I noticed that the same exact build on i7-920 (4 CPUs) consumes ~15%
more user CPU when run with -j 8 compared to -j 4.
Hyper-threading is enabled so top shows 8 CPUs.
Why would user time be higher in a hyper-threaded run?
Yuri
___
freebsd
I noticed that the same exact build on i7-920 (4 CPUs) consumes ~15% more
user CPU when run with -j 8 compared to -j 4.
Hyper-threading is enabled so top shows 8 CPUs.
Why would user time be higher in a hyper-threaded run?
because it doesn't count actual instruction executed but - as name
I'n on a system with the CPU specs you see below.
I'm planning to update the system to 7.0 and want to ask about the
enabeling or disablening of hyper threading in BIOS.
What I've seen on my current system is that when I enable hyper
threading my cpu-graph only shows up to 50% in gkrelm
On Mar 26, 2005, at 2:39 PM, [EMAIL PROTECTED] wrote:
This is the kind of disinformation I have been
referring to
What in particular are you referring to?
___
freebsd-questions@freebsd.org mailing list
On Mar 26, 2005, at 5:33 PM, [EMAIL PROTECTED] wrote:
Yes, the theory is very nice; you've done a nice
job reading Intel's marketing garb.
What theory? All I see is On Mar 26, 2005, at 5:33 PM, [EMAIL PROTECTED]
wrote:
___
If you think that then you are either a fool or
an old fool..
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Tue, 29 Mar 2005 06:43:59 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
And the circumstances that you have
[EMAIL PROTECTED] writes:
If you think that then you are either a fool or
an old fool..
I've never encountered a situation in which experience was a
disadvantage.
--
Anthony
___
freebsd-questions@freebsd.org mailing list
2005 21:02:40 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
If you think that then you are either a fool or
an old fool..
I've never encountered a situation in which experience was a
disadvantage.
--
Anthony
___
freebsd-questions@freebsd.org
, 29 Mar 2005 21:02:40 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
If you think that then you are either a fool or
an old fool..
I've never encountered a situation in which experience was a
disadvantage.
--
Anthony
.
-Original Message-
From: Guillermo Garcia-Rojas [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Tue, 29 Mar 2005 14:03:15 -0600
Subject: Re: hyper threading.
Stop feeding this troll, he has been banned from de DragonFly BSD list
for his stupid comments, his e-mail address doesn't
[EMAIL PROTECTED] writes:
Thats because you seem unable to grasp modern concepts.
None were under discussion.
If you think that performance criteria
of modern controllers and processors are the same
as 30 years ago, then you are incapable of commenting
on anything modern.
The principles
are so fast that most people don't notice,
as is evidenced by this thread.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Tue, 29 Mar 2005 22:20:31 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
Thats because you seem unable
[EMAIL PROTECTED] wrote:
The principles of modern controllers are surprisingly similar to those
of old controllers. The biggest change is that the PC world is only
now discovering what mainframe designers knew 40 years ago.
PC Designers knew it 20 years ago. When I designed the
On Tue, 2005-03-29 at 22:20 +0200, Anthony Atkielski wrote:
[EMAIL PROTECTED] writes:
Thats because you seem unable to grasp modern concepts.
None were under discussion.
As far as you can see, which shows the limit of your percption.
If you think that performance criteria
of modern
--- Anthony Atkielski [EMAIL PROTECTED]
wrote:
[EMAIL PROTECTED] writes:
Polling is simply unecessary in most cases. You
could get
better performance using an em driver and setting
max
ints to whatever is optimal for your system.
Polling adds
latency and over head for no good
Boris Spirialitious writes:
If you understood what I said, then you wouldn't
say what you said, because its just plain wrong.
I've written code that proves it right. Someone once told me that a
80286 couldn't handle ordinary terminal communications at speeds of
38400 bps. I proved that it
properly has zero overhead
for the O/S
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Mon, 28 Mar 2005 06:03:00 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
Polling is simply unecessary in most cases. You could get
better
better way to reduce interrupts without
poisoning your system with extra overhead.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Mon, 28 Mar 2005 16:49:20 +0200
Subject: Re: hyper threading.
Boris Spirialitious writes:
If you understood
[EMAIL PROTECTED] writes:
Things have changed a bit since then, so I doubt that
proof has any relevance.
The principles haven't changed at all.
Servicing interrupts is an extremely high-overhead activity. There's a
minimum amount of time it takes, no matter how short the interrupt
routine.
good hardware, polling has negative
effects on performance. It ads overhead for no
additional benefit.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Mon, 28 Mar 2005 20:14:52 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes
[EMAIL PROTECTED] writes:
Do you know how MAX_INTS and Device Polling
work?
