configs: model the GPU scalar cache separately from the SQC - #3
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Basemism wants to merge 11 commits into
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configs: model the GPU scalar cache separately from the SQC#3Basemism wants to merge 11 commits into
Basemism wants to merge 11 commits into
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This commit fixes the instruction execution latency of LDS instructions based on what microbenchmarks suggest
The LDS uses 4 byte wide banks in most GPUs. This requires each 4B address to map to a bank. The previous model mapped each byte to a bank and introduced several bank conflicts. This commit fixes the bank mapping to map each 4B word to an LDS bank Change-Id: Iaca0bcd3525a31c4ae55e379bf341a1de3ef8b31
Change-Id: I6dc1c9118027434a9e0bd26cc3843d3f56d955ad
Previously, the LDS model assumed each instruction has the same bus data transfer costs. This commit updates that to use the instruction dword length instead Change-Id: Id3decd6bb6fba3c50c84377ac5c7550660113092
Previously, `GlobalMemPipeline::getNextReadyResp` only checked the absolute oldest request in the entire ComputeUnit. If this single request was incomplete, it blocked all subsequent completed requests from being processed, degrading global memory pipeline performance. This commit updates the response selection logic to pick the oldest completed request on a per-wavefront basis. This prevents a single stalled wavefront from starving the entire CU, improving overall global memory pipeline throughput. Change-Id: Ia9bfde40a1940f450aee181ab816cc47dc677644
Introduce separate fabric_clk and memory_clk for the GPUFS, replacing the single ruby_clock domain. Change-Id: I817ab2e5a215b76728fd31dcc067535fd6590126
Previously, gpu clock was not applied to the model Change-Id: Ic3e39f984bc79fc0787282bb73d004a1f474e904
Create a distinct scalar-cache object and controller instead of reusing the SQC cache configuration for scalar memory requests. Add independent size and associativity options while continuing to share the SQC Ruby machine type and controller-version namespace required by GPU_VIPER. Keep existing defaults and route scalar sequencers through the new cache without enabling vector-data requests.
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🟢 Approval recommended
The changes are localized to configuration code and appear consistent with the stated goal while preserving defaults, with only minor maintainability feedback.
Pull request overview
This PR updates the GPU_VIPER Ruby configuration to model GPU scalar memory requests with a dedicated scalar L1 cache/controller instead of reusing the existing SQC cache configuration, while preserving existing default behavior.
Changes:
- Adds
ScalarCacheandScalarCntrlto provide a distinct cache object/controller for scalar requests. - Introduces
--scalar-sizeand--scalar-assocCLI options to tune the scalar cache independently. - Routes scalar sequencers through the new scalar cache/controller while keeping scalar requests on the existing SQC machine type/versioning namespace.
File summaries
| File | Description |
|---|---|
| configs/ruby/GPU_VIPER.py | Introduces dedicated scalar cache/controller classes, adds scalar cache sizing options, and switches scalar controller construction to use the new controller. |
Review details
- Files reviewed: 1/1 changed files
- Comments generated: 1
- Review effort level: Lite
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| class ScalarCache(RubyCache): | ||
| dataArrayBanks = 8 | ||
| tagArrayBanks = 8 | ||
| dataAccessLatency = 1 | ||
| tagAccessLatency = 1 | ||
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| def create(self, options): | ||
| self.size = MemorySize(options.scalar_size) | ||
| self.assoc = options.scalar_assoc | ||
| if hasattr(options, "sqc_rp"): | ||
| self.replacement_policy = ObjectList.rp_list.get(options.sqc_rp)() | ||
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Create a distinct scalar-cache object and controller instead of reusing the SQC cache configuration for scalar memory requests.
Add size and associativity options while continuing to share the SQC Ruby machine type and controller-version namespace.
Keep existing defaults and route scalar sequencers through the new cache without enabling vector-data requests.