<html><body>On 01:51 am, matusis@matusis.com wrote:<br /><br />>I am running a poll reactor with Twisted 2.2 on 2.6.11 kernel.<br />>"top" currently shows 80-90% CPU utilization for this twistd process.<br />>We have not switched to epoll Twisted 2.5 yet, although we are planning to.<br /><br />Hi, Alec!  Nice to hear that you're using Twisted in such a demanding situation.<br /><br />>Where should we expect a better performance: on Woodcrest 5140 with bigger<br />>L2 or on Opteron 2216 with faster RAM access? We need to order the new box<br />>tomorrow afternoon, so if someone could reply today, it'd be great for us!<br /><br />I'm only replying to this message because of your extremely short timeframe.  I have _no_ reliable data that I would feel comfortable making a decision based on, but then, either of these systems will likely be adequate to your purposes.  So, take all this with a grain of salt, and I hope you get something better.<br /><br />My new MacBook - a core 2 duo with 4MB of cache - slightly (10% time difference) outstrips my desktop work machine - an opteron64 with 1MB of cache - when running the Twisted unit tests.  The Opteron is almost 8 months old now, but the MacBook is a laptop.  I am being intentionally vague about the rest of the specs here to stress the anecdotal and unscientific nature of this knowledge :-).<br /><br />However, this result doesn't surprise me, and I guess it may generalize to the current generation of hardware, which is to say, Intel wins.  RAM is important, as is raw CPU speed, but L2 cache is _the_ major determinant of Python's performance in all of the cross-machine profiling I've done.  That is to say, this experiment, and this one other time I think I ran some stuff on a PowerPC or a MIPS or something (those are different, right?).<br /><br />Good luck on making the right choice here with such tight constraints!<br /></body></html>