When I am doing benchmarking on ATS I am seeing some requests >= 40ms but the
vast majority are taking <= 1ms. When turning on slow log it looks like the
issue is around cache. is there any option that I can set to mitigate this
issue or anything I can do to dig in deeper to find out where the problems is?
[Jul 31 03:01:57.160] Server {0x2ad695824700} ERROR: [36364408] Slow Request:
url: http://q4.ycpi.bf1.yahoo.net:8124/200_10_0_cache status: 200 unique id:
bytes: 200 fd: 0 client state: 0 server state: 0 ua_begin: 0.000
ua_read_header_done: 0.000 cache_open_read_begin: 0.000 cache_open_read_end:
0.040 dns_lookup_begin: -1.000 dns_lookup_end: -1.000 server_connect: -1.000
server_first_read: -1.000 server_read_header_done: -1.000 server_close: -1.000
ua_close: 0.040 sm_finish: 0.040
[Jul 31 03:01:58.440] Server {0x2ad695824700} ERROR: [36556479] Slow Request:
url: http://q4.ycpi.bf1.yahoo.net:8124/200_10_0_cache status: 200 unique id:
bytes: 200 fd: 0 client state: 0 server state: 0 ua_begin: 0.000
ua_read_header_done: 0.000 cache_open_read_begin: 0.000 cache_open_read_end:
0.040 dns_lookup_begin: -1.000 dns_lookup_end: -1.000 server_connect: -1.000
server_first_read: -1.000 server_read_header_done: -1.000 server_close: -1.000
ua_close: 0.040 sm_finish: 0.040
Here are the results of the benchmark. This occurs in less then 1% of the
responses:
[client bcall@q1 bench]$ fbench -s 120 -c 2 -n 200 -q "200_%d.query"
q2.ycpi.bf1.yahoo.net 8080
Starting clients...
[dummydate]: PROGRESS: fbench: Seconds left 120
[dummydate]: PROGRESS: fbench: Seconds left 60
Stopping
clients........................................................................................................................................................................................................
Clients stopped.
*** HTTP keep-alive statistics ***
connection reuse count -- 17774265
***************** Benchmark Summary *****************
clients: 200
ran for: 120 seconds
cycle time: 2 ms
lower response limit: 0 bytes
skipped requests: 0
failed requests: 0
successful requests: 17774465
cycles not held: 20219
minimum response time: 0.09 ms
maximum response time: 84.21 ms
average response time: 0.29 ms
25 percentile: 0.00 ms
50 percentile: 0.00 ms
75 percentile: 0.00 ms
90 percentile: 0.00 ms
95 percentile: 0.00 ms
99 percentile: 1.00 ms
actual query rate: 148175.09 Q/s
utilization: 21.41 %
zero hit queries: 0
-Bryan
