prov/shm: make smr buffer pool allocations cache line aligned #11432
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Fixed the smr buffer pool alignment to match cache line size on x86 and aarch64 cpus. This has improved the p99 latencies and also throughput for nccl collective tests. Signed-off-by: Sunita Nadampalli <[email protected]>
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@snadampal Can you share some benchmarks and numbers your ran? |
aingerson
reviewed
Sep 23, 2025
| /* | ||
| * Set alignment to aarch64 and x86 cache line size. | ||
| */ | ||
| #define SHM_SMR_BUFPOOL_ALIGNMENT (64) |
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@aingerson thanks for the prompt review. I'm running some internal benchmarks, will try to collect data that I can share here.
remove shm prefix
:) I started with SMR_BUFPOOL_ALIGNMENT name and in the last minute I've added SHM prefix to make it provider specific. sure, I will remove the prefix it to match the other definitions related to smr.
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@snadampal SMR is the prefix for the shm provider. It is used instead of SHM to avoid any potential conflict with UNIX/Linux IPC "shm".
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Fixed the smr buffer pool alignment to match cache line size on x86 and aarch64 cpus. This has improved the p99 latencies and also throughput for nccl collective tests.