做个标记:)
Httperf is a tool for measuring web server performance. It provides a flexible facility for generating various HTTP workloads and for measuring server performance. The focus of httperf is not on implementing one particular benchmark but on providing a robust, high-performance tool that facilitates the construction of both micro- and macro-level benchmarks. The three distinguishing characteristics of httperf are its robustness, which includes the ability to generate and sustain server overload, support for the HTTP/1.1 and SSL protocols, and its extensibility to new workload generators and performance measurements.
Httperf 是一个高效的 http 压力测试工具，使用它可以模拟出超过1千的并发访问，能充分测试出 web server 的性能。而之前使用的 siege 测试工具则未能突破 500 个并发测试（如果您知道如何可以实现，请告诉我）
使用 httperf 应该能了解到自己编写 yo2cache 软件性能极限如何了 
以下是 gzip 格式访问的测试数据（因缓存文件以 gzip 格式保存，所以性能是最高的）
oneoo@oneoo-pc:~/Desktop$ httperf –server oneoo.com –num-conns 2000 –add-header “accept-encoding: gzip”
httperf –client=0/1 –server=oneoo.com –port=80 –uri=/ –send-buffer=4096 –recv-buffer=16384 –add-header=’accept-encoding: gzip’ –num-conns=2000 –num-calls=1
Maximum connect burst length: 1Total: connections 2000 requests 2000 replies 2000 test-duration 1.304 s
Connection rate: 1533.7 conn/s (0.7 ms/conn,
Connection time [ms]: min 0.6 avg 0.7 max 6.3 median 0.5 stddev 0.2
Connection time [ms]: connect 0.0
Connection length [replies/conn]: 1.000Request rate: 1533.7 req/s (0.7 ms/req)
Request size [B]: 81.0Reply rate [replies/s]: min 0.0 avg 0.0 max 0.0 stddev 0.0 (0 samples)
Reply time [ms]: response 0.6 transfer 0.0
Reply size [B]: header 302.0 content 10482.0 footer 0.0 (total 10784.0)
Reply status: 1xx=0 2xx=2000 3xx=0 4xx=0 5xx=0CPU time [s]: user 0.29 system 1.01 (user 22.4% system 77.6% total 100.0%)
Net I/O: 16273.4 KB/s (133.3*10^6 bps)Errors: total 0 client-timo 0 socket-timo 0 connrefused 0 connreset 0
Errors: fd-unavail 0 addrunavail 0 ftab-full 0 other 0
以下是 deflate (2级压缩率)格式访问的统计数据（需要从 gzip 解压，再压缩为 deflate 的数据处理）
oneoo@oneoo-pc:~/Desktop$ httperf –server oneoo.com –num-conns 2000 –add-header “accept-encoding: deflate”
httperf –client=0/1 –server=oneoo.com –port=80 –uri=/ –send-buffer=4096 –recv-buffer=16384 –add-header=’accept-encoding: deflate’ –num-conns=2000 –num-calls=1
Maximum connect burst length: 1Total: connections 2000 requests 2000 replies 2000 test-duration 4.113 s
Connection rate: 486.2 conn/s (2.1 ms/conn,
Connection time [ms]: min 2.0 avg 2.1 max 11.8 median 2.5 stddev 0.3
Connection time [ms]: connect 0.0
Connection length [replies/conn]: 1.000Request rate: 486.2 req/s (2.1 ms/req)
Request size [B]: 84.0Reply rate [replies/s]: min 0.0 avg 0.0 max 0.0 stddev 0.0 (0 samples)
Reply time [ms]: response 0.6 transfer 1.5
Reply size [B]: header 305.0 content 11014.0 footer 0.0 (total 11319.0)
