Re: segfault runninng fio against 2048 jobs

[Jens Axboe <axboe@kernel.dk>]

On 04/18/2012 09:46 PM, Roger Sibert wrote:
> I verified the patch in fio-2.0.7-11-g7907 and that does indeed look to
> take care of the issue.  (Many thanks for that)
> 
> Also in follow up I changed the max job limit to 5120 and it seems to
> run properly against that as well.
> 
> Question though, is there any reason you have a REAL_MAX_JOBS in fio.h
> and then a FIO_MAX_JOBS in os.h.  First glance at it just shows that the
> init.c code uses FIO_MAX_JOBS in for the thread check and then later on
> it uses REAL_MAX_JOBS for the job check except that max_jobs is set
> equal to FIO_MAX_JOBS.  It may be that the answer to my question is the
> os-mac.h file which means you have a smaller thread count ... maybe then
> the result is just a small adjustment in the error print to show you
> have exceeded the max # of jobs and or max # of threads.

OSX has a seriously small max segment by default, hence the split and
smaller value there.

I should probably make the thread_data array be segmented, so that fio
could support an arbitrary number of jobs regardless of the max shm
segment size. So far it hasn't been a huge problem.

-- 
Jens Axboe