From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:42413) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1fTS7k-0006ES-5q for qemu-devel@nongnu.org; Thu, 14 Jun 2018 09:17:14 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1fTS7f-0002PY-28 for qemu-devel@nongnu.org; Thu, 14 Jun 2018 09:17:11 -0400 Date: Thu, 14 Jun 2018 15:16:52 +0200 From: Kevin Wolf Message-ID: <20180614131652.GF8564@localhost.localdomain> References: <20180608192027.284601-1-vsementsov@virtuozzo.com> <20180608192027.284601-4-vsementsov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20180608192027.284601-4-vsementsov@virtuozzo.com> Subject: Re: [Qemu-devel] [PATCH 3/3] qcow2: add compress threads List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Vladimir Sementsov-Ogievskiy Cc: qemu-devel@nongnu.org, qemu-block@nongnu.org, mreitz@redhat.com, stefanha@gmail.com, pl@kamp.de, den@openvz.org Am 08.06.2018 um 21:20 hat Vladimir Sementsov-Ogievskiy geschrieben: > Do data compression in separate threads. This significantly improve > performance for qemu-img convert with -W (allow async writes) and -c > (compressed) options. > > Signed-off-by: Vladimir Sementsov-Ogievskiy Looks correct to me, but why do we introduce a separate MAX_COMPRESS_THREADS? Can't we simply leave the maximum number of threads to the thread poll? I see that you chose a much smaller number here (4 vs. 64), but is there actually a good reason for this? Kevin