On Thu, 13 Jan 2005 21:38:08 +0100 Andrea Venturoli
<[EMAIL PROTECTED]> wrote:
>Anthony Atkielski wrote:
>> Andrea Venturoli writes:
>>
>> AV> Not exactly the same algorithm and on different set of data.
>>
>> But similar machine instructions, perhaps?
>
>Yes, both numerical computations.
>
> The other AMD processor, on my server, dramatically overheated for 8-12
> hours at a time (process stuck in a loop--I never found out why). It
> damaged something that failed intermittently at first (segment
> violations in the kernel and in daemons that should never have such
> problems), then
Andrea Venturoli writes:
AV> I've come to the same conclusion. Still I can't put this together with
AV> 100% load on both processors. If, as someone said, there is only one
AV> FPU, *how* are these figures coming out???
The operating system tracks a dispatch of a processor into a process
thread.
Anthony Atkielski wrote:
Andrea Venturoli writes:
AV> Not exactly the same algorithm and on different set of data.
But similar machine instructions, perhaps?
Yes, both numerical computations.
Basically one thread would model geometry and the other would mesh it.
Frequent stall would arise, as the t
Olivier Nicole writes:
ON> It was dead for good, well it is still dead as a matter of fact :)
The AMD processor on my XP system overheated and stalled a few times, before
I realized that the (brand-new) fan had failed. It still runs okay now,
though, with a reliable fan.
The other AMD processor
Andrea Venturoli writes:
AV> Not exactly the same algorithm and on different set of data.
But similar machine instructions, perhaps?
AV> Yes.
Just the contention for the FPU alone might have had the effect of
single-threading the workload. That plus the SMP overhead might give
you a zero or ne
> Did it start up when you replaced the fan, or was it gone for good?
It was dead for good, well it is still dead as a matter of fact :)
> I thought all the boxed P4 processors came with their own fan, so there
> should never be a case in which a PC is sold with a P4 but no CPU fan.
So did I, so
Anthony Atkielski wrote:
Where these computations in which all threads were doing pretty much the
same thing?
Not exactly the same algorithm and on different set of data.
And was it floating-point?
Yes.
(Doesn't the processor have just one FPU, or something like that?)
I don't really know (I made
On Thu, 13 Jan 2005 02:11:27 +0100 Anthony Atkielski
<[EMAIL PROTECTED]> wrote:
>Scott Bennett writes:
>
>SB> I notice that the 5.2.1 boot messages refer to the second core as an
>SB> AP, which I'm guessing stands for "attached processor". If that
>SB> guess is correct, then it means that onl
off-topic, but...
On Thu, Jan 13, 2005 at 01:43:54AM +0100, Anthony Atkielski wrote:
> AV> BTW, an old AMD 2000 XP+ would in any case almost outperform a P4 3GHz,
> AV> but that's another story.
>
> An AMD processor will also melt or catch fire if the CPU fan fails,
> whereas an Intel processor w
Subhro writes:
S> This *used* to be true. I am using a AMD64 3000+ and the idle
S> temperature is 28C. The room temp is around 12-14C. After asking this
S> kid to crunch FPs for over 16 hrs, the processor temperature rose to
S> only 38C. I am not using any special cooling gears, just the stock
S>
> -Original Message-
> From: [EMAIL PROTECTED] [mailto:owner-freebsd-
> [EMAIL PROTECTED] On Behalf Of Anthony Atkielski
> Sent: Thursday, January 13, 2005 6:14
> To: freebsd-questions@freebsd.org
> Subject: Re: Hyperthreading hurts 5.3?
>
> Andrea Venturoli
Olivier Nicole writes:
ON> Not always true, I had a P4 1.5 die on me for lack of fan.
I understood that all recent Intel processors will first slow the clock
and then halt completely if the die temperature rises too much, but
there may be exceptions (or perhaps some processors run so hot that the
> An AMD processor will also melt or catch fire if the CPU fan fails,
> whereas an Intel processor won't. I found this out the hard way, and so
Not always true, I had a P4 1.5 die on me for lack of fan.
Now what was tha company selling a new box with no fan on the CPU is
another story...
Olivier
Scott Bennett writes:
SB> I notice that the 5.2.1 boot messages refer to the second core as an
SB> AP, which I'm guessing stands for "attached processor". If that
SB> guess is correct, then it means that only the first core is able to
SB> perform certain functions, and the AP core has to get the f
On Jan 12, 2005, at 12:34 AM, Timothy Luoma wrote:
ps - thanks to all who responded. I'm going to disable HT, boot to
FreeBSD and try another large file transfer and see if I see the large
delays. If no, I'll copy the files I need off the XP drive and
reinstall XP.
Ok, well I disabled HT and s
Andrea Venturoli writes:
AV> FWIW I tried numerical computations on a P4 with HT enabled: I expected
AV> using 2 threads might give *at least slightly* better results, but I
AV> could come to the conclusion that with 1, 2 or 4 threads the performance
AV> gain (or loss) was exactly zero.
Where the
On Wed, 12 Jan 2005 18:45:56 +0100 Anthony Atkielski
<[EMAIL PROTECTED]> wrote:
>Scott Bennett writes:
>
>SB> Well, no, not exactly. The dual-cored CPUs share certain resources
>SB> on the chip that are not shared in a multi-CPU situation, and that sharing
>SB> means certain operations
Anthony Atkielski wrote:
From what you say and from what I've read today, it sounds like
hyperthreading comes close to providing two separate processors for
heterogenous system loads (where each hyperthread is using slightly
different processor resources at any given instant), but it may not buy
mu
On 2005-01-12 19:23, Anthony Atkielski <[EMAIL PROTECTED]> wrote:
> Giorgos Keramidas writes:
>
> GK> The 'separate file' is NOTES. This file is actually the complete
> GK> reference of options that the kernel supports, so it's not like the SMP
> GK> option is hidden or something.
>
> I must have
On Wed, 12 Jan 2005 00:02:37 -0500, Bryan Fullerton <[EMAIL PROTECTED]> wrote:
> I'm experiencing some strangeness with a uniproc HTT-capable machine
> and SATA with either SMP or non-SMP kernels, so I'll try turning off
> HTT in the BIOS later this week and see if that helps.
Well, this is inter
On Wed, 12 Jan 2005 18:29:01 +1300, Jonathan Chen <[EMAIL PROTECTED]> wrote:
> On Wed, Jan 12, 2005 at 12:02:37AM -0500, Bryan Fullerton wrote:
> > By default the system will detect a HTT processor, but can only launch
> > the second 'virtual' CPU core if you recompile the kernel with the SMP
> > o
Giorgos Keramidas writes:
GK> The 'separate file' is NOTES. This file is actually the complete
GK> reference of options that the kernel supports, so it's not like the SMP
GK> option is hidden or something.
I must have a magic special version of FreeBSD:
# cd /usr/src/sys/i386/conf
# grep SMP *
On 2005-01-12 18:41, Anthony Atkielski <[EMAIL PROTECTED]> wrote:
> Giorgos Keramidas writes:
>
> GK> You need to enable SMP too, to allow the FreeBSD kernel to use the
> GK> second (hyper-threaded) CPU.
>
> I found it, in a file called SMP. Why is the SMP option tucked away in
> a separate file?
Scott Bennett writes:
SB> Well, no, not exactly. The dual-cored CPUs share certain resources
SB> on the chip that are not shared in a multi-CPU situation, and that sharing
SB> means certain operations have to be handled differently. An MP setup has
SB> separate cache and TLB managment in ea
Giorgos Keramidas writes:
GK> You need to enable SMP too, to allow the FreeBSD kernel to use the
GK> second (hyper-threaded) CPU.
I found it, in a file called SMP. Why is the SMP option tucked away in
a separate file?
I stuck this into the config and rebuilt the kernel. Seems to run fine.
I see
On 2005-01-11 22:18, Chuck Swiger <[EMAIL PROTECTED]> wrote:
>David Kelly wrote:
>>> (disabling HT will apparently mean I have to reinstall XP on the
>>> other drive.
>>
>> What does XP have to do with it? IIRC on Dell its F2 during the
>> power-on diagnostics to reach the built-in BIOS config. Th
On 2005-01-12 07:20, Anthony Atkielski <[EMAIL PROTECTED]> wrote:
> Jonathan Chen writes:
> JC> Not true on 5.3+ GENERIC systems. If you look at dmesg, you'll see the
> JC> second virtual CPU launched as well as the extra column in top(1) if
> JC> you enable HTT in the BIOS.
>
> Well, now I'm confu
On Wed, 12 Jan 2005 06:21:18 +0100 Anthony Atkielski
<[EMAIL PROTECTED]> wrote:
>Olivier Nicole writes:
>
>ON> Maybe for the same reason you should better not use a non-SMP kernel
>ON> if you have 2 CPU in your box.
>
>Is a hyperthreading CPU identical to a second CPU from the software's
>sta
On 2005-01-11 23:52, Timothy Luoma <[EMAIL PROTECTED]> wrote:
>On Jan 11, 2005, at 8:43 PM, Giorgos Keramidas wrote:
>>On 2005-01-11 19:52, "Timothy J. Luoma" <[EMAIL PROTECTED]> wrote:
>>>
>>> summary: should I disable hypertheading in the BIOS when running 5.3?
>>> [...]
>>> If YES, I wasn't cle
Jonathan Chen writes:
JC> Not true on 5.3+ GENERIC systems. If you look at dmesg, you'll see the
JC> second virtual CPU launched as well as the extra column in top(1) if
JC> you enable HTT in the BIOS.
Well, now I'm confusing. I have an Asus P4P800-E Deluxe MB with an
Intel P4 processor mounted
On Jan 11, 2005, at 9:09 PM, David Kelly wrote:
The benefits of HT are too few for me to risk trashing the fs now its
full.
That's a good enough reason for me.
Iif YES, I wasn't clear if people meant "disable in BIOS" or just some
configuration setting in a *.conf file.
In the BIOS.
Thanks...
(dis
On Wed, Jan 12, 2005 at 12:02:37AM -0500, Bryan Fullerton wrote:
> On Tue, 11 Jan 2005 23:52:11 -0500, Timothy Luoma <[EMAIL PROTECTED]> wrote:
> >
> > sorry to be dense, but which should be enough, BIOS or conf file?
> >
> > is the default to use or not use hyperthreading in the kernel/conf?
>
> Is a hyperthreading CPU identical to a second CPU from the software's
> standpoint? If not, what are the differences?
I am not sure, but it is some how detected as 2 CPUs
FreeBSD/SMP: Multiprocessor System Detected: 4 CPUs
cpu0 (BSP): APIC ID: 0
cpu1 (AP): APIC ID: 1
cpu2 (AP): APIC ID:
Olivier Nicole writes:
ON> Maybe for the same reason you should better not use a non-SMP kernel
ON> if you have 2 CPU in your box.
Is a hyperthreading CPU identical to a second CPU from the software's
standpoint? If not, what are the differences?
--
Anthony
__
> I'm personally unclear why it'd be necessary to disable HTT in the
> BIOS if you're using a non-SMP kernel on a uniproc box.
Maybe for the same reason you should better not use a non-SMP kernel
if you have 2 CPU in your box.
Try to keep hardware (BIOS) and OS consistent, even if they are
suppos
On Tue, 11 Jan 2005 23:52:11 -0500, Timothy Luoma <[EMAIL PROTECTED]> wrote:
>
> sorry to be dense, but which should be enough, BIOS or conf file?
>
> is the default to use or not use hyperthreading in the kernel/conf?
By default the system will detect a HTT processor, but can only launch
the se
On Jan 11, 2005, at 8:43 PM, Giorgos Keramidas wrote:
On 2005-01-11 19:52, "Timothy J. Luoma" <[EMAIL PROTECTED]> wrote:
summary: should I disable hypertheading in the BIOS when running 5.3?
[...]
If YES, I wasn't clear if people meant "disable in BIOS" or just some
configuration setting in a *.co
On Jan 11, 2005, at 9:18 PM, Chuck Swiger wrote:
David Kelly wrote:
(disabling HT will apparently mean I have to reinstall XP on the
other
drive.
What does XP have to do with it? IIRC on Dell its F2 during the
power-on diagnostics to reach the built-in BIOS config. That is where
HT is to be disa
David Kelly wrote:
(disabling HT will apparently mean I have to reinstall XP on the other
drive.
What does XP have to do with it? IIRC on Dell its F2 during the power-on
diagnostics to reach the built-in BIOS config. That is where HT is to be
disabled.
If you install and configure many flavors of
Timothy J. Luoma wrote:
summary: should I disable hypertheading in the BIOS when running 5.3?
It would certainly be worth trying this and seeing whether running as a purely
single-proc system performs better for you.
It's not exactly as if HyperThreading evolved out of a sensible plan like
"let
On Jan 11, 2005, at 6:52 PM, Timothy J. Luoma wrote:
summary: should I disable hypertheading in the BIOS when running 5.3?
Background info:
I have a new Dell Dimension 3000 running 5.3.
I noticed some huge pauses when copying a large # of files across the
network. Googling around found some infor
On 2005-01-11 19:52, "Timothy J. Luoma" <[EMAIL PROTECTED]> wrote:
>
> summary: should I disable hypertheading in the BIOS when running 5.3?
> [...]
> If YES, I wasn't clear if people meant "disable in BIOS" or just some
> configuration setting in a *.conf file.
FWIW, that should be enough, as fa
summary: should I disable hypertheading in the BIOS when running 5.3?
Background info:
I have a new Dell Dimension 3000 running 5.3.
I noticed some huge pauses when copying a large # of files across the
network. Googling around found some information about earlier versions of
5.x and Hypert
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