Messages in this thread | | | Date | Thu, 12 Aug 2004 22:45:50 +1000 | From | Omar Kilani <> | Subject | Performance Degradation: 2.6.8-rc4-bk1 vs RHEL 2.4.21-15.0.3 |
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List,
I'm doing some "benchmarking" using ApacheBench against a bunch of different operating systems and kernel versions, and noticed what appears (by appears I mean "this may be intended behavior that I am not aware of") a severe performance degradation between 2.4 and 2.6.
In this case, I'm testing the same version of Apache (2.0.50) on the same hardware, using my own distributions (one is 2.4 based and uses the RHEL 2.4.21-15.0.3 kernel, the other is 2.6 based and uses 2.6.8-rc3, although 2.6.8-rc4-bk1 exhibits the same issues.)
Hardware: Pentium 4 2.8GHz HT (running the SMP kernel) with 512MB of RAM, and an 80Gb WD HDD.
Some numbers:
2.4.21-2ts:
[root@rio root]# hdparm -T -t /dev/hda
/dev/hda: Timing buffer-cache reads: 2316 MB in 2.00 seconds = 1158.00 MB/sec Timing buffered disk reads: 176 MB in 3.01 seconds = 58.47 MB/sec
[root@rio i686-pc-linux-gnu]# ./bw_tcp -s [root@rio i686-pc-linux-gnu]# ./bw_tcp 127.0.0.1 0.065536 1284.40 MB/sec [root@rio i686-pc-linux-gnu]# ./bw_tcp 127.0.0.1 0.065536 828.20 MB/sec [root@rio i686-pc-linux-gnu]# ./bw_tcp 127.0.0.1 0.065536 1346.99 MB/sec [root@rio i686-pc-linux-gnu]# ./bw_tcp 127.0.0.1 0.065536 1372.90 MB/sec [root@rio i686-pc-linux-gnu]# ./bw_tcp 127.0.0.1 0.065536 871.46 MB/sec
[root@rio root]# ab -n 100000 -c 2 http://localhost/index.html This is ApacheBench, Version 2.0.40-dev <$Revision: 1.141 $> apache-2.0 Copyright (c) 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Copyright (c) 1998-2002 The Apache Software Foundation, http://www.apache.org/
Benchmarking localhost (be patient) Completed 10000 requests Completed 20000 requests Completed 30000 requests Completed 40000 requests Completed 50000 requests Completed 60000 requests Completed 70000 requests Completed 80000 requests Completed 90000 requests Finished 100000 requests
Server Software: Apache/2.0.50 Server Hostname: localhost Server Port: 80
Document Path: /index.html Document Length: 51200 bytes
Concurrency Level: 2 Time taken for tests: 34.37600 seconds Complete requests: 100000 Failed requests: 0 Write errors: 0 Total transferred: 852584179 bytes HTML transferred: 825083904 bytes Requests per second: 2937.93 [#/sec] (mean) Time per request: 0.681 [ms] (mean) Time per request: 0.340 [ms] (mean, across all concurrent requests) Transfer rate: 24461.21 [Kbytes/sec] received
Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.0 0 1 Processing: 0 0 0.0 0 5 Waiting: 0 0 0.0 0 2 Total: 0 0 0.0 0 5
Percentage of the requests served within a certain time (ms) 50% 0 66% 0 75% 0 80% 0 90% 0 95% 0 98% 0 99% 0 100% 5 (longest request)
Multiple runs of ab produce similar results.
2.6.8-rc4-bk1:
[root@odin vm]# hdparm -T -t /dev/hda
/dev/hda: Timing buffer-cache reads: 2384 MB in 2.00 seconds = 1192.18 MB/sec Timing buffered disk reads: 124 MB in 3.01 seconds = 41.20 MB/sec
[root@odin i686-pc-linux-gnu]# ./bw_tcp -s [root@odin i686-pc-linux-gnu]# ./bw_tcp 127.0.0.1 0.065536 404.62 MB/sec
(Ran this 5 times with no real difference between runs.)
[root@odin ~]# ab -n 100000 -c 2 http://localhost/index.html This is ApacheBench, Version 2.0.40-dev <$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: 54.895184 seconds Complete requests: 100000 Failed requests: 0 Write errors: 0 Total transferred: 852032704 bytes HTML transferred: 825032704 bytes Requests per second: 1821.65 [#/sec] (mean) Time per request: 1.098 [ms] (mean) Time per request: 0.549 [ms] (mean, across all concurrent requests) Transfer rate: 15157.30 [Kbytes/sec] received
Connection Times (ms) min mean[+/-sd] median max Connect: 0 0 0.2 0 47 Processing: 0 0 0.6 0 55 Waiting: 0 0 0.2 0 54 Total: 0 0 0.6 0 55
Percentage of the requests served within a certain time (ms) 50% 0 66% 0 75% 0 80% 0 90% 0 95% 1 98% 1 99% 1 100% 55 (longest request)
Multiple runs of ab produce the same results.
So it seems to me that IDE performance (chipset is ICH5) has decreased, as well as net loopback performance, and this may be the cause of the performance degradation.
Are there any known issues with either of these? What else could be effecting these results?
Please Advise.
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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