Startup improvements #639
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Startup improvements #639
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The pool will result in power of 2 allocations as it doesn't have a local state when it is initially set up. This commit passes this extra space to the constructor of the pooled type, so that it can be feed into the freshly created allocator.
nwf-msr
reviewed
Sep 27, 2023
nwf-msr
reviewed
Sep 27, 2023
nwf-msr
reviewed
Sep 27, 2023
Co-authored-by: Nathaniel Wesley Filardo <nfilardo@microsoft.com>
nwf-msr
reviewed
Sep 28, 2023
nwf-msr
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Sep 28, 2023
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This PR improves the startup cost of snmalloc.
It adds a benchmark for profiling startup by starting a lot of threads, waiting for them to reach a stable point, each perform a single allocation deallocation pair, and terminate. It measure the time taken from all threads starting allocation until the last one has completed its deallocation.
The second commit makes the Pool pass the
sparememory in a meta-data allocation to the constructor of that type. This is then used to seed the local state in the backend with a small amount of meta-data, and means the first allocation does not need to request more meta-data memory.The benchmark goes from taking ~2.5M cycles to ~1.3M cycles for the checked build, and ~1.4M cycles to ~1.1M cycles for the fast build (wall clock cycles).