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authorsjg <sjg@FreeBSD.org>2015-05-27 01:19:58 +0000
committersjg <sjg@FreeBSD.org>2015-05-27 01:19:58 +0000
commit65145fa4c81da358fcbc3b650156dab705dfa34e (patch)
tree55c065b6730aaac2afb6c29933ee6ec5fa4c4249 /lib/libdevstat
parent60ff4eb0dff94a04d75d0d52a3957aaaf5f8c693 (diff)
parente6b664c390af88d4a87208bc042ce503da664c3b (diff)
downloadFreeBSD-src-65145fa4c81da358fcbc3b650156dab705dfa34e.zip
FreeBSD-src-65145fa4c81da358fcbc3b650156dab705dfa34e.tar.gz
Merge sync of head
Diffstat (limited to 'lib/libdevstat')
-rw-r--r--lib/libdevstat/Makefile3
-rw-r--r--lib/libdevstat/devstat.c24
2 files changed, 4 insertions, 23 deletions
diff --git a/lib/libdevstat/Makefile b/lib/libdevstat/Makefile
index aeb07b9..dcda3c2 100644
--- a/lib/libdevstat/Makefile
+++ b/lib/libdevstat/Makefile
@@ -7,8 +7,7 @@ SHLIB_MAJOR= 7
SRCS= devstat.c
INCS= devstat.h
-DPADD= ${LIBKVM}
-LDADD= -lkvm
+LIBADD= kvm
MAN= devstat.3
diff --git a/lib/libdevstat/devstat.c b/lib/libdevstat/devstat.c
index ade8738..d52332b 100644
--- a/lib/libdevstat/devstat.c
+++ b/lib/libdevstat/devstat.c
@@ -1487,22 +1487,9 @@ devstat_compute_statistics(struct devstat *current, struct devstat *previous,
*destld = 0.0;
break;
/*
- * This calculation is somewhat bogus. It simply divides
- * the elapsed time by the total number of transactions
- * completed. While that does give the caller a good
- * picture of the average rate of transaction completion,
- * it doesn't necessarily give the caller a good view of
- * how long transactions took to complete on average.
- * Those two numbers will be different for a device that
- * can handle more than one transaction at a time. e.g.
- * SCSI disks doing tagged queueing.
- *
- * The only way to accurately determine the real average
- * time per transaction would be to compute and store the
- * time on a per-transaction basis. That currently isn't
- * done in the kernel, and would only be desireable if it
- * could be implemented in a somewhat non-intrusive and high
- * performance way.
+ * Some devstat callers update the duration and some don't.
+ * So this will only be accurate if they provide the
+ * duration.
*/
case DSM_MS_PER_TRANSACTION:
if (totaltransfers > 0) {
@@ -1512,11 +1499,6 @@ devstat_compute_statistics(struct devstat *current, struct devstat *previous,
} else
*destld = 0.0;
break;
- /*
- * As above, these next two really only give the average
- * rate of completion for read and write transactions, not
- * the average time the transaction took to complete.
- */
case DSM_MS_PER_TRANSACTION_READ:
if (totaltransfersread > 0) {
*destld = totaldurationread;
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