I know how device polling works. MAX_INTS is the sort of identifier
that probably occurs in seven trillion lines of code in the world, so I
have no idea what it means.
I can tell that you don't so why are you
And the circumstances that you have described
have nothing to do with modern computing, so
as I said, its irrelevant.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Tue, 29 Mar 2005 00:03:07 +0200
Subject: Re: hyper threading.
[EMAIL
[EMAIL PROTECTED] writes:
And the circumstances that you have described
have nothing to do with modern computing, so
as I said, its irrelevant.
The circumstances have not changed in modern computing. That's one
reason why 30-year-old operating systems like UNIX remain popular.
--
Anthony
Paul A. Hoadley writes:
Here are some measurements. A few weeks ago I ran Unixbench 4.1.0
(/usr/ports/benchmarks/unixbench) on a P4 2.8GHz with and without
hyperthreading enabled. I note a slight difference in the 10 minute
load average in favour of the uniprocessor run (0.00 vs 0.10 in the
[EMAIL PROTECTED] writes:
You can argue the technical theory all you want, but the
measurements say otherwise.
You have to ensure that you're doing the right measurements.
FreeBSD 4.9 - Load: 38% (I put this in for fun :-)
Freebsd 5.4-Pre UP (no HT) - Load: high 55-60% range
FreeBSD
[EMAIL PROTECTED] writes:
When you get your machine running without a kernel
let me know. The kernel is the key to the O/S. If you
don't need networking and don't have many interrupts,
then it probably doesnt matter that much.
The kernel represents only a small part of total system
Right. Thats what I said. You'll killl your networking.
So you don't want HT or SMP on a Server. Thats
what most MP machines are used for.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Sun, 27 Mar 2005 12:33:36 +0200
Subject: Re: hyper
2005 17:23:40 -0800
Subject: Re: hyper threading.
Well you've proven than if you pick your benchmark you can get the
result you want.
So what that says it that the kernel network code doesn't get any
benefit from HT - given that HT is supposed to benefit diverse user
tasks and no multiple copies
: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Sun, 27 Mar 2005 12:33:36 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
You can argue the technical theory all you want, but the
measurements say otherwise.
You have to ensure that you're doing the right
[EMAIL PROTECTED] writes:
You know, you spout all of this wonderful theory without considering
the quality of the implementation.
Somethings can be derived directly from theory. If you know the design
of the hardware, you can predict that two processors will provide x%
increment of throughput
[EMAIL PROTECTED] writes:
Right. Thats what I said. You'll killl your networking.
Beyond a certain network load, you have to increase the number of timer
interrupts per second no matter how fast your processors are or how many
of them you have, if you are polling your I/O interfaces instead of
On Saturday 26 March 2005 22:45, Anthony Atkielski wrote:
[EMAIL PROTECTED] writes:
Yes, the theory is very nice; you've done a nice
job reading Intel's marketing garb.
I haven't read their marketing materials. I'm simply going by the
technical descriptions I've read of the architecture.
RW writes:
Multiple processors can run multiple processes at the same time. A HT
processor can only run two threads from the same process.
This is incorrect. HT processors don't care where the threads come
from; it is possible to run threads from two completely different
processes on the same
On Sunday 27 March 2005 22:33, Anthony Atkielski wrote:
RW writes:
Multiple processors can run multiple processes at the same time. A HT
processor can only run two threads from the same process.
This is incorrect. HT processors don't care where the threads come
from; it is possible to run
RW writes:
But what would be the point, that's slower than running with HT turned-off.
Not necessarily. It depends on a lot of things.
It any case, nobody is forced to run with HT and SMP enabled.
--
Anthony
___
freebsd-questions@freebsd.org
.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Sun, 27 Mar 2005 20:04:16 +0200
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
Right. Thats what I said. You'll killl your networking.
Beyond a certain network load, you have
your money. If you don't need much, or you are spending someone
else's money, then everything is moot. Just use whats cool.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Sun, 27 Mar 2005 20:01:57 +0200
Subject: Re: hyper threading.
[EMAIL
[EMAIL PROTECTED] writes:
Polling is simply unecessary in most cases. You could get
better performance using an em driver and setting max
ints to whatever is optimal for your system. Polling adds
latency and over head for no good reason.
Polling often provides better performance, at the
I have 3,4ghz ht processor and freebsd shows up only one processors. I
suppose it should show two in ht models? so, GENERIC kernel doesn't
support it? but should I add to kernel config to enable it? by reading
config examples I think this should be enough:
options SMP
but is it all I need?
Perttu Laine writes:
I have 3,4ghz ht processor and freebsd shows up only one processors. I
suppose it should show two in ht models? so, GENERIC kernel doesn't
support it? but should I add to kernel config to enable it? by reading
config examples I think this should be enough:
options SMP
+0100
Subject: Re: hyper threading.
