From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bob Peterson Date: Wed, 22 Apr 2015 13:00:09 -0400 (EDT) Subject: [Cluster-devel] [GFS2 PATCH] GFS2: Average in only non-zero round-trip times for congestion stats In-Reply-To: <1202489161.4769650.1429721928815.JavaMail.zimbra@redhat.com> Message-ID: <1549641874.4770984.1429722009576.JavaMail.zimbra@redhat.com> List-Id: To: cluster-devel.redhat.com MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Hi, This patch changes function gfs2_rgrp_congested so that it only factors in non-zero values into its average round trip time. If the round-trip time is zero for a particular cpu, that cpu has obviously never dealt with bouncing the resource group in question, so factoring in a zero value will only skew the numbers. It also fixes a compile error on some arches related to division. Regards, Bob Peterson Signed-off-by: Bob Peterson --- diff --git a/fs/gfs2/rgrp.c b/fs/gfs2/rgrp.c index f39eedc..cb27065 100644 --- a/fs/gfs2/rgrp.c +++ b/fs/gfs2/rgrp.c @@ -1854,15 +1854,19 @@ static bool gfs2_rgrp_congested(const struct gfs2_rgrpd *rgd, int loops) s64 srttb_diff; s64 sqr_diff; s64 var; - int cpu; + int cpu, nonzero = 0; preempt_disable(); for_each_present_cpu(cpu) { st = &per_cpu_ptr(sdp->sd_lkstats, cpu)->lkstats[LM_TYPE_RGRP]; - a_srttb += st->stats[GFS2_LKS_SRTTB]; + if (st->stats[GFS2_LKS_SRTTB]) { + a_srttb += st->stats[GFS2_LKS_SRTTB]; + nonzero++; + } } st = &this_cpu_ptr(sdp->sd_lkstats)->lkstats[LM_TYPE_RGRP]; - a_srttb /= num_present_cpus(); + if (nonzero) + do_div(a_srttb, nonzero); r_dcount = st->stats[GFS2_LKS_DCOUNT]; var = st->stats[GFS2_LKS_SRTTVARB] + gl->gl_stats.stats[GFS2_LKS_SRTTVARB];