What does AggressiveOpts do with my timings?
Steve.Goldman at Sun.COM
Mon Mar 31 05:54:43 PDT 2008
Regina Anger wrote:
> Hi Steve,
>> This is likely a bug in the time caching feature introduced in b12 under
>> AggressiveOpts. You can confirm this by running with
>> "-XX:+AggressiveOpts -XX:-CacheTimeMillis" and see if the problem goes
>> away. There is an interaction between time caching, counted loops with
>> the server compiler, and biased locking, that can make time offsets go
>> squirrelly around 4 seconds (or BiasedLockingStartupDelay) into the
>> run. It should go away around b26, when time caching will be removed.
> Of course you were right, disabling time caching gave me stable results.
> Sad that timecaching seems to not work out as expected, I for myself also had scalability problems in some code which did a lot of System.currTimeMillis() in a lock ;)
> PS: Your blog is really interesting - both the airplane and of course also the compiler stuff. Thanks for writing those interesting articles.
:-) Too many Steve's. The Steve that answered you was Steve Bohne and
his blog is at http://blogs.sun.com/sbohne/ and afaik there isn't any
airplane and compiler stuff there though it is still interesting. My
blog http://blogs.sun.com/fatcatair does however does have compiler and
airplane stuff although it has been idle for a few months. Every Monday
I swear I'll add something in the coming week only to see Friday roll
around and I've never gotten to it. I don't know how the people that
blog every day do it.
Steve Goldman (aka fatcatair)
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