Re: [PATCH 2/4] ftrace - add function_duration tracer

[fche@redhat.com (Frank Ch. Eigler)]

Ingo Molnar <mingo@elte.hu> writes:

> [...]
> Just off the top of my head we want to be able to trace:
>
>  - max irq service latencies for a given IRQ
>  - max block IO completion latencies for a app
>  - max TLB flush latencies in the system
>  - max sys_open() latencies in a task
>  - max fork()/exit() latencies in a workload
>  - max scheduling latencies on a given CPU
>  - max page fault latencies
>  - max wakeup latencies for a given task
>  - max memory allocation latencies
>
>  - ... and dozens and dozens of other things where there's a "start"
>    and a "stop" event and where we want to measure the time between
>    them.
> [...]

FWIW, those who want to collect such measurements today can do so with
a few lines of systemtap script for each of the above.


- FChE