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[80.230.47.107]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-49996100184sm215978925e9.1.2026.08.17.12.55.18 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 17 Aug 2026 12:55:19 -0700 (PDT) Date: Mon, 17 Aug 2026 15:55:16 -0400 From: "Michael S. Tsirkin" To: Mirza Ishan Beg Cc: virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Jason Wang , Xuan Zhuo , Eugenio =?iso-8859-1?Q?P=E9rez?= Subject: Re: [PATCH] virtio_pci_modern: replace msleep(1) with usleep_range(1000, 2000) Message-ID: <20260817155125-mutt-send-email-mst@kernel.org> References: <20260816173806-mutt-send-email-mst@kernel.org> <20260817170331.219615-2-seedandsyntax@gmail.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260817170331.219615-2-seedandsyntax@gmail.com> On Mon, Aug 17, 2026 at 10:33:31PM +0530, Mirza Ishan Beg wrote: > 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 I don't think we care anyway. We probably just want fsleep?