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aco: Consider LDS usage by PS inputs in MaxWaves calculation.

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Before PS waves are launched, PS inputs are moved from PC to LDS
and the corresponding part of the PC is deallocated.
Each PS input occupies 3 * vec4 (3 * 16 = 48 bytes) of LDS space.
See Figure 10.3 in the GCN3 ISA manual.

These limit occupancy the same way as other stages' LDS usage does.
Note that PS can request additional LDS space via EXTRA_LDS_SIZE,
so that also must be taken into account here.

No Fossil DB changes.

Signed-off-by: Timur Kristóf <timur.kristof@gmail.com>
Reviewed-by: Daniel Schürmann <daniel@schuermann.dev>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/12517>
This commit is contained in:
Timur Kristóf 2021-08-24 08:44:54 +02:00 • committed by Marge Bot
parent 9bc61108d7
commit c8698199a1
1 changed files with 18 additions and 4 deletions
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22
src/amd/compiler/aco_live_var_analysis.cpp
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@ -375,11 +375,25 @@ update_vgpr_sgpr_demand(Program* program, const RegisterDemand new_demand)
/* adjust max_waves for workgroup and LDS limits */
unsigned waves_per_workgroup = calc_waves_per_workgroup(program);
unsigned workgroups_per_cu_wgp = max_waves_per_simd * simd_per_cu_wgp / waves_per_workgroup;
if (program->config->lds_size) {
unsigned lds = program->config->lds_size * program->dev.lds_encoding_granule;
lds = align(lds, program->dev.lds_alloc_granule);
workgroups_per_cu_wgp = std::min(workgroups_per_cu_wgp, lds_limit / lds);
unsigned lds_per_workgroup =
align(program->config->lds_size * program->dev.lds_encoding_granule,
program->dev.lds_alloc_granule);
if (program->stage == fragment_fs) {
/* PS inputs are moved from PC (parameter cache) to LDS before PS waves are launched.
* Each PS input occupies 3x vec4 of LDS space. See Figure 10.3 in GCN3 ISA manual.
* These limit occupancy the same way as other stages' LDS usage does.
*/
unsigned lds_bytes_per_interp = 3 * 16;
unsigned lds_param_bytes = lds_bytes_per_interp * program->info->ps.num_interp;
lds_per_workgroup +=
align(lds_param_bytes, program->dev.lds_alloc_granule);
}
if (lds_per_workgroup)
workgroups_per_cu_wgp = std::min(workgroups_per_cu_wgp, lds_limit / lds_per_workgroup);
if (waves_per_workgroup > 1 && program->chip_class < GFX10)
workgroups_per_cu_wgp = std::min(
workgroups_per_cu_wgp, 16u); /* TODO: is this a SI-only limit? what about Navi? */