Re: [tlug] meaning of dprofpp output

[Simon Cozens <simon@example.com>]

Nguyen Vu Hung wrote:
> 1. What is the meaning of "Total Elapsed Time"?,
> Why Total Elapsed Time = 450 seconds which is not equal to
> sum of all ExclSec below?

You need to understand the difference between wallclock time and process
time. Wallclock time is how long a process actually runs for; process
time is the amount of CPU it got. Try looking at
http://docs.babitch.com/O'Reilly/unix/upt/ch39_05.htm

> 2. Can I conclude that sub routine REMOVED1 is the cause
> to the performance issue? It takes 7.3 seconds to be excuted.

Possibly, but it sounds like you're more concerned about the other 7
minutes than the 7 seconds. Is your code doing lots of network access on
slow sites? Calling out to dodgy database queries?

As for the 7 seconds taken up by REMOVED1, this may be because it has a
lot of work to do - this is normal for programs that do things; if you
have subroutines which don't take any time it's because they don't do
anything!

If it's hanging for 7 minutes, though, then you need to look at IO. I
would try stopping Apache, and running "strace apache -D" (or maybe
"strace httpd -D" depending on your distribution) and seeing what system
calls are being made that are stopping it. This will produce a lot of
output, but the only lines you're really interested in are the lines
around the time then it hangs for a noticable period.

-- 
<Twofish> Pokemon seems an evil concept. Kid hunts animals, and takes
them from the wild into captivity, where he trains them to fight, and
then fights them to the death against other people's pokemon. Doesn't
this remind you of say, cock fighting?