RFR: 8246338: Reduce overhead of normalizing file paths

[Alan Bateman]

On 02/06/2020 14:56, Claes Redestad wrote:
> Hi,
>
> this patch simplifies and improves performance of
> UnixFileSystem.normalize and prefixLength, which are used when opening
> files. The Windows implementation is left untouched, since it's a bit
> more complicated.
>
> Bug:    https://bugs.openjdk.java.net/browse/JDK-8246338
> Webrev: http://cr.openjdk.java.net/~redestad/8246338/open.00/
>
> On the provided microbenchmark, we see a small (5-10%) speed-up
> in peak performance, while the speed-up is quite large when
> interpreting, especially in the case where the file path is already
> normalized (2.1x)[1]. Since this is the normal case, the patch has a
> small but measurable effect on some startup tests.
I think this looks good.

-Alan.