Date: Sun, 11 Aug 2013 15:40:09 -0600 From: Scott Long <scott4long@yahoo.com> To: Alexander Motin <mav@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org, Scott Long <scottl@FreeBSD.org> Subject: Re: svn commit: r253460 - head/sys/dev/mps Message-ID: <E28B06A7-D09C-4CFB-ABCA-CD9FC43E89E6@yahoo.com> In-Reply-To: <52077D0D.8090607@FreeBSD.org> References: <201307190012.r6J0Cg1r027645@svn.freebsd.org> <52077D0D.8090607@FreeBSD.org>
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Thanks, I'll look into it. Scott On Aug 11, 2013, at 6:01 AM, Alexander Motin <mav@FreeBSD.org> wrote: > On 19.07.2013 03:12, Scott Long wrote: >> Author: scottl >> Date: Fri Jul 19 00:12:41 2013 >> New Revision: 253460 >> URL: http://svnweb.freebsd.org/changeset/base/253460 >> >> Log: >> Overhaul error, information, and debug logging. >> >> Obtained from: Netflix >> MFC after: 3 days >> >> Modified: >> head/sys/dev/mps/mps.c >> head/sys/dev/mps/mps_mapping.c >> head/sys/dev/mps/mps_pci.c >> head/sys/dev/mps/mps_sas.c >> head/sys/dev/mps/mps_sas_lsi.c >> head/sys/dev/mps/mps_table.c >> head/sys/dev/mps/mps_user.c >> head/sys/dev/mps/mpsvar.h > > This change created significant CPU overhead under high I/O rate (350K IOPS) because several functions inside mpssas_log_command() are now writing into the buffer that is just discarded after that. The following simple patch seems fixes the situation for me: > > Index: mps_sas.c > =================================================================== > --- mps_sas.c (revision 254181) > +++ mps_sas.c (working copy) > @@ -304,7 +304,7 @@ mpssas_log_command(struct mps_command *cm, u_int l > char str[192]; > char path_str[64]; > > - if (cm == NULL) > + if (cm == NULL || (cm->cm_sc->mps_debug & level) == 0) > return; > > sbuf_new(&sb, str, sizeof(str), 0); > > > -- > Alexander Motin
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