Re: [patch 00/13] Syslets, "Threadlets", generic AIO support, v3

From: David Lang
Date: Thu Mar 01 2007 - 12:18:16 EST


the ab numbers below do not seem that impressive to me, especially for such stripped down server processes.

here are some numbers from a set of test boxes I've got in my lab. I've been useing them to test firewalls, and I've been getting throughput similar to what is listed below when going through a proxy that does a full fork for each connection, and then makes a new connection to the webserver on the other side! the first few sets of numbers are going directly from test client to test server, the final set is going though the proxy.

client and server are dual opteron 252 with 8G of ram, running debian in 64 bit mode

this is with apache2 MPM as the destination (relativly untuned except for tinkering with the child count settings). this should be about as bad as you can get for a server

loadtest2:/proc/sys# ab -c 8000 -n 80000 http://208.2.188.5:80/4k
This is ApacheBench, Version 2.0.41-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 208.2.188.5 (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/1.3.33
Server Hostname: 208.2.188.5
Server Port: 80

Document Path: /4k
Document Length: 4352 bytes

Concurrency Level: 8000
Time taken for tests: 10.992838 seconds
Complete requests: 80000
Failed requests: 0
Write errors: 0
Total transferred: 386192835 bytes
HTML transferred: 362612992 bytes
Requests per second: 7277.47 [#/sec] (mean)
Time per request: 1099.284 [ms] (mean)
Time per request: 0.137 [ms] (mean, across all concurrent requests)
Transfer rate: 34307.88 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 8 497 1398.3 71 9072
Processing: 17 236 346.9 103 2995
Waiting: 8 91 131.6 65 1692
Total: 26 734 1435.5 187 9786

Percentage of the requests served within a certain time (ms)
50% 187
66% 288
75% 564
80% 754
90% 3085
95% 3163
98% 4316
99% 9186
100% 9786 (longest request)
loadtest2:/proc/sys# ab -c 8000 -n 80000 http://208.2.188.5:80/8k
This is ApacheBench, Version 2.0.41-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 208.2.188.5 (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/1.3.33
Server Hostname: 208.2.188.5
Server Port: 80

Document Path: /8k
Document Length: 8704 bytes

Concurrency Level: 8000
Time taken for tests: 11.355031 seconds
Complete requests: 80000
Failed requests: 0
Write errors: 0
Total transferred: 736949141 bytes
HTML transferred: 713733802 bytes
Requests per second: 7045.34 [#/sec] (mean)
Time per request: 1135.503 [ms] (mean)
Time per request: 0.142 [ms] (mean, across all concurrent requests)
Transfer rate: 63379.48 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 36 495 1297.1 76 9056
Processing: 81 317 529.5 161 3448
Waiting: 25 89 75.1 76 1610
Total: 124 812 1401.5 250 11011

Percentage of the requests served within a certain time (ms)
50% 250
66% 304
75% 497
80% 705
90% 3171
95% 3251
98% 3455
99% 9160
100% 11011 (longest request)

for both of these tests the server had it's cpu maxed out (<5% idle)

switching to thttpd instead of apache and I get

loadtest2:/proc/sys# ab -c 8000 -n 80000 http://208.2.188.5:81/4k
This is ApacheBench, Version 2.0.41-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 208.2.188.5 (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: thttpd/2.23beta1
Server Hostname: 208.2.188.5
Server Port: 81

Document Path: /4k
Document Length: 4352 bytes

Concurrency Level: 8000
Time taken for tests: 9.944605 seconds
Complete requests: 80000
Failed requests: 0
Write errors: 0
Total transferred: 372748950 bytes
HTML transferred: 352729600 bytes
Requests per second: 8044.56 [#/sec] (mean)
Time per request: 994.461 [ms] (mean)
Time per request: 0.124 [ms] (mean, across all concurrent requests)
Transfer rate: 36603.97 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 50 324 1274.4 70 9124
Processing: 68 98 33.3 90 781
Waiting: 22 69 26.9 63 729
Total: 125 423 1291.9 161 9324

Percentage of the requests served within a certain time (ms)
50% 161
66% 175
75% 188
80% 203
90% 246
95% 307
98% 3243
99% 9272
100% 9324 (longest request)
loadtest2:/proc/sys# ab -c 8000 -n 80000 http://208.2.188.5:81/8k
This is ApacheBench, Version 2.0.41-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 208.2.188.5 (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: thttpd/2.23beta1
Server Hostname: 208.2.188.5
Server Port: 81

Document Path: /8k
Document Length: 8704 bytes

Concurrency Level: 8000
Time taken for tests: 13.502031 seconds
Complete requests: 80000
Failed requests: 0
Write errors: 0
Total transferred: 729161888 bytes
HTML transferred: 709030153 bytes
Requests per second: 5925.03 [#/sec] (mean)
Time per request: 1350.203 [ms] (mean)
Time per request: 0.169 [ms] (mean, across all concurrent requests)
Transfer rate: 52738.14 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 46 338 1189.7 106 9145
Processing: 79 197 52.8 195 670
Waiting: 39 92 28.4 94 577
Total: 140 536 1208.3 293 9424

