[PATCH] D122974: prevent ConstString from calling djbHash() more than once

Fri Apr 29 15:57:20 PDT 2022

llunak added a comment.

In D122974#3483203 <https://reviews.llvm.org/D122974#3483203>, @clayborg wrote:

> If the string pool caches the hash value, we could actually write out the hash in the cache file to speed up loading.

The patch doing that is D124704 <https://reviews.llvm.org/D124704> (except for the string pool caching).

> I didn't want to re-hash every string when I saved the strings out to the cache file due to the cost, but it would be interesting to look into to see if it improves performance.

I can measure 10% startup time saved when everything is already cached. Funnily enough, profiler consistently claims that saving caches got faster too (I already use D122975 <https://reviews.llvm.org/D122975>).

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D122974/new/

https://reviews.llvm.org/D122974