Re: [infinispan-dev] CHM or CHMv8?
Why not. Only doubt I'd have is that other usages of the CHM are - I guess
- services registry and similar configuration tools, for which write
performance is irrelevant: your test measured puts, are there drawbacks on
gets or memory usage?
Recently you changed all (most?) CHM creations to use a consistent factory,
maybe we could improve on that by actually using a couple of factories
which differentiate on the intended usage of the CHM: for example some maps
who change very infrequently - mostly during boot or reconfiguration, maybe
even topology change - could be better served by a non concurrent structure
using copy-on-wrtite.
Sanne
On 19 Apr 2013 08:48, "Dan Berindei" <dan.berindei(a)gmail.com> wrote:
+1 to make CHMv8 the default on JDK6 and JDK7
But I'm not convinced we should make it the default for JDK8 - even though
we don't know exactly what we're getting with the JDK's implementation.
On Fri, Apr 19, 2013 at 5:39 AM, David M. Lloyd <david.lloyd(a)redhat.com>wrote:
> On 04/18/2013 09:35 PM, Manik Surtani wrote:
> > Guys,
> >
> > Based on some recent micro benchmarks I've been doing, I've seen:
> >
> > MapStressTest configuration: capacity 100000, test running time 60
> seconds
> > Testing mixed read/write performance with capacity 100,000, keys
> 300,000, concurrency level 32, threads 12, read:write ratio 0:1
> > Container CHM Ops/s 21,165,771.67 Gets/s 0.00 Puts/s
> 21,165,771.67 HitRatio 100.00 Size 262,682 stdDev 77,540.73
> > Container CHMV8 Ops/s 33,513,807.09 Gets/s 0.00 Puts/s
> 33,513,807.09 HitRatio 100.00 Size 262,682 stdDev 77,540.73
> >
> > So under high concurrency (12 threads, on my workstation with 12
> hardware threads - so all threads are always working), we see that
> Infinispan's CHMv8 implementation is 50% faster than JDK6's CHM
> implementation when doing puts.
> >
> > We use a fair number of CHMs all over Infinispan's codebase. By
> default, these are all JDK-provided CHMs. But we have the option to switch
> to our CHMv8 implementation by passing in
> -Dinfinispan.unsafe.allow_jdk8_chm=true.
> >
> > The question is, should this be the default? Thoughts, opinions?
>
> The JDK's concurrency code - especially CHM - changes all the time.
> You'd be very well-served, in my opinion, to go with something like
> CHMv8 just because you could be so much more sure that you'll have more
> consistent (and possibly better, but definitely more consistent)
> performance across all JVMs, instead of being at the mercy of whatever
> particular implementation happens to run on whatever JVM.
>
>
> --
> - DML
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