[ltt-dev] LTTV Enhancement

Pierre-Marc Fournier pierre-marc.fournier at polymtl.ca
Sun Nov 22 14:33:57 EST 2009

Mathieu Desnoyers wrote:
> * Chris Smowton (cs448 at cam.ac.uk) wrote:
>> Hey,
>> Here's a slightly more constructive patch: this one adds support in
>> LTTV's generic state monitoring code and its control flow visualiser to
>> note when a process is woken by another process using the
>> sched_try_wakeup event.
>> Previously the woken process would continue to register its old state
>> until such time as it got scheduled; here the process transitions to
>> WAIT_CPU state (like preempted processes, indicating it is ready to run
>> but not currently scheduled). Ordinarily we see this state exist very
>> briefly, in between the device driver IRQ (typically) clearing it to run
>> and the scheduler invocation after irq_exit, but on a heavily loaded
>> system we might see a large stripe of dark yellow indicating the process
>> is ready but cannot yet be allocated a core.
> This is indeed the right thing to do ! :) Thanks very much for the
> patch.
> I'll wait for feedback from Pierre-Marc, who maintains the resource
> view, to see if this view too need to be updated. When I get his OK,
> I'll pull your patch.

This looks like an excellent idea. You have my OK.


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