From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([208.118.235.92]:35023) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TNifq-00034e-Lz for qemu-devel@nongnu.org; Mon, 15 Oct 2012 07:17:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1TNifp-0001Pu-KI for qemu-devel@nongnu.org; Mon, 15 Oct 2012 07:17:30 -0400 Received: from mx1.redhat.com ([209.132.183.28]:18504) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1TNifp-0001Pp-CB for qemu-devel@nongnu.org; Mon, 15 Oct 2012 07:17:29 -0400 Received: from int-mx10.intmail.prod.int.phx2.redhat.com (int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q9FBHSQN014600 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Mon, 15 Oct 2012 07:17:28 -0400 Message-ID: <507BF0C6.9010300@redhat.com> Date: Mon, 15 Oct 2012 13:17:26 +0200 From: Gerd Hoffmann MIME-Version: 1.0 References: <1350297511-25437-1-git-send-email-hdegoede@redhat.com> <1350297511-25437-7-git-send-email-hdegoede@redhat.com> In-Reply-To: <1350297511-25437-7-git-send-email-hdegoede@redhat.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 06/22] ehci: Speed up the timer of raising int from the async schedule List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Hans de Goede Cc: qemu-devel@nongnu.org On 10/15/12 12:38, Hans de Goede wrote: > Often the guest will queue up new packets in response to a packet, in the > async schedule with its IOC flag set, completing. By speeding up the > frame-timer, we notice these new packets earlier. This increases the > speed (MB/s) of a Linux guest reading from a USB mass storage device by a > factor of 1.15 on top of the "Improve latency of interrupt delivery" > speed-ups, both with and without input pipelining enabled. Why not just set async_stepdown to 0? cheers, Gerd