[igt-dev] [PATCH i-g-t 10/16] i915/gem_exec_whisper: Fork all-engine tests one-per-engine

[Chris Wilson]

Quoting Tvrtko Ursulin (2019-05-14 13:57:26)
> 
> On 08/05/2019 11:09, Chris Wilson wrote:
> > Add a new mode for some more stress, submit the all-engines tests
> > simultaneously, a stream per engine.
> > 
> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> > ---
> >   tests/i915/gem_exec_whisper.c | 27 ++++++++++++++++++++++-----
> >   1 file changed, 22 insertions(+), 5 deletions(-)
> > 
> > diff --git a/tests/i915/gem_exec_whisper.c b/tests/i915/gem_exec_whisper.c
> > index d3e0b0ba2..d5afc8119 100644
> > --- a/tests/i915/gem_exec_whisper.c
> > +++ b/tests/i915/gem_exec_whisper.c
> > @@ -88,6 +88,7 @@ static void verify_reloc(int fd, uint32_t handle,
> >   #define SYNC 0x40
> >   #define PRIORITY 0x80
> >   #define QUEUES 0x100
> > +#define ALL 0x200
> >   
> >   struct hang {
> >       struct drm_i915_gem_exec_object2 obj;
> > @@ -199,6 +200,7 @@ static void whisper(int fd, unsigned engine, unsigned flags)
> >       uint64_t old_offset;
> >       int i, n, loc;
> >       int debugfs;
> > +     int nchild;
> >   
> >       if (flags & PRIORITY) {
> >               igt_require(gem_scheduler_enabled(fd));
> > @@ -215,6 +217,7 @@ static void whisper(int fd, unsigned engine, unsigned flags)
> >                               engines[nengine++] = engine;
> >               }
> >       } else {
> > +             igt_assert(!(flags & ALL));
> >               igt_require(gem_has_ring(fd, engine));
> >               igt_require(gem_can_store_dword(fd, engine));
> >               engines[nengine++] = engine;
> > @@ -233,11 +236,22 @@ static void whisper(int fd, unsigned engine, unsigned flags)
> >       if (flags & HANG)
> >               init_hang(&hang);
> >   
> > +     nchild = 1;
> > +     if (flags & FORKED)
> > +             nchild *= sysconf(_SC_NPROCESSORS_ONLN);
> > +     if (flags & ALL)
> > +             nchild *= nengine;
> > +
> >       intel_detect_and_clear_missed_interrupts(fd);
> >       gpu_power_read(&power, &sample[0]);
> > -     igt_fork(child, flags & FORKED ? sysconf(_SC_NPROCESSORS_ONLN) : 1)  {
> > +     igt_fork(child, nchild) {
> >               unsigned int pass;
> >   
> > +             if (flags & ALL) {
> > +                     engines[0] = engines[child % nengine];
> 
> Relying on PIDs being sequential feels fragile but suggesting pipes or 
> shared memory would be overkill. How about another loop:

Where are you getting pid_t from? child is an integer [0, nchild).
-Chris