From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from sc8-sf-mx1-b.sourceforge.net ([10.3.1.11] helo=sc8-sf-mx1.sourceforge.net) by sc8-sf-list1.sourceforge.net with esmtp (Exim 4.30) id 1BPqAB-0002v1-M6 for user-mode-linux-devel@lists.sourceforge.net; Mon, 17 May 2004 15:00:47 -0700 Received: from smtp6.wanadoo.fr ([193.252.22.25] helo=mwinf0601.wanadoo.fr) by sc8-sf-mx1.sourceforge.net with esmtp (Exim 4.30) id 1BPqA8-0008KG-AL for user-mode-linux-devel@lists.sourceforge.net; Mon, 17 May 2004 15:00:44 -0700 Subject: Re: [uml-devel] [PATCH] host context switch reduction From: Laurent Vivier In-Reply-To: <02dc01c43c4a$bb7c0490$2000000a@schlepptopp> References: <20040229043549.GA8583@ccure.user-mode-linux.org> <02dc01c43c4a$bb7c0490$2000000a@schlepptopp> Content-Type: multipart/mixed; boundary="=-TS8aHYSZU1j4dAJravpv" Message-Id: <1084831251.1230.4.camel@chartreuse> Mime-Version: 1.0 Sender: user-mode-linux-devel-admin@lists.sourceforge.net Errors-To: user-mode-linux-devel-admin@lists.sourceforge.net List-Unsubscribe: , List-Id: The user-mode Linux development list List-Post: List-Help: List-Subscribe: , List-Archive: Date: Tue, 18 May 2004 00:00:52 +0200 To: roland Cc: user-mode-linux-devel@lists.sourceforge.net --=-TS8aHYSZU1j4dAJravpv Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable X-MIME-Autoconverted: from 8bit to quoted-printable by nerdnet.nl id i4HMABIm007765 Hi, find hereunder the measurements I sent to Jeff. If someone think this patch is really useful for 2.6 I can make the port. Regards, Laurent Please CC: me, as I'm not in the mailing list. Le lun 17/05/2004 =E0 22:08, roland a =E9crit : > hi ! > has this / will this be ported to 2.6 ? > have there been made further performance comparisons ? > regards > roland >=20 >=20 > >Well, we just looked at the context switches. We started 3 UMLs which > >were doing a make world for xfree. Without patches the number of > >context switches per second was around 60k, with the patch it was arou= nd > >40k - so it's noticeable, at least from the cs. > >Sven >=20 > ----- Original Message -----=20 > From: "Jeff Dike" > To: > Sent: Sunday, February 29, 2004 6:35 AM > Subject: [uml-devel] [PATCH] host context switch reduction >=20 >=20 > > The patches below are from Laurent Vivier who didn't make them public= . They > > add a new feature to ptrace on the host which cuts down on the number= of > > context switches needed for a UML system call, plus makes UML use it. > >=20 > > There's some interest in this, so I'm putting it out as-is. I haven'= t played > > with it. > >=20 > > Laurent did some performance testing and found ~40% speedup on a getp= id > > loop, and a 3.5% speedup on a kernel build. > >=20 > > Jeff > >=20 > >=20 --=-TS8aHYSZU1j4dAJravpv Content-Disposition: attachment; filename=measure-getpid.txt Content-Type: text/plain; name=measure-getpid.txt; charset=iso-8859-1 Content-Transfer-Encoding: 7bit #include int main(int argc, char** argv) { int i; int loop = atol(argv[1]); for (i = 0; i < loop; i++) { getpid(); } } NATIF: time ./getpid 10000000 real 0m7.920s user 0m3.990s sys 0m3.940s UML with sysemu real 3m55.052s user 0m5.962s sys 0m46.385s real 3m56.964s user 0m5.846s sys 0m42.635s real 3m54.179s user 0m5.981s sys 0m47.154s UML w/o sysemu real 6m16.956s user 0m5.250s sys 0m58.462s real 6m17.126s user 0m4.846s sys 1m1.731s real 6m16.461s user 0m5.077s sys 0m59.365s --------------------------------------- original UML: time make dep > /dev/null real 4m51.669s user 0m37.462s sys 0m51.846s time make bzImage modules > /dev/null real 13m35.457s user 4m18.885s sys 1m40.481s UML with sysemu: time make dep > /dev/null real 3m52.486s user 0m37.981s sys 0m50.808s time make bzImage modules > /dev/null real 13m5.980s user 4m18.096s sys 1m40.115s --=-TS8aHYSZU1j4dAJravpv-- ------------------------------------------------------- This SF.Net email is sponsored by: SourceForge.net Broadband Sign-up now for SourceForge Broadband and get the fastest 6.0/768 connection for only $19.95/mo for the first 3 months! http://ads.osdn.com/?ad_id=2562&alloc_id=6184&op=click _______________________________________________ User-mode-linux-devel mailing list User-mode-linux-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/user-mode-linux-devel