Poor performance on proxied requests which are not cacheable.
-------------------------------------------------------------
Key: TS-506
URL: https://issues.apache.org/jira/browse/TS-506
Project: Traffic Server
Issue Type: Bug
Components: Cache
Reporter: Leif Hedstrom
Fix For: 2.1.4
This is a problem similar in behavior and how to reproduce as TS-505.
I have a test setup using lighttpd (stock config, but with the port changed to
port 82, and logging disabled). I've also disabled Keep-Alive on lighttpd, with
a line like this in /etc/lighttpd/lighttpd.conf
server.max-keep-alive-requests = 0
I've created a small file (42 bytes) in /var/www/lighttpd/cl-test.html.
I'm running Apache TS with a stock config ("gmake install") with the following
configuration changes:
records.config:
---------------
CONFIG proxy.config.http.server_port INT 80
CONFIG proxy.config.http.cache.required_headers INT 2
CONFIG proxy.config.log2.logging_enabled INT 0
remap.config:
-------------
map http://loki.ogre.com/lighttpd/ http://localhost:82/
I'm "benchmarking" this using "ab" from a second host, running a command like
ab -c 20 -n 10000 http://loki.ogre.com/lighttpd/cl-test.html
Test 1: http caching is disabled with a records.config setting
CONFIG proxy.config.http.cache.http INT 0
Results:
Requests per second: 9319.75 [#/sec] (mean)
Time per request: 2.146 [ms] (mean)
Time per request: 0.107 [ms] (mean, across all concurrent requests)
Test 2: http caching enabled, records.config is
CONFIG proxy.config.http.cache.http INT 0
Results:
Requests per second: 2967.59 [#/sec] (mean)
Time per request: 6.739 [ms] (mean)
Time per request: 0.337 [ms] (mean, across all concurrent requests)
So, simply enabling the cache makes it process 3x less QPS and at 3x the
latency. There is again no disk I/O on either of these tests.
If I "combine" the worst case scenario, from TS-505 and this bug, and run the
test with http.cache=1 (cache enabled) and have the lighttpd server send
Connection: keep-alive responses, the performance plunges:
Requests per second: 173.09 [#/sec] (mean)
Time per request: 115.548 [ms] (mean)
Time per request: 5.777 [ms] (mean, across all concurrent requests)
--
This message is automatically generated by JIRA.
-
You can reply to this email to add a comment to the issue online.
