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From: Jon Harrop <jonathandeanharrop@googlemail.com>
To: "'Gerd Stolpmann'" <info@gerd-stolpmann.de>
Cc: <caml-list@inria.fr>
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Date: Sat, 16 Apr 2011 13:12:29 +0100
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Subject: RE: [Caml-list] Efficient OCaml multicore -- roadmap?

Gerd wrote:
> AFAIK TLS is not costless but relatively cheap.

Actually TLS is very expensive in this context because thread-local data is accessed so frequently. When I hoisted the use of TLS by carrying pointers to thread-local data around (altering the calling convention) in HLVM it resulted in 1.5-2x speedups on all benchmarks and the result was then only 17% slower than serial code.

Cheers,
Jon.