Tick to sec conversion

From: Nikita Andreev (lestat_at_kemsu.ru)
Date: Fri Feb 26 2010 - 07:14:31 PST

  • Next message: Paul H. Hargrove: "Re: Tick to sec conversion"
    I want to clarify one thing. I need to collect tracing data from parallel application's threads and I use bupc_ticks_now call to do that. Documentation says:
    " It's important to keep in mind that raw bupc_tick_t values are thread-specific quantities with a thread-specific interpretation (e.g. they might represent a hardware cycle count on a particular CPU, starting at some arbitrary time in the past). ... Therefore as a rule of thumb, raw bupc_tick_t values and bupc_tick_t intervals obtained by different threads should never be directly compared or arithmetically combined, without first converting the relevant tick intervals to wall time intervals. "
    So am I understanding correctly that if I'm going to merge all trace files on one node then I need to write timestamps to trace files in seconds using bupc_ticks_to_ns? Apparently if I would try to convert tick to sec on node different form those at which it was collected I could get weird results, could I?

  • Next message: Paul H. Hargrove: "Re: Tick to sec conversion"