From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <873f624fc38d170af86a6dcae4bcedcf@quanstro.net>
From: erik quanstrom <quanstro@quanstro.net>
Date: Thu, 21 Sep 2006 18:59:39 -0500
To: 9fans@cse.psu.edu
Subject: Re: [9fans] Re: venti+fossil problems on new install
In-Reply-To: <d0b8b643dcd3204898769b77140adc6d@plan9.bell-labs.com>
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here's another interesting performance result that i don't understand:

	ladd# ls -l shot.img
	ladd# time rc -c '{for(i in `{seq 1 100}) cat shot.img}>/dev/null' & time rc -c '{for(i in `{seq 1 100}) cat shot.img}>/dev/null' 
	0.04u 0.82s 36.07r 	 rc -c {for(i in `{seq 1 100}) cat shot.img}>/dev/null
	--rw-rw-r-- M 59 quanstro quanstro 5242940 Jul 22 13:56 shot.img
	ladd# time rc -c '{for(i in `{seq 1 100}) cat shot.img}>/dev/null' & time rc -c '{for(i in `{seq 1 100}) cat shot.img}>/dev/null' 
	0.04u 1.65s 37.82r 	 rc -c {for(i in `{seq 1 100}) cat shot.img}>/dev/null
	0.02u 1.34s 37.83r 	 rc -c {for(i in `{seq 1 100}) cat shot.img}>/dev/null
	
wall clock time was 38s. this works out 14MB/s and 14MB/s*2.  that is, neither the network
card nor my slow fs can be the bottleneck.  even 28MB/s is only 228Mbit/sec, so we're not close
to the network bandwidth. could something be rate limiting itself at a close to
100Mbit/sec per connection?

- erik