Messages in this thread | | | From | Joel Fernandes <> | Date | Wed, 10 May 2017 16:04:55 -0700 | Subject | [RFC] adding of TGID to ftrace output |
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Hi Steven,
Can we add TGID information along with PID to ftrace output?
Something like: # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID:TGID CPU# |||| TIMESTAMP FUNCTION # | | | | |||| | | bash-1977:1977 [000] .... 17284.993652: sys_close <-
Instead of: # _-----=> irqs-off # / _----=> need-resched # | / _---=> hardirq/softirq # || / _--=> preempt-depth # ||| / delay # TASK-PID CPU# |||| TIMESTAMP FUNCTION # | | | |||| | | bash-1977 [000] .... 17284.993652: sys_close <-
Currently in android, we inject tgid into each trace event at the end of the trace just so we can group threads under a process in our trace viewer.
The other option we're thinking off is we can retrieve tgid during the trace output (reading trace file from debugfs/tracefs) from the task_struct and then have ftrace output it that way.
Anyway, having this will really simplify things and make it more reliable (we run ps -T at the end of the trace right now, but its unreliable because threads might have exited by then). We also have to call getpid() and inject pid into each userspace trace_marker write just so we can do this grouping.
Regards, Joel
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