From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:51438) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WIK2T-0008C4-Dy for qemu-devel@nongnu.org; Tue, 25 Feb 2014 10:35:27 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1WIK2O-0001mp-N1 for qemu-devel@nongnu.org; Tue, 25 Feb 2014 10:35:21 -0500 Received: from mail-qg0-x22d.google.com ([2607:f8b0:400d:c04::22d]:63574) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1WIK2O-0001mh-FD for qemu-devel@nongnu.org; Tue, 25 Feb 2014 10:35:16 -0500 Received: by mail-qg0-f45.google.com with SMTP id j5so1483059qga.4 for ; Tue, 25 Feb 2014 07:35:16 -0800 (PST) Sender: Richard Henderson Message-ID: <530CB82C.9040509@twiddle.net> Date: Tue, 25 Feb 2014 07:35:08 -0800 From: Richard Henderson MIME-Version: 1.0 References: <1393339545-22111-1-git-send-email-peter.maydell@linaro.org> In-Reply-To: <1393339545-22111-1-git-send-email-peter.maydell@linaro.org> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH] target-arm: Implement WFE as a yield operation List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Peter Maydell , qemu-devel@nongnu.org Cc: Rob Herring , patches@linaro.org On 02/25/2014 06:45 AM, Peter Maydell wrote: > Implement WFE to yield our timeslice to the next CPU. > This avoids slowdowns in multicore configurations caused > by one core busy-waiting on a spinlock which can't possibly > be unlocked until the other core has an opportunity to run. > This speeds up my test case A15 dual-core boot by a factor > of three (though it is still four or five times slower than > a single-core boot). > > Signed-off-by: Peter Maydell Reviewed-by: Richard Henderson r~