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Tsirkin" Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jason Wang , Xuan Zhuo , =?UTF-8?q?Eugenio=20P=C3=A9rez?= , Mirza Ishan Beg Subject: Re: [PATCH] virtio_pci_modern: replace msleep(1) with usleep_range(1000, 2000) Date: Mon, 17 Aug 2026 22:33:31 +0530 Message-ID: <20260817170331.219615-2-seedandsyntax@gmail.com> X-Mailer: git-send-email 2.47.3 In-Reply-To: <20260816173806-mutt-send-email-mst@kernel.org> References: <20260816173806-mutt-send-email-mst@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit On Sun, Aug 16, 2026 at 05:38:06PM -0400, Michael S. Tsirkin wrote: > why do we care? Hi Michael, The motivation originally came from a checkpatch.pl warning, but looking directly at Documentation/timers/timers-howto.rst, there is a practical penalty here. The documentation explicitly notes for the 1-20ms range: "msleep(1~20) may not do what the caller intends, and will often sleep longer (~20 ms actual sleep for any value given in the 1~20ms range)." In these queue reset loops, using msleep(1) means each iteration may be extended to 10-20ms depending on HZ and timer slack. The document recommends using usleep_range() to avoid this overhead and provide the intended precision. Let me know if you'd like this explanation folded into a v2 commit message. -- Mirza