On Sun, Nov 11, 2018 at 8:46 PM Karol Herbst <[email protected]> wrote:
> an) > On Mon, Nov 12, 2018 at 12:37 AM Jason Ekstrand <[email protected]> > wrote: > > > > On November 11, 2018 16:36:16 Karol Herbst <[email protected]> wrote: > > > > > On Sun, Nov 11, 2018 at 10:48 PM Jason Ekstrand <[email protected]> > wrote: > > >> > > >> On Sun, Nov 11, 2018 at 3:35 PM Plamena Manolova > > >> <[email protected]> wrote: > > >>> > > >>> > > >>> Lowering shader variables which depend on the local work group > > >>> size being available in nir_lower_system_values is only possible > > >>> if the local work group size isn't variable, otherwise this should > > >>> be handled by the native driver (if it supports > > >>> ARB_compute_variable_group_size). > > >>> > > >>> > > >>> Signed-off-by: Plamena Manolova <[email protected]> > > >>> --- > > >>> src/compiler/nir/nir_lower_system_values.c | 22 > ++++++++++++++++++++++ > > >>> 1 file changed, 22 insertions(+) > > >>> > > >>> > > >>> diff --git a/src/compiler/nir/nir_lower_system_values.c > > >>> b/src/compiler/nir/nir_lower_system_values.c > > >>> index bde7eb1180..6fdf9f9c51 100644 > > >>> --- a/src/compiler/nir/nir_lower_system_values.c > > >>> +++ b/src/compiler/nir/nir_lower_system_values.c > > >>> @@ -77,6 +77,15 @@ convert_block(nir_block *block, nir_builder *b) > > >>> * "The value of gl_GlobalInvocationID is equal to > > >>> * gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID" > > >>> */ > > >>> + > > >>> + /* > > >>> + * If the local work group size is variable we can't lower > the global > > >>> + * invocation id here. > > >> > > >> > > >> Why not? > > >> > > >>> > > >>> > > >>> + */ > > >>> + if (b->shader->info.cs.local_size_variable) { > > >> > > >> > > >> I didn't realize we'd added a bit for this. At one point in time, > Karol > > >> had patches which had it keyed off of the size being zero. Having a > > >> separate bit is probably fine, it just surpised me. > > > > > > > > > yeah.. I guess I choose that, because I had nothing better. But I > > > guess having the size being 0 is good enough as long as we sure it is > > > 0 in relevant cases. > > > > It's fine. I just thought we'd chosen a different convention bit there's > > nothing wrong with it. I was just surprised. That's all. > > > > > > > >>> > > >>> > > >>> + break; > > >>> + } > > >>> + > > >>> nir_ssa_def *group_size = build_local_group_size(b); > > >>> nir_ssa_def *group_id = nir_load_work_group_id(b); > > >>> nir_ssa_def *local_id = nir_load_local_invocation_id(b); > > >>> @@ -115,6 +124,11 @@ convert_block(nir_block *block, nir_builder *b) > > >>> } > > >>> > > >>> > > >>> case SYSTEM_VALUE_LOCAL_GROUP_SIZE: { > > >>> + /* If the local work group size is variable we can't lower > it here */ > > >>> + if (b->shader->info.cs.local_size_variable) { > > >>> + break; > > >>> + } > > >>> + > > >>> sysval = build_local_group_size(b); > > >>> break; > > >>> } > > >>> @@ -189,6 +203,14 @@ convert_block(nir_block *block, nir_builder *b) > > >>> break; > > >>> > > >>> > > >>> case SYSTEM_VALUE_GLOBAL_GROUP_SIZE: { > > >>> + /* > > >>> + * If the local work group size is variable we can't lower > the global > > >>> + * group size here. > > >>> + */ > > >>> + if (b->shader->info.cs.local_size_variable) { > > >>> + break; > > >>> + } > > >> > > >> > > >> Why can't we lower the global size? It seems like we would want the > below > > >> multiplication regardless of whether the local size is constant. > > > > > > well I am not sure about ARB_compute_variable_group_size, but at least > > > in CL you know nothing about it at compile time as you specify > > > everything when you enqueue the kernel. Could be that the number of > > > work_groups is fixed with ARB_compute_variable_group_size though > > > > Why can't you multiply two non-constant things together? Maybe the driver > > can do something now efficient but it's not clear to me that this isn't > > what we want. > > > > oh, you meant it that way. Mhh, I actually wrote the patch adding > build_local_group_size to handle that inside that function (lower to > constants if known, intrinsics otherwise) as we need the local_size > for three different system values. I have a patch for that for CL, but > the patch itself is a bit hacky right now (as in, it doesn't handle it > inside build_local_group_size). > > And I think that patch misses handling for > SYSTEM_VALUE_GLOBAL_GROUP_SIZE anyhow. > > For CL we even want to add a global_invocation_id_offset system value > and add it when handling SYSTEM_VALUE_GLOBAL_INVOCATION_ID, but that > we can ignore for now. > > Anyhow, I think it would make sense to move the check into > build_local_group_sized and either return a constant value or an > intrinsic loading the value from the driver. I just remember vaguely > that I think somebody brought that up months ago and there was a good > reason not to do that for every driver? > That's what I was thinking. We don't want to lower load_local_group_size but then we want build_local_group_size to either build a constant or a load_local_group_size intrinsic as you said above. --Jason > > > > > >>> > > >>> > > >>> + > > >>> nir_ssa_def *group_size = build_local_group_size(b); > > >>> nir_ssa_def *num_work_groups = nir_load_num_work_groups(b); > > >>> sysval = nir_imul(b, group_size, num_work_groups); > > >>> -- > > >>> 2.11.0 > > >>> > > >>> > > >>> _______________________________________________ > > >>> mesa-dev mailing list > > >>> [email protected] > > >>> https://lists.freedesktop.org/mailman/listinfo/mesa-dev > > > > > > >
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