Percentage of the requests served within a certain time (ms)
50% 293
66% 350
75% 355
80% 369
90% 388
95% 3293
98% 3388
99% 9392
100% 9424 (longest request)

for these the CPU is ~45% idle on the server box.

now if I go through a box in the middle running a proxy that forks for every request (so you have two seperate TCP connections, plus a fork for each request plus two writes to syslog) the proxy box is a dual opteron 252 with 4G or ram running debian 32 bit

loadtest2:/proc/sys# ab -c 8000 -n 80000 http://192.168.254.2:8080/8k
This is ApacheBench, Version 2.0.41-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 192.168.254.2 (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/1.3.33
Server Hostname: 192.168.254.2
Server Port: 8080

Document Path: /8k
Document Length: 8704 bytes

Concurrency Level: 8000
Time taken for tests: 21.101321 seconds
Complete requests: 80000
Failed requests: 0
Write errors: 0
Total transferred: 721092650 bytes
HTML transferred: 698383315 bytes
Requests per second: 3791.23 [#/sec] (mean)
Time per request: 2110.132 [ms] (mean)
Time per request: 0.264 [ms] (mean, across all concurrent requests)
Transfer rate: 33371.94 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 9 621 1652.3 20 9036
Processing: 28 81 195.5 50 6652
Waiting: 9 51 195.5 19 6620
Total: 38 703 1683.2 70 12291

Percentage of the requests served within a certain time (ms)
50% 70
66% 80
75% 83
80% 101
90% 3075
95% 3088
98% 9073
99% 9087
100% 12291 (longest request)

David Lang





On Thu, 1 Mar 2007, Evgeniy Polyakov wrote:

On Thu, Mar 01, 2007 at 10:54:02AM +0100, Ingo Molnar (mingo@xxxxxxx) wrote:

* Evgeniy Polyakov <johnpol@xxxxxxxxxxx> wrote:

I posted kevent/epoll benchmarks and related design issues too many
times both with handmade applications (which might be broken as hell)
and popular open-source servers to repeat them again.

numbers are crutial here - and given the epoll bugs in the evserver code
that we found, do you have updated evserver benchmark results that
compare epoll to kevent? I'm wondering why epoll has half the speed of
kevent in those measurements - i suspect some possible benchmarking bug.
The queueing model of epoll and kevent is roughly comparable, both do
only a constant number of steps to serve one particular request,
regardless of how many pending connections/requests there are. What is
the CPU utilization of the server system during an epoll test, and what
is the CPU utilization during a kevent test? 100% utilized in both
cases?

Yes, it is about 98-100% in both cases.
I've just re-run tests on my amd64 test machine without debug options:

epoll 4794.23
kevent 6468.95

here are full client 'ab' outputs for epoll and kevent servers (epoll
does not contain EPOLLET as you requested, but it does not look like
it change performance in my case).

epoll ab aoutput:
# 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: 16.686737 seconds
Complete requests: 80000
Failed requests: 0
Write errors: 0
Total transferred: 309760000 bytes
HTML transferred: 281680000 bytes
Requests per second: 4794.23 [#/sec] (mean)
Time per request: 1668.674 [ms] (mean)
Time per request: 0.209 [ms] (mean, across all concurrent
requests)
Transfer rate: 18128.17 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 159 779 110.1 799 921
Processing: 468 866 77.4 869 988
Waiting: 63 426 212.3 425 921
Total: 1145 1646 115.6 1660 1873

Percentage of the requests served within a certain time (ms)
50% 1660
66% 1661
75% 1662
80% 1663
90% 1806
95% 1830
98% 1833
99% 1834
100% 1873 (longest request)

kevent ab output:
# 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: 12.366775 seconds
Complete requests: 80000
Failed requests: 0
Write errors: 0
Total transferred: 317047104 bytes
HTML transferred: 288306522 bytes
Requests per second: 6468.95 [#/sec] (mean)
Time per request: 1236.677 [ms] (mean)
Time per request: 0.155 [ms] (mean, across all concurrent
requests)
Transfer rate: 25036.12 [Kbytes/sec] received

Connection Times (ms)
min mean[+/-sd] median max
Connect: 130 364 871.1 275 9347
Processing: 178 298 42.5 296 580
Waiting: 31 202 65.8 210 369
Total: 411 663 887.0 572 9722

Percentage of the requests served within a certain time (ms)
50% 572
66% 573
75% 618
80% 640
90% 684
95% 709
98% 721
99% 3455
100% 9722 (longest request)

Notice how percentage of the requests served within a certain time
differs for kevent and epoll. And this server does not include
ready-on-submission kevent optimization.

Ingo


-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/