[concurrency-interest] ConcurrentSkipListMap performance
mohanr at fss.co.in
Thu Nov 10 06:33:13 EST 2011
I found this a section on 'Compilation' in http://www.cs.princeton.edu/picasso/mats/HotspotOverview.pdf that has some details.
From: concurrency-interest-bounces at cs.oswego.edu [mailto:concurrency-interest-bounces at cs.oswego.edu] On Behalf Of Nathan Reynolds
Sent: Tuesday, October 25, 2011 9:46 PM
To: Thorsten Möller
Subject: Re: [concurrency-interest] ConcurrentSkipListMap performance
I turn on HotSpot's -XX:-PrintCompliation and run the warmup and test. If I see any messages during the actual test (after warmup), then I know I didn't warmup the JVM long enough.
The parameter -XX:CompileThreshold (i.e. optimizer threshold) defaults to 10,000 when using the "-server" flag. I find that if I run the method under test and all of the test harness code 11,000 times then I don't see any compiler (optimizer) messages during my test. I also put a Thread.sleep after warmup but before running the test. This gives time and CPU resources to the compiler (optimizer) threads.
Getting this right was very tricky. I am still not confident that I have mastered it yet. I should really do some harness tests to gain more confidence.
Nathan Reynolds <http://psr.us.oracle.com/wiki/index.php/User:Nathan_Reynolds> | Consulting Member of Technical Staff | 602.333.9091
Oracle PSR Engineering <http://psr.us.oracle.com/> | Server Technology
On 10/25/2011 2:13 AM, Thorsten Möller wrote:
Am 24.10.2011 um 22:20 schrieb Nathan Reynolds:
Note: HotSpot does have an optimizer logging feature and can be used to determine if the optimizer is finished (i.e. by lack of further output).
Interesting - wasn't aware of this yet. Could you detail how it can be used. Seems that it is a JVM parameter ?
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