I've been complaining about these problems for a bit, so I thought I'd
share some good news.
http://marc.theaimsgroup.com/?l=linux-netdev&m=104169568212878&w=2
http://marc.theaimsgroup.com/?t=104343403700001&r=1&w=2
I decided to spend some time tracking down the TCP stalls that I was
still seeing with the e1000 on 2.5.59 (probably not the e1000's fault,
just the only cards I see it on). I pulled out my trusty old test that
I've been using for a few weeks to replicate the problem. Anyway, I
can't get it to occur any more. The real test will be to see if Specweb
still triggers it, but my Specweb machine is a smoldering pile of slag
right now.
I have a 4-way PIII-Xeon and an 8-way PIII-Xeon plugged into the same
copper gigabit switch. The 4-way runs 4 copies of http-bench.sh, which
I've included below. It basically asks the server for a list of files
(from a cgi script), then fetches them sequentially. The _sustained_
data rate is 750 Mb/sec with peaks of ~790 Mb/sec. The server runs
Apache 2.0.43.
During this time, the client is about 80% CPU saturated (shell scripts,
what do you expect?), but the server is a much different story. vmstat
shows ~1% user time, and only 5-6% kernel. The rest is idle! I have
readprofile from a short slice, because oprofile doesn't work on these
machines.
126 tcp_write_xmit 0.1703
128 kfree 1.2800
131 __kfree_skb 0.6550
132 ip_rcv 0.1303
142 qdisc_restart 0.3550
150 tcp_transmit_skb 0.1053
156 schedule 0.1566
161 e1000_clean_rx_irq 0.1720
169 kmalloc 1.2426
189 skb_clone 0.4500
215 alloc_skb 0.4594
233 do_generic_mapping_read 0.2709
240 tcp_v4_rcv 0.1268
294 e1000_intr 3.1957
311 e1000_clean_tx_irq 0.7266
353 e1000_xmit_frame 0.2229
370 do_tcp_sendpages 0.1370
408 skb_release_data 2.6154
127279 poll_idle 1515.2262
134275 total 0.0829
httpd-bench.sh:
#!/bin/sh
SERVER=10.1.1.96
rm -f file_list 2> /dev/null
wget -O file_list http://$SERVER/ls.pl
cat file_list | \
awk '{print "http://'$SERVER'/" $0}' | \
xargs --max-procs=1 --max-args=20 wget -O /dev/null --progress=dot 2>&1
| grep \'" saved " \
| awk -f speedavg.awk
ls.pl from the server (yeah, yeah, I know it's not perl, but I didn't
feel like adding another handler)
#!/bin/sh
echo 'Content-type: text/html'
echo
find file_set -type f -size +100k
--
Dave Hansen
haveblue@xxxxxxxxxx
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