mem-ruby: add option to disable GPU coalescer deadlock watchdog - #4
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Basemism wants to merge 11 commits into
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mem-ruby: add option to disable GPU coalescer deadlock watchdog#4Basemism 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
The GPU coalescer watchdog aborts the simulation when a request stays outstanding longer than deadlock_threshold. This false-triggers in slow-memory sensitivity experiments where DRAM timings are intentionally stretched and long-lived requests are expected. Add a disable_deadlock_check parameter to GPUCoalescer (default False, so the watchdog stays on by default) and gate the wakeup() deadlock scan on it. Expose it through GPU_VIPER's --disable-watchdog flag, wired to both VIPER coalescers.
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Add a disable_deadlock_check parameter to GPUCoalescer and gate the deadlock scan in wakeup() on this parameter. It defaults to False, keeping current behaviours unchanged.
A --disable-watchdog option is also added to GPU_VIPER, disabling the deadlock check on both GPU VIPER coalescers. Other coalescer wakeup and request-processing behaviour remains unchanged.
This is useful when investigating pathological slowdowns in gem5. In some cases, execution may still be making forward progress but take significantly longer than the watchdog threshold. Panicking as soon as the threshold is reached might mask the underlying issue and preventing the simulation from running long enough to diagnose the source of the slowdown.
(In my case detecting the 1 GiB lookup issues)