[users@httpd] httpd usage differences using "ab" and "httperf"

["Rose, John B" <jb...@utk.edu>]

Red Hat 7, Apache 2.4.6, 48 GB RAM, 16 cores

We have been doing some testing us both "ab" and "httperf" sending what we think are the same parameters. The # of processes and RAM usage look pretty much the same, but cpu usage is vastly different. Using "ab" seems to use a total average of 71% of cpu resources. Using "httperf" looks to use 4.7% of total cpu resources. Also, the cpu% for each httpd process is pretty different.

Using "top" to analyze both ...

1. Command: ab -t 500 -n 300000 -c 300 ourserver.com

Selected "top" output

%Cpu(s): 71.0 us

 PID       USER      PR  NI    VIRT    RES        SHR S  %CPU %MEM     TIME+ COMMAND
10407 apache    20   0  415332  10064   3752 R  42.8  0.0   0:02.16 httpd

2.  Command: httperf --hog -server ourserver.com --num-conn 300000 --ra 300

Selected "top" output

%Cpu(s):  4.7 us,

 PID       USER      PR  NI    VIRT    RES        SHR S  %CPU %MEM     TIME+ COMMAND
10625 apache    20   0  415308  10060   3756 S  12.0  0.0   0:04.39 httpd


My questions are why are they so different, and which one most accurately reflects real traffic?

Thanks

Re: [users@httpd] httpd usage differences using "ab" and "httperf"

[Eric Covener <co...@gmail.com>]

On Mon, Dec 15, 2014 at 1:08 PM, Rose, John B <jb...@utk.edu> wrote:
> My questions are why are they so different, and which one most accurately
> reflects real traffic?


Maybe httperf defaults to using keepalive?  ab doesn't (-k).


-- 
Eric Covener
covener@gmail.com

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