On Wed, 15 Dec 2010, Doug Hughes wrote: > On 12/15/2010 11:41 AM, Jason Qualkenbush wrote: >> I'm being asked to build a 32bit system. There is no specific reason >> for this to be 32bit except my boss likes that there are less >> libraries to install. This is a CentOS 5 install and they way things >> work, this will remain a 32bit install for the next four years (until >> a hardware refresh). >> >> It's hard for me to explain why, but that just feels dirty to me. >> When in performance tuning classes, it was understood that you want >> 64bit over 32bit. I can't use "people told me 64bit is better", but I >> keep reading "unless you have a specific reason for 32bit, choose 64". >> I need something that has details. >> >> Can someone provide a link to why you want to install 64bit? The best >> I could come up with is this article: http://kerneltrap.org/node/2450 >> which explains how PAE works. Does 64 bit matter for large files? >> Network performance? >> >> I'm irritated that I'm being forced to build this thing as 32bit. >> It's a RSyslog, Cacti, Nagios system, and if I build it, I'm pretty >> much signing my name to this. It becomes a "JQ built server". I just >> feel like going 64bit is better for "future proofing" this thing than >> 32bit. >> >> > If you are just doing 32 bit math and operations, 32bit would actually > be slightly faster, but you might be hard pressed to measure it. You > have half as much memory activity to do for instruction and word fetch > operations that are specified as 'long', and effectively more cache > capacity. > > However, yes, you run into that nasty 2GB file limit with 32 bit, and > 4GB of ram compounded by virtual memory choices. For network performance > it shouldn't matter a bit.
True, although the fact that a 64 bit build has twice as many registers to use can make even more of a difference. There's also the fact that there are many ops that are optional on 32 bit that are mandatory on 64 bit processors, so software compiled for 64 bit can assume that the commands are available, but software compiled for 32 bit must be compiled for the least common denominator, and can't count on the ops being available. David Lang _______________________________________________ Discuss mailing list [email protected] https://lists.lopsa.org/cgi-bin/mailman/listinfo/discuss This list provided by the League of Professional System Administrators http://lopsa.org/
