From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mailman by lists.gnu.org with tmda-scanned (Exim 4.43) id 1IMqUk-0008S4-81 for qemu-devel@nongnu.org; Sun, 19 Aug 2007 15:31:30 -0400 Received: from exim by lists.gnu.org with spam-scanned (Exim 4.43) id 1IMqUi-0008PY-GG for qemu-devel@nongnu.org; Sun, 19 Aug 2007 15:31:29 -0400 Received: from [199.232.76.173] (helo=monty-python.gnu.org) by lists.gnu.org with esmtp (Exim 4.43) id 1IMqUi-0008PD-4c for qemu-devel@nongnu.org; Sun, 19 Aug 2007 15:31:28 -0400 Received: from il.qumranet.com ([82.166.9.18]) by monty-python.gnu.org with esmtp (Exim 4.60) (envelope-from ) id 1IMqUh-0006ty-Lb for qemu-devel@nongnu.org; Sun, 19 Aug 2007 15:31:27 -0400 Message-ID: <46C89A8E.7040609@qumranet.com> Date: Sun, 19 Aug 2007 22:31:26 +0300 From: Avi Kivity MIME-Version: 1.0 References: <20070817231149.544849769@gmail.com> <1187450256.13580.1.camel@squirrel> <64F9B87B6B770947A9F8391472E032160D4645F0@ehost011-8.exch011.intermedia.net> <20070818220252.GA19526@dreamland.darkstar.lan> <68676e00708190952g7d4751c2g87a6ff71dd278f71@mail.gmail.com> In-Reply-To: <68676e00708190952g7d4751c2g87a6ff71dd278f71@mail.gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: [Qemu-devel] Re: [kvm-devel] [PATCH 0/4] Rework alarm timer infrastrucure - take2 Reply-To: qemu-devel@nongnu.org List-Id: qemu-devel.nongnu.org List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Luca Cc: kvm-devel@lists.sf.net, qemu-devel@nongnu.org Luca wrote: > On 8/19/07, Luca Tettamanti wrote: > >> +static uint64_t qemu_next_deadline(void) { >> + uint64_t nearest_delta_us = ULLONG_MAX; >> + uint64_t vmdelta_us; >> > > Hum, I introduced a bug here... those vars should be signed. > > On the overhead introduced: how do you measure it? > > Run a 100Hz guest, measure cpu usage using something accurate like cyclesoak, with and without dynticks, with and without kvm. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic.