Hyperthreading

Paul D. Buck
Paul D. Buck
Joined: 17 Jan 05
Posts: 754
Credit: 5,385,205
RAC: 0

> Is that copyrighted, Paul?

Message 5195 in response to message 5193

> Is that copyrighted, Paul? ;)

I am surprised I did not credit where I stole it from, but it must have been like this one ...

Blank Reg
Blank Reg
Joined: 18 Jan 05
Posts: 228
Credit: 40,599
RAC: 0

> > hmm.. slightly faster

Message 5196 in response to message 5187

> > hmm.. slightly faster yes.... 5x faster? I'm not sure about that...
> certainly
> > not in my experience anyway!
> >
> > Have you a list of timings? (link to one of your hosts experiencing
> this?)
>
>
> Well maybe we can just have a few people provide examples? Here is my
> computer, running at 3.06Ghz with HT as 2 processors:
>
> http://einsteinathome.org/host/20522
>
> It takes me roughly 84,500 to complete two WU's
>

Man you have a problem my p4 3.0 ht runs two WU from 38000 to 44000.

mewbysea
mewbysea
Joined: 17 Feb 05
Posts: 18
Credit: 109,821,900
RAC: 176,763

> > > hmm.. slightly faster

Message 5197 in response to message 5196

> > > hmm.. slightly faster yes.... 5x faster? I'm not sure about that...
> > certainly
> > > not in my experience anyway!
> > >
> > > Have you a list of timings? (link to one of your hosts experiencing
> > this?)
> >
> >
> > Well maybe we can just have a few people provide examples? Here is my
> > computer, running at 3.06Ghz with HT as 2 processors:
> >
> > http://einsteinathome.org/host/20522
> >
> > It takes me roughly 84,500 to complete two WU's
> >
>
> Man you have a problem my p4 3.0 ht runs two WU from 38000 to 44000.
>

Sounds like he's in the ball park actually since that 84,500 for two is 42,250 each.

My 3.2 Ghz HT running as one processor is about 37,000 per WU.

Biogenesis
Biogenesis
Joined: 11 Nov 04
Posts: 24
Credit: 140,834
RAC: 0

Woah, I'd no idea how slow

Woah, I'd no idea how slow the P4's were at this! A 2400+ Athlon I'm running in Windows does ~22k secs per WU http://einsteinathome.org/host/33405

I've got a 3000+ running Linux that still does ~37k secs per WU http://einsteinathome.org/host/34499/tasks the 43k secs results there are from my old CPU (1800+).

The linux/windows differences are discussed in a few other places (look in cafe einstein), but that slow processing on P4 vs Athlon XP is rather interesting.

kakrofoon
kakrofoon
Joined: 20 Feb 05
Posts: 2
Credit: 7,988
RAC: 0

Actually, I'm just stupid...

Actually, I'm just stupid... running on a single processor wasn't overloading my thermal solution, with it turned on it pegs out and clocks itself down. Time for a bigger fan...

Jordan Wilberding
Jordan Wilberding
Joined: 19 Feb 05
Posts: 162
Credit: 715,454
RAC: 0

> Woah, I'd no idea how slow

Message 5200 in response to message 5198

> Woah, I'd no idea how slow the P4's were at this! A 2400+ Athlon I'm running
> in Windows does ~22k secs per WU
> http://einsteinathome.org/host/33405

I am just curious. I can only get around 40K secs per WU on my Athlon XP 2400+. What would cause this?

such things just should not be writ so please destroy this if you wish to live 'tis better in ignorance to dwell than to go screaming into the abyss worse than hell

Jordan Wilberding
Jordan Wilberding
Joined: 19 Feb 05
Posts: 162
Credit: 715,454
RAC: 0

> > Woah, I'd no idea how

Message 5201 in response to message 5200

> > Woah, I'd no idea how slow the P4's were at this! A 2400+ Athlon I'm
> running
> > in Windows does ~22k secs per WU
> > http://einsteinathome.org/host/33405
>
> I am just curious. I can only get around 40K secs per WU on my Athlon XP
> 2400+. What would cause this?
>

I see you said you run Windows. I run Linux, but I don't see how it could cause this big of a difference.

such things just should not be writ so please destroy this if you wish to live 'tis better in ignorance to dwell than to go screaming into the abyss worse than hell

Paul D. Buck
Paul D. Buck
Joined: 17 Jan 05
Posts: 754
Credit: 5,385,205
RAC: 0

> > Woah, I'd no idea how

Message 5202 in response to message 5200

> > Woah, I'd no idea how slow the P4's were at this! A 2400+ Athlon I'm
> running
> > in Windows does ~22k secs per WU
> > http://einsteinathome.org/host/33405
>
> I am just curious. I can only get around 40K secs per WU on my Athlon XP
> 2400+. What would cause this?

Motherboard quality
Dual channel memory vs. single channel
Memory speed
Cache size
Overclocking/aggressive timings vs. normal timings
Bad luck
Evil gremlins, Gnolls & Trolls

Michael Berger
Michael Berger
Joined: 22 Jan 05
Posts: 36
Credit: 37,252
RAC: 0

> Well maybe we can just have

Message 5203 in response to message 5187

> Well maybe we can just have a few people provide examples? Here is my
> computer, running at 3.06Ghz with HT as 2 processors:
>
> http://einsteinathome.org/host/20522
>
> It takes me roughly 84,500 to complete two WU's

Jordan,

It seems that there is a serious configuration problem with your box. Here is an example of a similar box and its performance (take note of the Measured floating point speed):

Owner Jordan Wilberding
Created 19 Feb 2005 22:11:41 UTC
Total Credit 189.12
Recent average credit 28.48
CPU type GenuineIntel Intel(R) Pentium(R) 4 CPU 3.06GHz
Number of CPUs 2
Operating System Linux 2.6.10
Memory 501.5 MB
Cache 512 KB
Measured floating point speed 567.51 million ops/sec
Measured integer speed 1331.32 million ops/sec
Average upload rate 228.2 KB/sec
Average download rate 1619.21 KB/sec

Time to complete 2 WU's: about 84,500.00

Owner xxxxxx
Created 18 Feb 2005 17:25:39 UTC
Total Credit 22,572.89
Recent average credit 305.48
CPU type GenuineIntel Intel(R) Pentium(R) 4 CPU 3.06GHz
Number of CPUs 2
Operating System Microsoft Windows XP Professional Edition, Service Pack 2, (05.01.2600.00)
Memory 511.46 MB
Cache 976.56 KB
Measured floating point speed 1307.66 million ops/sec
Measured integer speed 1141.98 million ops/sec
Average upload rate 1.47 KB/sec
Average download rate 288.41 KB/sec

Time to complete 2 WU's: about 41,000.00

EDIT: After taking a peek at the listed specs for all of your boxes, it appears that your Measured floating point speed is about half of what it should be for each CPU type.

There's a fine line between fishing and standing on the shore looking like an idiot -- Steven Wright

Michael Berger
Michael Berger
Joined: 22 Jan 05
Posts: 36
Credit: 37,252
RAC: 0

After sifting thru the top

After sifting thru the top 1000 computers for this project, it has become painfully clear that LINUX is only successfully deployed on true multi-processor platforms. It does not perform well on single or HT CPU's of any type or model. All the examples show that the Measured floating point speed is halved. Below is an example of what could certainly be one of the best performers in this project (HT enabled and running Windows) pummeled by Linux into a less than desirable slug:

Owner Anonymous
Created 3 Dec 2004 18:08:05 UTC
Total Credit 7,179.38
Recent average credit 175.41
CPU type GenuineIntel Intel(R) Pentium(R) 4 CPU 3.60GHz
Number of CPUs 1
Operating System Linux 2.6.8
Memory 2026.78 MB
Cache 976.56 KB
Measured floating point speed 938.6 million ops/sec
Measured integer speed 2687.19 million ops/sec
Average upload rate 147.51 KB/sec
Average download rate 1257.19 KB/sec
Average turnaround time 0.77 days

Time to complete 1 WU: about 34,000

My AMD 1.3 GHz Athlon from 2000 can almost keep pace with this monster CPU (Time to complete 1 WU: about 36,000)!

There's a fine line between fishing and standing on the shore looking like an idiot -- Steven Wright

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