[RFC] Scheduler recorder and playback

[Pantelis Antoniou]

Hi Dmitry,

There is big difference between threads and processes as far as the kernel
is concerned; both are performed by just a clone syscall, and share or 
not address space/fd's etc.

If you want to replay per-process workloads, you can just
record only the activity of the pids of the threads of the process.

In the future I will try to record thread creation but I'm not sure
if the current tracepoints allow to differentiate between a fork
or a thread creation; a new tracepoint might be needed which I explicitly
wanted to avoid.

Regards

-- Pantelis

On Apr 4, 2012, at 12:57 PM, Dmitry Antipov wrote:

> On 04/02/2012 02:15 PM, Pantelis Antoniou wrote:
> 
>>> Example session:
>>> 
>>> # perf sched record
>>> 
>>> <  run process, etc.>
>>> 
>>> ^C<- perf ends producing a perf.data file.
>>> 
>>> # perf sched spr-replay -l
>>> <lists tasks and pids in the trace>
>>> 
>>> # perf sched spr-replay -s<pid#1>  -s<name>  -d -n -g
>>> <see the trace program for the processes with pid#1 and named<name>
>>> 
>>> # perf sched spr-replay -s<pid#1>  -g>test.spr
>>> <generates test.spr which contains the program of pid#1>
>>> 
>>> # perf sched spr-replay -f test.spr -d
>>> <execute the test.spr program>
> 
> Do you have any thoughts on how to replay multithreaded workloads?
> We definitely wants to replay per-process, not per-thread workloads.
> 
> Dmitry
> 
>