RFR: 8205051: UseNUMA memory interleaving vs cpunodebind & localalloc [v2]

Swati Sharma duke at openjdk.org
Tue Dec 3 06:26:15 UTC 2024


> Hi All,
> 
> The PR handles the performance issues related to flag UseNUMA. We disable the UseNUMA flag when the process gets invoked with incorrect node alignment.
> We check the cpunodebind and membind(or interleave for interleave policy) bitmask equality and disable UseNUMA when they are not equal.
> For example on a 4 NUMA node system:
> 0123 Node Number
> 1100  cpunodebind bitmask
> 1111 membind bitmask 
> Disable UseNUMA as CPU and memory bitmask are not equal.
> 
> 0123 Node Number  
> 1100  cpunodebind bitmask
> 1100 membind bitmask 
> Enable UseNUMA as CPU and memory bitmask are equal.
> 
> This covers all the cases with all policies and tested this with below command
> numactl --cpunodebind=0,1 --localalloc java -Xlog:gc*=info -XX:+UseParallelGC -XX:+UseNUMA -version
> 
> For localalloc and preferred policies the membind bitmask returns true for all nodes, hence if cpunodebind is not bound to all nodes then the UseNUMA will be disabled.
> 
> This PR covers disabling the UseNUMA flag for all GC's hence we observed an improvement of ~25% on G1GC , ~20% on ZGC and ~7-8% on PGC in both throughput  and latency on SPECjbb2015 on a 2 NUMA node SRF-SP system with 6Group configuration.
> 
> Please review and provide your valuable comments.
> 
> Thanks,
> Swati Sharma
> Intel

Swati Sharma has updated the pull request incrementally with one additional commit since the last revision:

  8205051: Resolved review comments.

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/22395/files
  - new: https://git.openjdk.org/jdk/pull/22395/files/6ce32a80..220e9519

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=22395&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=22395&range=00-01

  Stats: 41 lines in 2 files changed: 26 ins; 0 del; 15 mod
  Patch: https://git.openjdk.org/jdk/pull/22395.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22395/head:pull/22395

PR: https://git.openjdk.org/jdk/pull/22395


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