Hi Ivan; This looks like a good improvement. My only disappointment is that I didn't notice it when adding the roundUpToPowerOf2 method!
Do you need a sponsor to push the fix? Mike On Jul 30 2013, at 08:35 , Ivan Gerasimov wrote: > Hello everybody! > > HashTable needs to calculate the power of two that is not less that the given > number. > This calculation used to be implemented as a relatively inefficient loop > (that's why the issue 7192942 was created). > The implementation was improved with > http://hg.openjdk.java.net/jdk8/jdk8/jdk/rev/2e3cc7f599ca > > However it can be improved even more. I reused 7192942 number for this > propose. > > Would you please help with reviewing? > Here's the webrev: http://cr.openjdk.java.net/~igerasim/7192942/0/webrev/ > <http://cr.openjdk.java.net/%7Eigerasim/7192942/0/webrev/> > > I also created a benchmark test to make sure the improvement is observable. > Here's the jmh benchmark I used: > http://cr.openjdk.java.net/~igerasim/bench/powoftwo/src/main/java/org/benches/PowerOfTwoBench.java > > <http://cr.openjdk.java.net/%7Eigerasim/bench/powoftwo/src/main/java/org/benches/PowerOfTwoBench.java> > > Benchmark Mode Thr Cnt Sec Mean > Mean error Units > o.b.PowerOfTwoBench.benchPowerOfTwoA avgt 1 20 5 60.697 > 0.850 msec/op > o.b.PowerOfTwoBench.benchPowerOfTwoB avgt 1 20 5 53.013 > 0.940 msec/op > > The first line is for the current implementation and the second one is for > the proposed change. > Thus, the time gets reduced by 12%. > > Sincerely yours, > Ivan
