Low-Overhead Heap Profiling

Kirk Pepperdine kirk.pepperdine at gmail.com
Fri Jun 26 07:08:36 UTC 2015


Hi Tony,

>> 
>> I would think that the size based sampling would create a size based bias in your sampling. 
> 
> 
> That’s actually true. And this could be good (if you’re interested in what’s filling up your eden, the larger objects might be of more interest) or bad (if you want to get a general idea of what’s being allocated, the size bias might make you miss some types of objects / allocation sites).
> 
> 

IME, if I see allocation rates > ~500MB/sec I know there are some significant wins I can make by tuning allocation hotspots. So, I’m interested in frequent allocations no matter what the size.
> 
>> Since IME, it’s allocation frequency is more damaging to performance, I’d prefer to see time boxed sampling
> 
> 
> Do you mean “sample every X ms, say”?
> 
> 

I don’t find that sampling rate has to be that high to find hot allocation sites.

Kind regards,
Kirk Pepperdine

> 
> Tony
> 
> 
> 
>> 
>> Kind regards,
>> Kirk Pepperdine
>> 
> 
> 
> -----
> 
> Tony Printezis | JVM/GC Engineer / VM Team | Twitter
> 
> @TonyPrintezis
> tprintezis at twitter.com

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/hotspot-gc-dev/attachments/20150626/cac8746f/attachment-0001.html>


More information about the hotspot-gc-dev mailing list