Emery Berger emery at cs.umass.edu
Thu Dec 20 18:36:13 UTC 2007

Hi all,
I know that Novell has used Hoard to improve performance of its VM, but in that VM, Java objects are allocated from the C heap. Given Tony's comments, I would not expect Hoard to make any difference for pure Java code running in HotSpot, but could certainly impact performance for native libraries. I'd be interested to hear the results.
-- Emery (apparently a.k.a. "Mr. Hoard" :))
Emery Berger
Assistant Professor
Dept. of Computer Science
University of Massachusetts Amherst
http://www.cs.umass.edu/~emery <http://www.cs.umass.edu/~emery> 


From: Tony Printezis [mailto:tony.printezis at sun.com]
Sent: Thu 12/20/2007 11:21 AM
To: Keith Holdaway
Cc: hotspot-gc-dev at openjdk.java.net; Emery Berger
Subject: Re: HOARD


Hi. You should just be able to use Hoard instead of whatever malloc
comes with the OS without and OS changes.

I just don't know whether the JVM will actually benefit from Hoard
though. We don't do that much malloc within the JVM (we manage all Java
objects ourselves). It'd be a nice exercise, though, if you're willing
to try it and share your experience on the list! :-) Maybe, it could be
a win if you have a native library that calls malloc extensively and
from many threads.

I'm CCing Mr Hoard so that he can share his wisdom. :-)

Regards and happy holidays everyone!


Keith Holdaway wrote:
> I researched HOARD:
> http://developers.sun.com/solaris/articles/multiproc/multiproc.html
> The Hoard memory allocator is a fast, scalable, and memory-efficient memory allocator. It runs on a variety of platforms, including Linux, Solaris, and Windows. Hoard is a drop-in replacement for malloc() that can dramatically improve application performance, especially for multithreaded programs running on multiprocessors.
> Is this purely an OS change; or does one have to make changes to the VM source to use HOARD instead of malloc etc?
> keith
> Keith R Holdaway
> Java Development Technologies<http://rdwss.na.sas.com/mti/jdt/default.aspx>
> SAS...  The Power to Know
> Carpe Diem ...

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