On Thu, Mar 01, 2007 at 12:41:37PM +0100, Ingo Molnar ([EMAIL PROTECTED]) wrote: > > * Evgeniy Polyakov <[EMAIL PROTECTED]> wrote: > > > I also changed client socket to nonblocking mode with the same result > > in epoll server. If you will find it broken, please send me corrected > > to test too. > > this line in evserver_kevent.c looks a bit fishy: > > err = recv(s, buf, 100, 0); > > because on the evserver_epoll.c side the following is done: > > err = recv(s, buf, 4096, 0); > > now, for 'ab', the request size is 76 bytes, so it should fit fine > functionality-wise. But, the TCP stack might decide differently of > whether to return with a partial packet depending on how much data is > requested. I dont know whether it actually makes a difference in the TCP > flow decisions, and whether it makes a performance difference in your > test, but safest would be to use 4096 in both cases.
Well, that would be quite strange - as far as I known linux network stack (for which kevent was originally created to support network AIO), there should not be any difference. Anyway, I've reran the test with the same values: # ab -c8000 -n80000 http://192.168.0.48/ This is ApacheBench, Version 2.0.40-dev <$Revision: 1.146 $> apache-2.0 Copyright 1996 Adam Twiss, Zeus Technology Ltd, http://www.zeustech.net/ Copyright 2006 The Apache Software Foundation, http://www.apache.org/ Benchmarking 192.168.0.48 (be patient) Completed 8000 requests Completed 16000 requests Completed 24000 requests Completed 32000 requests Completed 40000 requests Completed 48000 requests Completed 56000 requests Completed 64000 requests Completed 72000 requests Finished 80000 requests Server Software: Apache/1.3.27 Server Hostname: 192.168.0.48 Server Port: 80 Document Path: / Document Length: 3521 bytes Concurrency Level: 8000 Time taken for tests: 18.398381 seconds Complete requests: 80000 Failed requests: 0 Write errors: 0 Total transferred: 338738048 bytes HTML transferred: 308031164 bytes Requests per second: 4348.21 [#/sec] (mean) Time per request: 1839.838 [ms] (mean) Time per request: 0.230 [ms] (mean, across all concurrent requests) Transfer rate: 17979.73 [Kbytes/sec] received Connection Times (ms) min mean[+/-sd] median max Connect: 148 795 196.9 808 3599 Processing: 824 882 39.7 878 986 Waiting: 59 426 212.6 423 914 Total: 1073 1678 200.8 1673 4579 Percentage of the requests served within a certain time (ms) 50% 1673 66% 1674 75% 1678 80% 1686 90% 1852 95% 1861 98% 1864 99% 1865 100% 4579 (longest request) Essentially the same result (in limits of some inaccuracy). > in general, please make sure the exact same system calls are done in the > client function. (except of course for the event queueing syscalls > themselves) Yes, that should be done of course. I even have a plan to create the same binary for both, but have also in plans to turn some kevent optimization (mainly readiness-on-submit, when requested event (secv/send/anything) is ready immediately - kevent supports to return that event in the submission syscall without additional overhead by reading it from ring or queue). > Ingo -- Evgeniy Polyakov - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
