RFR: 8196334: Optimize UUID#fromString
ivan.gerasimov at oracle.com
Fri Feb 28 23:58:40 UTC 2020
I think the current proposal is clearly a progress, so it looks good.
I agree that any further optimization can be considered within a
separate enhancement request.
With kind regards,
On 2/28/20 2:59 PM, Claes Redestad wrote:
> 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.
> 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
>> Then, you could operate directly on bytes and avoid dealing with longs.
>> With kind regards,
>> 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
With kind regards,
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