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
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'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
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
> >
[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
ssors 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
[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 principl
a long
journey.
-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 comment
om: Anthony Atkielski <[EMAIL PROTECTED]>
> To: freebsd-questions@freebsd.org
> Sent: Tue, 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.
bsd.org
Sent: Tue, 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
___
[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
http://lists.freebsd.org
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 th
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:"
___
freebsd-questions@freebsd.o
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
http://lists.freebsd.org/mailman/listinfo/freebsd
[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.
--
Ant
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:
[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 blab
e is no traffic
there are no interrupts.
So if you have 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
[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
are a much 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 Spirialitiou
d. Setting MAX_INTS 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 case
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 c
--- 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
[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 e
ersion of the OS, then you are wasting
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 20
're grasping at straws.
-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
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 mai
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
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 sam
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 archite
[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
[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 throughpu
From: 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
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 diverse user
tasks and
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 measurements.
FreeBSD 4.9 ->> Load: 38% (I put this in for fun :-)
Freebsd 5.4-Pre UP (no HT) -> L
[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 utiliz
[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
>
> Free
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
al Message-
> From: John Pettitt <[EMAIL PROTECTED]>
> 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
IL 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 - given that
ould argue both depending on what benchmark you use. You
> have to test it in the environment where you plan to use it. Because
> the answer is almost never black and white.
>
>
>
> -Original Message-
> From: Anthony Atkielski <[EMAIL PROTECTED]>
> To: freebsd
lan to use it. Because
the answer is almost never black 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
PROTECTED]>
Cc: freebsd-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 r
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% differ
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 theor
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
>hyperthreadin
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
[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
ll written code to handle it properly. FreeBSD is
a long way off 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 muc
[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.
[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
reebsd-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.
-Origi
TECTED]>
> To: freebsd-questions@freebsd.org
> 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,
05 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 it? by reading
config examples I t
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
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?
--
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