From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:50403) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yq03k-00005G-Fv for qemu-devel@nongnu.org; Wed, 06 May 2015 10:12:25 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1Yq03g-0005Cw-D9 for qemu-devel@nongnu.org; Wed, 06 May 2015 10:12:24 -0400 Received: from mx1.redhat.com ([209.132.183.28]:53834) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1Yq03g-0005Ck-8s for qemu-devel@nongnu.org; Wed, 06 May 2015 10:12:20 -0400 Message-ID: <554A2142.7090006@redhat.com> Date: Wed, 06 May 2015 10:12:18 -0400 From: John Snow MIME-Version: 1.0 References: <1430864578-22072-1-git-send-email-jsnow@redhat.com> <1430864578-22072-5-git-send-email-jsnow@redhat.com> <87pp6eusrz.fsf@blackfin.pond.sub.org> In-Reply-To: <87pp6eusrz.fsf@blackfin.pond.sub.org> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH v3 4/5] qtest: precompute hex nibs List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Markus Armbruster Cc: pbonzini@redhat.com, qemu-devel@nongnu.org, afaerber@suse.de On 05/06/2015 02:25 AM, Markus Armbruster wrote: > John Snow writes: > >> Instead of letting printf and friends do this for us >> one byte at a time, fill a buffer ourselves and then >> send the entire buffer in one go. >> >> This gives a moderate speed improvement over the old >> method. > > Out of curiosity: how much of the improvement is due to doing our own > buffering instead of printf()'s (assuming the stream is buffered), and > how much is due to doing our own hex formatting instead of printf()'s? > Out of ignorance: How would I measure?