From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1KPFVQ-0006nD-Gy for qemu-devel@nongnu.org; Sat, 02 Aug 2008 07:42:40 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1KPFVO-0006m1-QR for qemu-devel@nongnu.org; Sat, 02 Aug 2008 07:42:40 -0400 Received: from [199.232.76.173] (port=35760 helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1KPFVO-0006lq-Jo for qemu-devel@nongnu.org; Sat, 02 Aug 2008 07:42:38 -0400 Received: from mail.codesourcery.com ([65.74.133.4]:59404) by monty-python.gnu.org with esmtps (TLS-1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.60) (envelope-from ) id 1KPFVO-0002ry-4r for qemu-devel@nongnu.org; Sat, 02 Aug 2008 07:42:38 -0400 From: Paul Brook Subject: Re: [Qemu-devel] [RFC][PATCH] Add HPET emulation to qemu (v2) Date: Sat, 2 Aug 2008 12:42:29 +0100 References: <1217675114-17670-1-git-send-email-eak@us.ibm.com> In-Reply-To: <1217675114-17670-1-git-send-email-eak@us.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200808021242.30784.paul@codesourcery.com> Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Beth Kon , Alexander Graf , kvm@vger.kernel.org > I've been playing with CONFIG_NO_HZ and been surprised by the > results. I was trying to reproduce the wakeup every 10ms that > Samuel Thibault mentioned, thinking the HPET would improve it. > But for an idle guest in both cases (with and without HPET), the > number of wakeups per second was relatively low (28). Ultimately > this depends on exactly what the guest is doing Linux can use the existing acpi PM timer a NO_HZ clocksource. Paul