Messages in this thread | | | Date | Thu, 12 Aug 2004 23:35:35 +1000 | From | Omar Kilani <> | Subject | Re: Performance Degradation: 2.6.8-rc4-bk1 vs RHEL 2.4.21-15.0.3 |
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Maciej,
On Thu, 12 Aug 2004 15:09:22 +0200, Maciej Soltysiak <solt@dns.toxicfilms.tv> wrote: > Hi, > > Just a wild guess, please try the same tests with 2.6 kernels with > echo 0 > /proc/sys/net/ipv4/tcp_window_scaling
This halves all my performance values.
I've just tried 2.6.8-rc4-mm1 with the same results.
I also tested the 2.6.8-rc4-mm1 kernel on a dual P4 Xeon 3.2GHz with 2MB Cache (with HT, so 4 logical processors) using 15K RPM U320 Fujitsu SCSI drives.
[root@minbar root]# hdparm -T -t /dev/sda
/dev/sda: Timing buffer-cache reads: 1852 MB in 2.00 seconds = 927.07 MB/sec Timing buffered disk reads: 218 MB in 3.02 seconds = 72.29 MB/sec
[root@minbar root]# ./bw_tcp 127.0.0.1 0.065536 333.85 MB/sec
Ran this 5 times with no real difference in value.
[root@minbar root]# ab -n 100000 -c 2 http://localhost/index.html This is ApacheBench, Version 2.0.40-dev <$Revision: 1.141 $> apache-2.0 Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Copyright (c) 1998-2002 The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient) Completed 10000 requests Completed 20000 requests Completed 30000 requests Completed 40000 requests Completed 50000 requests Completed 60000 requests Completed 70000 requests Completed 80000 requests Completed 90000 requests Finished 100000 requests
Server Software: Apache/2.0.50 Server Hostname: localhost Server Port: 80
Document Path: /index.html Document Length: 51200 bytes
Concurrency Level: 2 Time taken for tests: 43.787872 seconds Complete requests: 100000 Failed requests: 0 Write errors: 0 Total transferred: 852032704 bytes HTML transferred: 825032704 bytes Requests per second: 2283.74 [#/sec] (mean) Time per request: 0.876 [ms] (mean) Time per request: 0.438 [ms] (mean, across all concurrent requests) Transfer rate: 19002.13 [Kbytes/sec] received
Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.0 0 0 Processing: 0 0 0.1 0 12 Waiting: 0 0 0.0 0 1 Total: 0 0 0.1 0 12
Percentage of the requests served within a certain time (ms) 50% 0 66% 0 75% 0 80% 0 90% 0 95% 0 98% 0 99% 0 100% 12 (longest request)
Ran this 5 times with no real difference in performance.
So a single 2.8GHz P4 HT with a 2.4 kernel has better performance than a dual Xeon 3.2GHz HT with a 2.6 kernel. I think the SCSI drives eliminate the IDE results as a factor, so this looks like it's a net loopback performance issue. Maybe. :) > I am curious if it might be related to my problems with networking. > turning of TCP WS tcp_window_scaling helps my problems. > > Regards, > Maciej
Regards, Omar Kilani - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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