Re: [PATCH] mmap implementation for mingw.

From: Johannes Sixt <j.sixt@viscovery.net>
Date: Nov 21, 2008, 09:44 UTC
Message-ID: <492682E9.3030302@viscovery.net>
In-Reply-To: <gg5t5s$qc8$1@ger.gmane.org>

Please "reply to all" to keep the Cc list.

Vasyl' Vavrychuk schrieb:

>> Did you notice any differences with this? Or is this change just
>> because-we-can?
> Not yet.

This patch makes sense only if there is a noticable speed improvement. I doubt that the gain is measurable in the warm-cache case, but in the cold-cache case we can perhaps indeed save a number of disk accesses if whole pack files need not be slurped in (which the current mmap replacements do).

> Maybe write own getpagesize() based on GetSystemInfo()?

It's probably worth it (but only if mmap() makes sense at all). getpagesize() is used in the "sliding window" code to access pack files, and then the offset is non-zero and must be aligned properly. Make this a separate commit.

-- Hannes