Re: Cumulative samples without callgraph?
Nikolaus Rath <[email protected]>
| Newsgroups | gmane.linux.oprofile |
|---|---|
| Organization | Tri Alpha Energy |
| Message-ID | <[email protected]> |
On 05/12/2015 07:55 PM, William Cohen wrote: > On 04/16/2015 01:00 PM, Nikolaus Rath wrote: >> Hello, >> >> I have gathered some profile data using just "operf <program>" >> (i.e., no -g option to gather callgraph data). >> >> However, when looking at the gmon output with >> >> $ opgprof <program> $ gprof -p <program> | head >> >> I find that there are distinct counts for cumulative and self: >> >>> Flat profile: >>> >>> Each sample counts as 1 samples. % cumulative self >>> self total time samples samples calls T1/call >>> T1/call name 5.19 14089090.00 14089090.00 >>> dagmg_mumps_302_ 4.85 27256080.00 13166990.00 >>> mcdriver_mp_mc_push_ 4.83 40373868.00 13117788.00 >>> dagmg_mumps_249_ 4.56 52738720.00 12364852.00 >> >> >> I'm confused by this. Doesn't "cumulative" mean the time spend in >> a function including time spend in calls to other functions? But if >> operf didn't look at the callgraph, how can it know anything about >> this? I thought that for every sample operf just records what >> function is being executed, but not how this function was called. >> > > gprof is only providing the flat sample information. The cumulative > samples is the sum of all the samples up to that point. Thus, the > first line cumulative samples has 14089090.00, second line is > 14089090+13117788=27256080, the third line is > 14089090+13117788+13117788=40373868. Ah, thank you! So just to make sure: this cumulative count is thus not at all what "cumulative" means when the profiling data is generated by e.g. "gcc -pg", and it does not tell me anything about how much time was spent with a given function on the stack? Best, -Nikolaus ------------------------------------------------------------------------------ One dashboard for servers and applications across Physical-Virtual-Cloud Widest out-of-the-box monitoring support with 50+ applications Performance metrics, stats and reports that give you Actionable Insights Deep dive visibility with transaction tracing using APM Insight. http://ad.doubleclick.net/ddm/clk/290420510;117567292;y