Reply status: 1xx=0 2xx=2000 3xx=0 4xx=0 5xx=0CPU time [s]: user 0.91 system 3.20 (user 22.2% system 77.8% total 100.0%)
Net I/O: 5414.3 KB/s (44.4*10^6 bps)Errors: total 0 client-timo 0 socket-timo 0 connrefused 0 connreset 0
Errors: fd-unavail 0 addrunavail 0 ftab-full 0 other 0
以下是 deflate (4级压缩率)格式访问的统计数据
oneoo@oneoo-pc:~/Desktop$ httperf –server oneoo.com –num-conns 2000 –add-header “accept-encoding: deflate”
httperf –client=0/1 –server=oneoo.com –port=80 –uri=/ –send-buffer=4096 –recv-buffer=16384 –add-header=’accept-encoding: deflate’ –num-conns=2000 –num-calls=1
Maximum connect burst length: 1Total: connections 2000 requests 2000 replies 2000 test-duration 5.329 s
Connection rate: 375.3 conn/s (2.7 ms/conn,
Connection time [ms]: min 2.6 avg 2.7 max 32.8 median 2.5 stddev 0.7
Connection time [ms]: connect 0.0
Connection length [replies/conn]: 1.000Request rate: 375.3 req/s (2.7 ms/req)
Request size [B]: 84.0Reply rate [replies/s]: min 374.8 avg 374.8 max 374.8 stddev 0.0 (1 samples)
Reply time [ms]: response 0.6 transfer 2.0
Reply size [B]: header 305.0 content 10457.0 footer 0.0 (total 10762.0)
Reply status: 1xx=0 2xx=2000 3xx=0 4xx=0 5xx=0CPU time [s]: user 1.29 system 4.01 (user 24.2% system 75.2% total 99.4%)
Net I/O: 3975.4 KB/s (32.6*10^6 bps)Errors: total 0 client-timo 0 socket-timo 0 connrefused 0 connreset 0
Errors: fd-unavail 0 addrunavail 0 ftab-full 0 other 0
以下是文本格式访问的统计数据
oneoo@oneoo-pc:~/Desktop$ httperf –server oneoo.com –num-conns 2000 –add-header “accept-encoding: normal”
httperf –client=0/1 –server=oneoo.com –port=80 –uri=/ –send-buffer=4096 –recv-buffer=16384 –add-header=’accept-encoding: normal’ –num-conns=2000 –num-calls=1
Maximum connect burst length: 1Total: connections 2000 requests 2000 replies 2000 test-duration 2.349 s
Connection rate: 851.3 conn/s (1.2 ms/conn,
Connection time [ms]: min 1.1 avg 1.2 max 5.8 median 1.5 stddev 0.2
Connection time [ms]: connect 0.0
Connection length [replies/conn]: 1.000Request rate: 851.3 req/s (1.2 ms/req)
Request size [B]: 83.0Reply rate [replies/s]: min 0.0 avg 0.0 max 0.0 stddev 0.0 (0 samples)
Reply time [ms]: response 0.6 transfer 0.6
Reply size [B]: header 278.0 content 42562.0 footer 0.0 (total 42840.0)
Reply status: 1xx=0 2xx=2000 3xx=0 4xx=0 5xx=0CPU time [s]: user 0.62 system 1.73 (user 26.2% system 73.7% total 99.9%)
Net I/O: 35683.0 KB/s (292.3*10^6 bps)Errors: total 0 client-timo 0 socket-timo 0 connrefused 0 connreset 0
Errors: fd-unavail 0 addrunavail 0 ftab-full 0 other 0
从以上数据可以看到 yo2cache 性能挺好的，最高能达到每秒 1500 个并发处理。性能瓶颈是出现在缓存数据的解压与压缩处理上，如果缓存空间足够大的话，可以考虑保存多种格式的缓存数据，就能解决这个瓶颈问题。
而在 deflate 数据压缩方面，因为2级压缩率与4级压缩率所产生的数据量差距不大，但并发性能有一定差距，可以考虑使用 2 级压缩率。
From：http://oneoo.com/articles/httperf-the-pressure-of-a-high-performance-test-tools.html
