SUMMARY: DNLC hit rate

Peter Schauss x 2014 (ps4330@okc01.jccbi.gov)
Thu, 05 Feb 1998 12:52:45 -0500

Two more very usefull responses to my original question:

From: Daniel Dunn <dunn@sled.gsfc.nasa.gov>

vmstat -s will give you the number of name lookups
and the hit rate. The amount of RAM in the system
determines the default value.

Check out http://www.docs.sun.com. Choose the system
administration option then do a search for dnlc.

The best source though is to search
http://www.sun.com/sunworldonline/sun.index.html for
past articles by Adrian Cockcroft. Or get his
past articles by Adrian Cockcroft. Or get his
sun performance book.

and:

From: Karl Vogel <vogelke@c17mis.region2.wpafb.af.mil>

#!/bin/sh
#
# $Id: dnlc,v 1.2 1995/02/27 04:42:24 vogelke Exp $
# $Source: /usr4/cdc/vogelke/projects/tuning/RCS/dnlc,v $
#
# NAME:
# dnlc
#
# DESCRIPTION:
# "dnlc" reports on Directory name lookup cache statistics from
# the kernel. This corrects a bug in vmstat.
#
# AUTHOR:
# Kimberley Brown - UKAC Kernel Support
# comp.unix.solaris

PATH=/bin:/usr/bin:/usr/local/bin
export PATH

adb -k /dev/ksyms /dev/mem <<END
="** Directory/Inode Cache Statistics **"
="----------------------------------------"
ufs_ninode/D"Inode cache size"
ncsize/D"Directory name cache size"
ncstats/D"# of cache hits that we used"
+/D"# of misses"
+/D"# of enters done"
+/D"# of enters tried when already cached"
+/D"# of long names tried to enter"
+/D"# of long name tried to look up"
+/D"# of times LRU list was empty"
+/D"# of purges of cache"
*ncstats%1000>a
*(ncstats+4)%1000>b
*(ncstats+14)%1000>c
<a+<b+<c>n
<a*0t100%<n=D"Hit rate percentage"
="(See /usr/include/sys/dnlc.h for more information)"
END

exit 0

Thanks to everyone.

Peter Schauss
ps4330@okc01.jccbi.gov
Gull Electronic Systems Division
Parker Hannifin Corporation
Smithtown, NY