring buffers and per-core queues, this\nfeature drastically reduces context switch overhead and lock contention.\nThis allows FUSE export daemons to achieve much higher throughput and\nlower latency by minimizing the userspace-kernel switch penalty.\n\nMore details on Fuse-over-io_uring:\nhttps://docs.kernel.org/filesystems/fuse/fuse-io-uring.html\n\n\nChanges in this version:\n\n- Reorganized patch structure.\n- Unified naming of Uring data structures (e.g. FuseRing -> FuseUring)\n- Refactored FUSE_IN/OUT_OP_STRUCT_LEGACY\n- Code cleanup and logic simplification:\n\t- Used the io_uring flag to indicate the intention to enable\n\t Fuse-over-io_uring.\n\t- Used uring_started to track the active state.\n\t- Removed unnecessary #ifdef CONFIG_LINUX_IO_URING guards.\n- Moved fuse_fd closing to BH in uring mode to prevent data races.\n- Updated tests: now using mount to verify if the test image mount is\n fully gone.\n\nMore detail in the v3 cover letter:\nhttps://lists.nongnu.org/archive/html/qemu-block/2025-08/msg00325.html\n\nV2 cover letter:\nhttps://lists.nongnu.org/archive/html/qemu-block/2025-08/msg00140.html\n\nV1 cover letter:\nhttps://lists.nongnu.org/archive/html/qemu-block/2025-07/msg00280.html\n\nWe used fio to test a 1GB file under both legacy FUSE and\nFUSE-over-io_uring modes. The experiments were conducted with the\nfollowing iodepth and numjobs configurations: 1-1, 64-1, 1-4, and 64-4,\nwith 70% read and 30% write mix. This resulted in a total of 8 test\ncases, measuring both latency and throughput.\n\nPerformance Results:\n\n[Bandwidth (MiB/s)]\n| Config (Job/QD) | Read (Leg -> Uring) | Write (Leg -> Uring)|\n|------------------|---------------------|---------------------|\n| 1 Job, QD=1 | 72.2 -> 104 | 30.9 -> 44.7 |\n| 1 Job, QD=64 | 114 -> 181 | 48.8 -> 77.7 |\n| 4 Jobs, QD=1 | 109 -> 159 | 47.0 -> 68.5 |\n| 4 Jobs, QD=64 | 106 -> 160 | 45.7 -> 68.9 |\n\n[Latency (usec)]\n| Config (Job/QD) | Read (Leg -> Uring) | Write (Leg -> Uring)|\n|------------------|---------------------|---------------------|\n| 1 Job, QD=1 | 37.0 -> 23.7 | 36.9 -> 29.5 |\n| 1 Job, QD=64 | 1537 -> 964 | 1535 -> 967 |\n| 4 Jobs, QD=1 | 96.6 -> 66.4 | 114.2 -> 71.9 |\n| 4 Jobs, QD=64 | 6560 -> 4234 | 6600 -> 4280 |\n\nBrian Song (7):\n [Patch v4 1/7] aio-posix: enable 128-byte SQEs\n [Patch v4 2/7] fuse: io_uring mode init\n [Patch v4 3/7] fuse: uring support for write ops\n [Patch v4 4/7] fuse: refactor FUSE request handler\n [Patch v4 5/6] fuse: safe termination for io_uring\n [Patch v4 6/7] fuse: add 'io-uring' option\n [Patch v4 7/7] fuse: add io_uring test support\n\n block/export/fuse.c | 958 +++++++++++++++++++++++----\n docs/tools/qemu-storage-daemon.rst | 7 +-\n qapi/block-export.json | 5 +-\n storage-daemon/qemu-storage-daemon.c | 1 +\n tests/qemu-iotests/check | 2 +\n tests/qemu-iotests/common.rc | 47 +-\n util/fdmon-io_uring.c | 7 +-\n 7 files changed, 879 insertions(+), 148 deletions(-)\n\n--\n2.43.0" }