On 5/5/15 3:53 PM, Rabin Vincent wrote:
The commands above will identify the sys_write which takes time but only provide the stacktrace at the entry and exit of the syscall, but this do not show why the process blocked or what it did inside the system call.So a way to get what is required for the use case would be to make the following changes to the above sequence: (1) include the sched:* events when perf trace record is run (2) around the time of interest, look at the kernel stack st the sched:switch events between the entry and the exit. This will show what the process was waiting for when it when it blocked. The stacktraces at the stat_runtime events in the process may also be useful to understand what was going on.
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