Thanks Maynard!

It worked perfectly, now i get coherent results.

Cheers.

El martes 29 de mayo de 2012 a las 16:30, Maynard Johnson escribió:

On 05/28/2012 03:49 PM, Pedro Erencia wrote:
Hi everybody,

I'm using oprofile to profile an application, but i'm running through some issues i'd like to post here in case anyone can help me. The fact is that oprofile does not seem to give me correct reports

This is what i do

rm tmpfile; for i in `seq 3`; do opcontrol --shutdown; opcontrol --init; opcontrol --start ; opcontrol --reset; time ./blastp -query /home/perencia/Secuencias/tremblr/selected/1000_30 -db /home/perencia/Secuencias/swissprot -num_threads 2; opcontrol --stop; opreport >> tmpfile; done; cat tmpfile | grep blastp;


So the application that i'm running is blastp, a multithreaded application, in this case with 2 threads.
opcontrol --status gives me that

Daemon running: pid 11694
Event 0: CPU_CLK_UNHALTED:100000:0:1:1
Separate options: none
vmlinux file: none
Image filter: none
Call-graph depth: 6
Buffer size: 65536

So, after running the application in the loop i get this times from the time command..

real0m5.293s

user0m10.225s

sys0m0.056s


real0m5.277s

user0m10.117s

sys0m0.060s


real0m5.210s

user0m10.045s

sys0m0.056s


but oprofile reports this cycles


277513 93.6010 blastp

167677 90.9287 blastp

164675 91.5181 blastp


The machine has a 2.66 GHz processor, so the first result, (277513/2 threads) * 100000 / (2.66 * 10^9) = 5.21 seconds, seems accurate. But what about the other two ? Doing the calculations they report 3 seconds, not the 5 seconds reported by time.


Am i missing something ?
Try running with 'opcontrol --callgraph=0'. Collecting callgraph data can sometimes add too much overhead, causing oprofile to drop samples because it can't keep up with the amount of data. There's not enough info for me to say for sure that's happening, but it's a theory.

-Maynard


Cheers.









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