Author: Tom Kerrigan
Date: 20:32:22 04/12/03
Go up one level in this thread
On April 12, 2003 at 01:24:33, Robert Hyatt wrote: >I ran the test Tom suggested. Two different ways. > >First, four different threads. Results were a pretty even balance, varying >from 45-55, to 49-51 depending on the run. Not bad. > >Then two programs using two threads each, using a patched kernel that let me >lock a thread to a processor. Result was wildly varying. with a best of 60-40 >and a worst of 75-25. Why that is I have absolutely no idea. But even more >interesting is that the two threads seem to "lose" time for reasons unknown at >the moment. IE total time increases by about 30-50% which I don't understand at >all. This still points to some odd cache issue I believe, and it seems to >really influence SMT in a strange way... > >I'm trying to understand the two-thread results as they are probably related to >the problem Vincent pointed out last week (NPS about 1.5X a single using a dual >with no SMT at all.) Something is definitely fishy when I use threads. And >the balance between CPUS is nowhere near 50-50 for some reason... Hope you're not trying to pin that on SMT. -Tom
This page took 0.02 seconds to execute
Last modified: Thu, 15 Apr 21 08:11:13 -0700
Current Computer Chess Club Forums at Talkchess. This site by Sean Mintz.