[AG-TECH] inquiry on the hardware specs...
Justin Binns
binns at mcs.anl.gov
Wed Oct 22 14:28:40 CDT 2003
Our past experience with HyperThreading indicates that it does help under
Windows, but that the Linux scheduler is not hyper-threading friendly, and
it can actually *decrease* performance (that is, the scheduler in Linux
already does a pretty good job of keeping the processor(s) busy, having the
processors themselves double-scheduled doesn't help any, it just creates
contention for various critical memory regions). We haven't really played
with it exhaustively for a while, though - more recent kernels (particularly
the 2.6 series) may be able to take better advantage of HT technology.
Justin
-----Original Message-----
From: owner-ag-tech at mcs.anl.gov [mailto:owner-ag-tech at mcs.anl.gov] On Behalf
Of Randy Groves
Sent: Wednesday, October 22, 2003 2:13 PM
To: ag-tech at mcs.anl.gov
Subject: Re: [AG-TECH] inquiry on the hardware specs...
The hyperthreading note below is intriguing - does it REALLY give us a
boost by simulating two extra processors? Any other experience here?
-randy
At 08:46 AM 10/21/2003, Harri Salminen wrote:
>I happened to notice that when the machine was temporarily in a single
>processor mode (settable from BIOS) the AG lobby caused some problems
>due to constant 100% CPU use but in dual processor (actually
>hyperthreading shows it as 4 CPUs) mode it worked OK. The display vic
>apparently is singlethreading and reserves only one processor up to
>it's limit leaving enough CPU for all the rest including windows XP
>pro, dppt, beacon, vnc and gentner AXP-800 control program.
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