Hi Ivan,
I've considered trying it out, but it gets complicated as we don't want
to penalize -XX:-UseCompactStrings.
I think adding special methods for UUID inside StringLatin1 is a step
in the wrong direction, but maybe there's something more generic we can
consider. However, short of adding String.value()+coder() access via
JavaLangAccess I'm not sure there's anything that'd net us any
significant gain. And I don't think it's worth it to open up that
particular can of worms right now just for this.
/Claes
On 2020-02-28 20:51, Ivan Gerasimov wrote:
Hi Claes and Andriy!
It looks good overall.
I wonder if it'll be even faster if the fast path were implemented in
StringLatin1 (for compact strings only) and was called via
SharedSecrets/JavaLangAccess?
Then, you could operate directly on bytes and avoid dealing with longs.
With kind regards,
Ivan
On 2/28/20 6:22 AM, Claes Redestad wrote:
Hi all,
please review this patch to optimize UUID#fromString.
Jon Chambers originally proposed a patch that used a strict parser to
get a similar speed-up, but I failed to adapt it in a way that
could fall back to the less strict behavior while maintaining a
reasonable speed-up in the fast-path case. Sorry, Jon!
The patch proposed here was recently contributed by Andriy Plokhotnyuk
(OCA signed), and manages to get more than a 3x speed-up on the new
fromString microbenchmark, while falling back gently to the current,
less strict implementation if ever needed. I've done some light edits,
and added a simple microbenchmark.
Bug: https://bugs.openjdk.java.net/browse/JDK-8196334
Webrev: http://cr.openjdk.java.net/~redestad/8196334/open.00/
Testing: tier1-3
Thanks!
/Claes
