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{ "id": 2196350, "url": "http://patchwork.ozlabs.org/api/covers/2196350/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/cover/20260213143225.161043-1-axboe@kernel.dk/", "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": "<20260213143225.161043-1-axboe@kernel.dk>", "list_archive_url": null, "date": "2026-02-13T14:26:35", "name": "[PATCHSET,0/2] io_uring fixes", "submitter": { "id": 4515, "url": "http://patchwork.ozlabs.org/api/people/4515/?format=api", "name": "Jens Axboe", "email": "axboe@kernel.dk" }, "mbox": "http://patchwork.ozlabs.org/project/qemu-devel/cover/20260213143225.161043-1-axboe@kernel.dk/mbox/", "series": [ { "id": 492105, "url": "http://patchwork.ozlabs.org/api/series/492105/?format=api", "web_url": "http://patchwork.ozlabs.org/project/qemu-devel/list/?series=492105", "date": "2026-02-13T14:26:37", "name": "io_uring fixes", "version": 1, "mbox": "http://patchwork.ozlabs.org/series/492105/mbox/" } ], "comments": "http://patchwork.ozlabs.org/api/covers/2196350/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=kernel-dk.20230601.gappssmtp.com\n header.i=@kernel-dk.20230601.gappssmtp.com header.a=rsa-sha256\n header.s=20230601 header.b=Zf3X4Dp1;\n\tdkim-atps=neutral", "legolas.ozlabs.org;\n spf=pass (sender SPF authorized) smtp.mailfrom=nongnu.org\n (client-ip=209.51.188.17; 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helo=mail-ot1-x32e.google.com", "X-Spam_score_int": "-18", "X-Spam_score": "-1.9", "X-Spam_bar": "-", "X-Spam_report": "(-1.9 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1,\n DKIM_VALID=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001,\n SPF_PASS=-0.001 autolearn=unavailable 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": "Hi,\n\nPatch 1 here is the real meat of this, patch 2 is just a slight\nimprovement. For patch 1, it can literally yield a 50-80x improvement\non the io_uring side for idle systems, where ppoll() ends up sleeping\nfor 500 msec while there's IO to submit! I noticed this running the\nio_uring regression tests in a vm, where I use a variety of block\ndevices for some of the tests. They would often randomly time out on\nAHCI devices, while running them on a virtio-blk or nvme device would\nfinish in one second or so. I then wrote a reproducer to try and grok\nthis and had claude dive into this, which helped me better grasp the\nvarious event loops.\n\nPlease take a look and tell me what you think. Some variant of patch 1\nshould definitely be considered, but let me know if this is the right\napproach. I can easily test anything.\n\nAlso note - this seems to trigger more easily or consistently on\naarch64, which is where I run most of my local/immediate testing.\n\n util/fdmon-io_uring.c | 22 +++++++++++++++++++++-\n 1 file changed, 21 insertions(+), 1 deletion(-)" }