When I ran a program on the Pgroup profilerthe largest amout of time was system time. In my case on the basis of time it made uo 67% of the time. What does this mean and how can I reduce it? It seems that it wiould be impossible to reduce system time.
Thanks in advance.
THX 1138
Hi THX 1138,
System time is the time spent executing code other than what is part of your host program. So calls to your OS libraries like malloc, sleep, open, etc., would be put here. Also, if you are running GPU programs, the time spent running of the device and copying data would be put there as well.
What you need to do is determine where the system time is coming from using a profiler. Only then can you tell if/how to reduce it.
Okay, how do I do that? How I do I tell if thw system time is coming from the from using the profiler?
Also, sometimes the system times does not show up in the output. Sometimes, only the functions of my program show up in the output… So what did I do to get the system time put in, or what did I do to get rid it it in the output?
Thanks in advance.
THx 1138
Hi THX 1138,
For information on using the PGI Profiler, please seehttp://www.pgroup.com/doc/pgprofug.pdf.
How I do I tell if thw system time is coming from the from using the profiler?
Note that I want you to profile the code to see where the system time is coming from, not that the system time is coming from using the profiler.
Also, sometimes the system times does not show up in the output. Sometimes, only the functions of my program show up in the output… So what did I do to get the system time put in, or what did I do to get rid it it in the output?
Instead of using the “-Mprof” flags to instrument your code, use the “pgcollect” utility. While pgcollect is sample based so not as accurate, it does profile the entire program including system routines. “-Mprof” only instruments user code.
I was using pgcollect. I know there are other ways to profile, but I used
pgcollect ./prog
and the results is what I said before.
Thanks in advance.
Newport_j