Xref: utzoo comp.unix.wizards:22907 comp.unix.questions:23825
Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!usc!apple!oliveb!orc!inews!quasar.intel.com!kseshadr
From: kseshadr@quasar.intel.com
Newsgroups: comp.unix.wizards,comp.unix.questions
Subject: measuring NFS calls using timers
Message-ID: <2518@inews.intel.com>
Date: 17 Jul 90 21:27:42 GMT
Sender: news@inews.intel.com
Reply-To: kseshadr@quasar.intel.com ()
Organization: Intel Corporation, Santa Clara, California
Lines: 29

workstations on our network. This is sort of in the nhfsstone tradition
except that I want to do this when the workstation is being used. 
Consequently I DON'T want to carry out N (read large N) number of NFS ops,
and calculate the average time to service each request. Ideally I would
like to carry out a single call and time it. This is where I've run into
problems using the profiling timer. I'm doing this on a Sun 386i running
SunOS 4.0.2 and it seems like the NFS call is being completed even before
the timer is decremented. As a result the operation appears to happen in
time 0 (wouldn't that be nice :-). Either I'm doing something wrong or 
SunOS is not very good about microsecond timings. 

Can anyone point me to a good source of information about carrying
out such timings? I don't mind suggestions to RTF parts of the sources
or man pages. I seem to recall some fixes to the nit_if.o file for 
the tcpdump program. The README file that came with the program mentioned
that their version of nit.o gave timestamps to the resolution of the SS-1
clock (1 us) rather than the 20ms timestamps the Sun normally gives. I've
been trying my timings primarily with getattr calls, so its entirely 
possible that the call completes in less that 20 milliseconds (I'm making
sure that I don't hit the attribute cache..). What do I need to do to get
timestamps with microsecond resolution and are there any hardware limitations
with the Sun 386i that would prevent me from being able to do this?

Kishore Seshadri
kishore@mipos3.intel.com
===============================================================================
Kishore Seshadri (Speaking only for myself) Intel Corp., Santa Clara, CA
CSNET: kseshadr@mipos3.intel.com ARPA: kseshadr%mipos3.intel.com@relay.cs.net
UUCP:{amdcad,decwrl,hplabs,oliveb,pur-ee,qantel}!intelca!mipos3!kseshadr