[igt-dev] [PATCH i-g-t 5/6] tests/i915/gem_exec_schedule: Avoid cmdparser dependencies in deep()

[Daniel Vetter]

On Sat, Jul 10, 2021 at 10:52:03PM -0500, Jason Ekstrand wrote:
> When we have a command parser which runs synchronously, it blocks until
> the batch is idle.  For most userspace, this doesn't matter as they
> never re-use a batch.  With IGT, this can be a problem because it means
> we can't queue up multiple instances of the same batch.  The easy
> solution is to create a new batch BO for each execbuf.
> 
> Signed-off-by: Jason Ekstrand <jason at jlekstrand.net>

I'm way behind on all the reloc work I've done, but should we instead do
my patch (which you reviewed):

https://patchwork.freedesktop.org/patch/437683/

Or does that not work? Asking since you're papering over the same issue I
spotted already ...
-Daniel

> ---
>  tests/i915/gem_exec_schedule.c | 10 +++++++---
>  1 file changed, 7 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/i915/gem_exec_schedule.c b/tests/i915/gem_exec_schedule.c
> index a75faeb68..ee7b10f7f 100644
> --- a/tests/i915/gem_exec_schedule.c
> +++ b/tests/i915/gem_exec_schedule.c
> @@ -1891,7 +1891,6 @@ static void deep(int fd, const intel_ctx_cfg_t *cfg,
>  		reloc.delta = sizeof(uint32_t) * n;
>  		reloc.read_domains = I915_GEM_DOMAIN_RENDER;
>  		reloc.write_domain = I915_GEM_DOMAIN_RENDER;
> -		obj[2].handle = gem_create(fd, 4096);
>  		obj[2].relocs_ptr = to_user_pointer(&reloc);
>  		obj[2].relocation_count = 1;
>  
> @@ -1910,15 +1909,20 @@ static void deep(int fd, const intel_ctx_cfg_t *cfg,
>  		}
>  		batch[++i] = eb.rsvd1;
>  		batch[++i] = MI_BATCH_BUFFER_END;
> -		gem_write(fd, obj[2].handle, 0, batch, sizeof(batch));
>  
>  		gem_context_set_priority(fd, eb.rsvd1, MAX_PRIO - nreq + n);
>  		for (int m = 0; m < XS; m++) {
>  			obj[1].handle = dep[m];
>  			reloc.target_handle = obj[1].handle;
> +
> +			/* Create a new batch BO every time so we don't end
> +			 * up with extra dependencies
> +			 */
> +			obj[2].handle = gem_create(fd, 4096);
> +			gem_write(fd, obj[2].handle, 0, batch, sizeof(batch));
>  			gem_execbuf(fd, &eb);
> +			gem_close(fd, obj[2].handle);
>  		}
> -		gem_close(fd, obj[2].handle);
>  	}
>  	igt_info("First deptree: %d requests [%.3fs]\n",
>  		 n * XS, 1e-9*igt_nsec_elapsed(&tv));
> -- 
> 2.31.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch