Simon Jolle sjolle wrote:
In 64-bit mode I wouldn't be surprised if the same usage would come out to 500MB+ memory usage.
Again why?
Because 64-bit apps in general use more memory
SSH 64-bit: root 4193 0.0 0.0 21932 1272 ? Ss Jan29 1:00 /usr/sbin/sshd
SSH 32-bit: root 19725 0.0 0.0 4392 276 ? Ss 2007 7:52 /usr/sbin/sshd
500%+ more memory
SNMPD 64-bit: root 4146 0.0 0.0 88316 5952 ? S Jan29 2:58 /usr/sbin/snmpd -Lsd -Lf /dev/null -p /var/run/snmpd.pid -a
SNMPD 32-bit: root 19928 0.0 0.1 14436 2032 ? S 2007 42:07 /usr/sbin/snmpd -Lsd -Lf /dev/null -p /var/run/snmpd -a
600%+ more memory
Apache 64-bit: apache 24540 0.3 0.2 108212 13700 ? S 11:17 0:28 /usr/sbin/httpd
Apache 32-bit(same module config): apache 28602 0.0 0.6 16136 6884 ? S 08:19 0:00 /usr/sbin/httpd
600%+ more memory
List goes on..
I don't mean to imply that it's certain to use 2-3x more memory, but in my experience it appears that 64-bit apps use much more memory than 32-bit. I've read they can use up to 2x more memory, but clearly in some cases it can go way beyond 2x.
It's just not worth it for most things. I tried migrating a web server that runs Ruby on Rails/FastCGI from 32-bit to 64-bit and experienced a 300% increase in memory utilization and about a 75% reduction in performance. (before that my goal was to try to make everything 64-bit to make it easier to manage).
nate