Re: [PerfSuite-users] Wall clock time ??

[Rui L. <ru...@nc...>]

Hi wkq,

Wall clock time = <wallclock ticks in the psrun-generated XML>/<CPU freq>

psrun uses libpshwpc's API functions ps_hwpc_start() and ps_hwpc_stop() to start and stop the counting or profiling, which in turn use libperfsuite's API function ps_rtc() to record the start and end ticks.  ps_hwpc_stop also writes the output file; the "wallclock" element in the output file contains the difference of the start and end ticks.  The ps_rtc() function samples a high resolution wallclock (real time) timer, which differs on each architecture/system.

Thanks,
Rui

On 02/08/2011 01:46 AM, 吴名 wrote:
> Hi Rui,
> I check the metric in the link
> http://perfsuite.ncsa.uiuc.edu/psprocess/metrics.shtml,
> the Wall clock time (seconds) is not there, I don't know  the exact
> meaning. since I run the command, CPU time equals
> cycles/cpu freq, and the total elpased time is not Wall clock
> time.(you can use gettimeofday to verify it). So  wall clock time
> meaning ? How does psrun get the value??
> 
> 
> Thanks.
> 
> wkq
>