svn commit: r319866 - head/usr.bin/top

[Allan Jude]

Author: allanjude
Date: Mon Jun 12 19:51:57 2017
New Revision: 319866
URL: https://svnweb.freebsd.org/changeset/base/319866

Log:
  top: Change the way the ZFS ARC compression ratio is calculated
  
  Based on feedback from OpenZFS developers Matt Ahrens and George Wilson,
  the calculation of the ratio no longer takes in to account overhead.
  
  The old formula could result in reporting a negative compression ratio
  
  This could confuse the user or give a false impression that there would be
  an advantage to disabling the compressed ARC feature.
  
  The new formula will more closely match an average of the on-disk
  compression ratio, as reported by the ZFS property 'compressratio'
  
  MFC after:	3 days
  Sponsored by:	ScaleEngine Inc.

Modified:
  head/usr.bin/top/machine.c

Modified: head/usr.bin/top/machine.c
==============================================================================
--- head/usr.bin/top/machine.c	Mon Jun 12 19:45:05 2017	(r319865)
+++ head/usr.bin/top/machine.c	Mon Jun 12 19:51:57 2017	(r319866)
@@ -188,9 +188,9 @@ char *arcnames[] = {
 	NULL
 };
 
-int carc_stats[5];
+int carc_stats[4];
 char *carcnames[] = {
-	"K Compressed, ", "K Uncompressed, ", ":1 Ratio, ", "K Overhead",
+	"K Compressed, ", "K Uncompressed, ", ":1 Ratio, ",
 	NULL
 };
 
@@ -580,11 +580,9 @@ get_system_info(struct system_info *si)
 	if (carc_enabled) {
 		GETSYSCTL("kstat.zfs.misc.arcstats.compressed_size", arc_stat);
 		carc_stats[0] = arc_stat >> 10;
+		carc_stats[2] = arc_stat >> 10; /* For ratio */
 		GETSYSCTL("kstat.zfs.misc.arcstats.uncompressed_size", arc_stat);
 		carc_stats[1] = arc_stat >> 10;
-		carc_stats[2] = arc_stats[0]; /* ARC Total */
-		GETSYSCTL("kstat.zfs.misc.arcstats.overhead_size", arc_stat);
-		carc_stats[3] = arc_stat >> 10;
 		si->carc = carc_stats;
 	}