Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753423Ab0ATNhu (ORCPT ); Wed, 20 Jan 2010 08:37:50 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752146Ab0ATNhr (ORCPT ); Wed, 20 Jan 2010 08:37:47 -0500 Received: from mx1.redhat.com ([209.132.183.28]:56107 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751591Ab0ATNhq (ORCPT ); Wed, 20 Jan 2010 08:37:46 -0500 Date: Wed, 20 Jan 2010 07:37:34 -0600 From: Clark Williams To: Thomas Gleixner Cc: RT , LKML , Carsten Emde , John Kacur Subject: Re: RFC: NUMA modifications to cyclictest Message-ID: <20100120073734.4be7a52b@torg> In-Reply-To: References: <20100119171439.24726f2e@torg> Organization: Red Hat, Inc Mime-Version: 1.0 Content-Type: multipart/signed; micalg=PGP-SHA1; boundary="Sig_/dSWNDpu1MzBAg+Lj9jzN+/2"; protocol="application/pgp-signature" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2702 Lines: 64 --Sig_/dSWNDpu1MzBAg+Lj9jzN+/2 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable On Wed, 20 Jan 2010 07:51:41 +0100 (CET) Thomas Gleixner wrote: > On Tue, 19 Jan 2010, Clark Williams wrote: > > RT-ers, > >=20 > > Lately we've been struggling with some performance issues on high-core > > count (>16 cores) NUMA machines with the RT kernel. During the course > > of troubleshooting this issue, we tried using the 'numactl' program to > > constrain our measurement testing tool (rteval) to a particular memory > > node, rather than letting everything float. Doing so showed marked > > improvement in both max latency and jitter. While this doesn't solve > > our performance problems I thought it might make sense to have a --numa > > mode for cylictest that compliments the --smp mode just added.=20 > >=20 > > The big difference here is that when using --numa, each measurement > > thread (one per cpu) has it's stack allocated from the memory node > > associated with it's cpu. Also, the major data structures for each > > thread (parameter block, statistics block and histogram) are allocated > > from the appropriate node. This is done with calls into libnuma, > > which means this will add a dependency on libnuma.=20 >=20 > That might cause some trouble for embedded folks. :( Yeah, that's why I send the RFC, wanted to see who would hate me for it :). Carsten already told me off-list that one of his build machines didn't have numa.h, so I'm going to have to rearrange the build a bit. As much as I hate to say it, I think the best option is to use autoconf to detect if libnuma is available on the build platform and to take appropriate steps if it's not.=20 The other idea I toyed with was dynamic loading of libnuma so there's not an install dependency for the libnuma package with the rt-tests package. I only use five functions from libnuma, so that's not too bad a set of function pointers to manage. Hmmm, that probably won't work very well, since I'll still have to include numa.h. Sigh... Clark --Sig_/dSWNDpu1MzBAg+Lj9jzN+/2 Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.13 (GNU/Linux) iEYEARECAAYFAktXByIACgkQHyuj/+TTEp0OtwCfZa2g3qej2MA8RCO/R16NJulx /p4Anied3kZJF+nXaLVqgbXQZd+CRA7Y =M8XX -----END PGP SIGNATURE----- --Sig_/dSWNDpu1MzBAg+Lj9jzN+/2-- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/