PERF
http://blog.csdn.net/zhangskd/article/details/37902159
perf record -F 99 -p PID -g — sleep 10
perf script | ./stackcollapse-perf.pl > out.perf-folded
flame graph
./flamegraph.pl out.perf-folded>ou.svg
wrk
https://github.com/wg/wrk
git clone https://github.com/wg/wrk.git
cd wrk/
make -j8
wrk -t12 -c400 -d30s http://127.0.0.1:8080/index.html
ab
http://httpd.apache.org/docs/2.4/
http://httpd.apache.org/docs/2.4/programs/ab.html