Perttu Laine writes:
I have 3,4ghz ht processor and freebsd shows up only one processors. I
suppose it should show two in ht models? so, GENERIC kernel doesn't
support it? but should I add to kernel config to enable it? by reading
config examples I think this should
Sent: Sat, 26 Mar 2005 19:28:11 +0100
Subject: Re: hyper threading.
Perttu Laine writes:
I have 3,4ghz ht processor and freebsd shows up only one processors. I
suppose it should show two in ht models? so, GENERIC kernel doesn't
support it? but should I add to kernel config to enable
-questions@freebsd.org
Sent: Sat, 26 Mar 2005 13:49:53 -0600
Subject: Re: hyper threading.
[EMAIL PROTECTED] wrote:
This is the kind of disinformation I have been
referring to
You'll get much better performance with 1 processor in
UP mode. I suggest you do some testing.
-Original Message
[EMAIL PROTECTED] writes:
You'll get much better performance with 1 processor in
UP mode. I suggest you do some testing.
Where can I see the results of your own exhaustive tests?
The purpose of hyperthreading is to keep all hardware on the
microprocessor working. Many instructions use only
[EMAIL PROTECTED] writes:
I am offerring the correct information. Turning on SMP on
an HT machine will kill the systems performance much
more than hyperthreading will gain.
Why?
I've explained why hyperthreading can provide a modest gain in
performance. Now explain to me why it would not.
from that.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Sat, 26 Mar 2005 22:06:38 +0100
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
You'll get much better performance with 1 processor in
UP mode. I suggest you do some
[EMAIL PROTECTED] writes:
Yes, the theory is very nice; you've done a nice
job reading Intel's marketing garb.
I haven't read their marketing materials. I'm simply going by the
technical descriptions I've read of the architecture.
However if you don't have a specific hyperthreading-aware
On Sat, Mar 26, 2005 at 11:45:21PM +0100, Anthony Atkielski wrote:
Where can I see the measurements?
Here are some measurements. A few weeks ago I ran Unixbench 4.1.0
(/usr/ports/benchmarks/unixbench) on a P4 2.8GHz with and without
hyperthreading enabled. I note a slight difference in the 10
Paul A. Hoadley wrote:
On Sat, Mar 26, 2005 at 11:45:21PM +0100, Anthony Atkielski wrote:
Where can I see the measurements?
Here are some measurements. A few weeks ago I ran Unixbench 4.1.0
(/usr/ports/benchmarks/unixbench) on a P4 2.8GHz with and without
hyperthreading enabled. I
Hello,
However even then this is not a good test of HT - the point of HT is to
improve throughput in multi thread workloads and the benchmark suite is
basically single thread.What would be more interesting would be to
run a test with a constant background load also running.In theory
Hello,
On Sat, Mar 26, 2005 at 03:54:06PM -0800, John Pettitt wrote:
Paul A. Hoadley wrote:
I note a slight difference in the 10 minute load average in favour
of the uniprocessor run (0.00 vs 0.10 in the hyperthreading run),
though I doubt this alone could account for a 15% difference in
-questions@freebsd.org
Sent: Sun, 27 Mar 2005 09:53:25 +0930
Subject: Re: hyper threading.
Hello,
On Sat, Mar 26, 2005 at 03:54:06PM -0800, John Pettitt wrote:
Paul A. Hoadley wrote:
I note a slight difference in the 10 minute load average in favour
of the uniprocessor run (0.00 vs 0.10
and white.
-Original Message-
From: Anthony Atkielski [EMAIL PROTECTED]
To: freebsd-questions@freebsd.org
Sent: Sat, 26 Mar 2005 23:45:21 +0100
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
Yes, the theory is very nice; you've done a nice
job reading Intel's marketing garb.
I
, 26 Mar 2005 23:45:21 +0100
Subject: Re: hyper threading.
[EMAIL PROTECTED] writes:
Yes, the theory is very nice; you've done a nice
job reading Intel's marketing garb.
I haven't read their marketing materials. I'm simply going by the
technical descriptions I've read of the architecture
: freebsd-questions@freebsd.org
Sent: Sat, 26 Mar 2005 17:23:40 -0800
Subject: Re: hyper threading.
Well you've proven than if you pick your benchmark you can get the
result you want.
So what that says it that the kernel network code doesn't get any
benefit from HT - given that HT is supposed to benefit
]
To: [EMAIL PROTECTED]
Cc: freebsd-questions@freebsd.org
Sent: Sat, 26 Mar 2005 17:23:40 -0800
Subject: Re: hyper threading.
Well you've proven than if you pick your benchmark you can get the
result you want.
So what that says it that the kernel network code doesn't get any
benefit from HT
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