RE: Hyperthreading

[James Bourne]

On Wed, 17 Apr 2002, Martin J. Bligh wrote:

> > I've seen some Intel bench's and they are specing an increase of 0% to 30%
> 
> I think I'd be less cynical about benchmark results that didn't come from the
> people trying to sell  the product ;-)
> 
[...]
> Real world benchmarks from people other than Intel should make interesting
> reading .... I think we need some more smarts in the OS to take real advantage
> of this (eg using the NUMA scheduling mods to create cpu pools of 2 "procs"
> for each pair, etc) ... will be fun ;-)

Well, here I have some.

The tests involved kernel compiled (2.4.18) from a make mrproper, single
nbench, and unixbench (likely the most useful).

The output from tests can be found at http://www.hardrock.org/HT-results/

Results consist of (all with hyperthreading on and off):
o timed make bzImage and make modules using -j2 -j4 and -j6.
o BYTEmark output (single run)
o BYTE UNIX Benchmarks (Version 4.1.0) log, report, and times
o output from /proc/cpu
o output from /proc/interrupts
o output from dmesg (sorry, one of them has the top clipped).
o output from lspci -v

many concurrent tasks then hyperthreading makes sense.  Many
concurrent systems (the -j4 and -j6 kernel compiles for example)
do see improvements.  Although this is not a very analytical test, I don't
have time for 10 iterations of each to get a better set of numbers.

Thanks to all and regards,
James Bourne

> 
> M.
> 

-- 
James Bourne, Supervisor Data Centre Operations
Mount Royal College, Calgary, AB, CA
www.mtroyal.ab.ca

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