[Intel-gfx] [PATCH igt 1/3] benchmark/gem_busy: Compare polling with syncobj_wait

[Tvrtko Ursulin]

On 28/09/2017 10:07, Chris Wilson wrote:
> Quoting Tvrtko Ursulin (2017-09-28 07:53:56)
>>
>> On 25/09/2017 21:26, Chris Wilson wrote:
>>> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>>> ---
>>>    benchmarks/gem_busy.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++-
>>>    1 file changed, 72 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/benchmarks/gem_busy.c b/benchmarks/gem_busy.c
>>> index f050454b..9649ea02 100644
>>> --- a/benchmarks/gem_busy.c
>>> +++ b/benchmarks/gem_busy.c
>>> @@ -58,6 +58,15 @@
>>>    #define DMABUF 0x4
>>>    #define WAIT 0x8
>>>    #define SYNC 0x10
>>> +#define SYNCOBJ 0x20
>>> +
>>> +#define LOCAL_I915_EXEC_FENCE_ARRAY (1 << 19)
>>> +struct local_gem_exec_fence {
>>> +     uint32_t handle;
>>> +     uint32_t flags;
>>> +#define LOCAL_EXEC_FENCE_WAIT (1 << 0)
>>> +#define LOCAL_EXEC_FENCE_SIGNAL (1 << 1)
>>> +};
>>>    
>>>    static void gem_busy(int fd, uint32_t handle)
>>>    {
>>> @@ -109,11 +118,54 @@ static int sync_merge(int fd1, int fd2)
>>>        return data.fence;
>>>    }
>>>    
>>> +static uint32_t __syncobj_create(int fd)
>>> +{
>>> +     struct local_syncobj_create {
>>> +             uint32_t handle, flags;
>>> +     } arg;
>>> +#define LOCAL_IOCTL_SYNCOBJ_CREATE        DRM_IOWR(0xBF, struct local_syncobj_create)
>>> +
>>> +     memset(&arg, 0, sizeof(arg));
>>> +     ioctl(fd, LOCAL_IOCTL_SYNCOBJ_CREATE, &arg);
>>> +
>>> +     return arg.handle;
>>> +}
>>> +
>>> +static uint32_t syncobj_create(int fd)
>>> +{
>>> +     uint32_t ret;
>>> +
>>> +     igt_assert_neq((ret = __syncobj_create(fd)), 0);
>>> +
>>> +     return ret;
>>> +}
>>> +
>>> +#define LOCAL_SYNCOBJ_WAIT_FLAGS_WAIT_ALL (1 << 0)
>>> +#define LOCAL_SYNCOBJ_WAIT_FLAGS_WAIT_FOR_SUBMIT (1 << 1)
>>> +struct local_syncobj_wait {
>>> +       __u64 handles;
>>> +       /* absolute timeout */
>>> +       __s64 timeout_nsec;
>>> +       __u32 count_handles;
>>> +       __u32 flags;
>>> +       __u32 first_signaled; /* only valid when not waiting all */
>>> +       __u32 pad;
>>> +};
>>> +#define LOCAL_IOCTL_SYNCOBJ_WAIT     DRM_IOWR(0xC3, struct local_syncobj_wait)
>>> +static int __syncobj_wait(int fd, struct local_syncobj_wait *args)
>>> +{
>>> +     int err = 0;
>>> +     if (drmIoctl(fd, LOCAL_IOCTL_SYNCOBJ_WAIT, args))
>>> +             err = -errno;
>>> +     return err;
>>> +}
>>> +
>>>    static int loop(unsigned ring, int reps, int ncpus, unsigned flags)
>>>    {
>>>        struct drm_i915_gem_execbuffer2 execbuf;
>>>        struct drm_i915_gem_exec_object2 obj[2];
>>>        struct drm_i915_gem_relocation_entry reloc[2];
>>> +     struct local_gem_exec_fence syncobj;
>>>        unsigned engines[16];
>>>        unsigned nengine;
>>>        uint32_t *batch;
>>> @@ -126,6 +178,11 @@ static int loop(unsigned ring, int reps, int ncpus, unsigned flags)
>>>        fd = drm_open_driver(DRIVER_INTEL);
>>>        gen = intel_gen(intel_get_drm_devid(fd));
>>>    
>>> +     if (flags & SYNCOBJ) {
>>> +             syncobj.handle = syncobj_create(fd);
>>> +             syncobj.flags = LOCAL_EXEC_FENCE_SIGNAL;
>>> +     }
>>> +
>>>        memset(obj, 0, sizeof(obj));
>>>        obj[0].handle = gem_create(fd, 4096);
>>>        if (flags & WRITE)
>>> @@ -144,6 +201,8 @@ static int loop(unsigned ring, int reps, int ncpus, unsigned flags)
>>>        execbuf.buffer_count = 2;
>>>        execbuf.flags |= LOCAL_I915_EXEC_HANDLE_LUT;
>>>        execbuf.flags |= LOCAL_I915_EXEC_NO_RELOC;
>>> +     if (flags & SYNCOBJ)
>>> +             execbuf.flags |= LOCAL_I915_EXEC_FENCE_ARRAY;
>>
>> According to the comment in i915_drm.h, when this is specified, syncobj
>> should be also passed in in cliprects_ptr but that's not happening?
> 
> You want -b support as well! :)

I just failed to figure out where is the connection between syncobj 
(local var) and execbuf. Flag is set, so what happens next? Execbuf 
fails since cliprects_ptr is not set?

Regards,

Tvrtko