On 05/24/2011 05:57 PM, Fernando Cassia wrote: > On Tue, May 24, 2011 at 13:47, Andrew Haley <aph@xxxxxxxxxx> wrote: >> Ever since >> Compressed OOPs became the default there's no big advantage to running >> 32-bit Java, at least on HotSpot. > > ---- > What are the performance characteristics of 64-bit versus 32-bit VMs? > > Generally, the benefits of being able to address larger amounts of > memory come with a small performance loss in 64-bit VMs versus running > the same application on a 32-bit VM. This is due to the fact that > every native pointer in the system takes up 8 bytes instead of 4. But because of Compressed OOPs that's no longer true, and you get the advantage of > ... some additional registers which it can use to generate > more efficient native instruction sequences. These extra registers > increase performance to the point where there is often no performance > loss at all when comparing 32 to 64-bit execution speed. and you also get the advantage of longs fitting in a register. Andrew. -- users mailing list users@xxxxxxxxxxxxxxxxxxxxxxx To unsubscribe or change subscription options: https://admin.fedoraproject.org/mailman/listinfo/users Guidelines: http://fedoraproject.org/wiki/Mailing_list_guidelines
