llvm dev - Jun 2018 - Update thin-lto cache file atimes when on windows

Hi all,

After experimenting with thin-lto caching behaviour I found an issue with
pruning when on Windows.

Thin-lto cache file atimes are used for expiration based pruning, and since
Vista, access file times are not updated by Windows by default:
https://blogs.technet.microsoft.com/filecab/2006/11/07/
disabling-last-access-time-in-windows-vista-to-improve-ntfs-performance/

This means on Windows, cache files are currently being pruned from creation
time.

I've made a patch for this so any feedback would be appreciated:

D47266

Thanks,

Owen
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+pcc for LTO caching and +inglorion for Windows specific issues.
Teresa

On Fri, Jun 1, 2018 at 8:47 AM Owen Reynolds via llvm-dev <
llvm-dev at lists.llvm.org> wrote:
> Hi all,
>
> After experimenting with thin-lto caching behaviour I found an issue with
> pruning when on Windows.
>
> Thin-lto cache file atimes are used for expiration based pruning, and
> since Vista, access file times are not updated by Windows by default:
>
>
https://blogs.technet.microsoft.com/filecab/2006/11/07/disabling-last-access-time-in-windows-vista-to-improve-ntfs-performance/
>
> This means on Windows, cache files are currently being pruned from
> creation time.
>
> I've made a patch for this so any feedback would be appreciated:
>
> D47266
>
> Thanks,
>
> Owen
> _______________________________________________
> LLVM Developers mailing list
> llvm-dev at lists.llvm.org
> http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev
>

-- 
Teresa Johnson |  Software Engineer |  tejohnson at google.com |  408-460-2413
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