The README in linux-smp-2.6.17.13 in extra has the wording "and
optimizations for dual-core CPUs".

Does optimizations mean it is better than the huge26.s for utilizing the
dual core or that the huge26.s doesn't use the second core at all?


--
Alan

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On Tue, 26 Dec 2006 12:04:04 +0000, Alan Clifford wrote:
> The README in linux-smp-2.6.17.13 in extra has the wording "and
> optimizations for dual-core CPUs".
>
> Does optimizations mean it is better than the huge26.s for utilizing the
> dual core or that the huge26.s doesn't use the second core at all?

huge26.s is not a MP kernel, so the second core will not be used with that
kernel.

-- Daniel

On Tue, 26 Dec 2006, Daniel de Kok wrote:

DdK> On Tue, 26 Dec 2006 12:04:04 +0000, Alan Clifford wrote:
DdK> > The README in linux-smp-2.6.17.13 in extra has the wording "and
DdK> > optimizations for dual-core CPUs".
DdK> >
DdK> > Does optimizations mean it is better than the huge26.s for utilizing the
DdK> > dual core or that the huge26.s doesn't use the second core at all?
DdK>
DdK> huge26.s is not a MP kernel, so the second core will not be used with that
DdK> kernel.
DdK>

I'm pleased to say that I now have two penguins at the top of the screen
at boot and cat /proc/cpuinfo confirms two cores.

I had to recompile the kernel using pentium 4. There was not an option to
choose a pentium D so I had to find out what a pentium D might be. And
then I had to reinstall the new e1000 driver in the rebuilt modules.

Overall, I have to say that this has not been a good experience, starting
at the very beginning with the (expected) need to enter the bios menus to
make the first boot device the cdrom.

I didn't buy this computer for two cores but now I've got them, will
anything actually use them? Is this done by the kernel or does software
have to do it?

--
Alan

( If replying by mail, please note that all "sardines" are canned.
There is also a password autoresponder but, unless this a very
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Alan Clifford <sardines@purse-seine.net> wrote:
> I didn't buy this computer for two cores but now I've got them, will
> anything actually use them? Is this done by the kernel or does software
> have to do it?

The kernel will allocate the two cores to different processes when there
is more than one process which need CPU at the same time. If you are
running only one application and want that single application to take full
advantage of your entire CPU you should make sure that the single
application is using more than one thread.

However, even with single threaded applications (most applications are
single threaded) your second CPU core is useful. By using the command
"top" you can see which applications are in running state, "R". Those
applications need CPU. There is also a column in top which tells which CPU
a process is using.

regards Henrik
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I've been running dual cores (although not on the same chip!) for years
now, and I have to say that while I've often found that it doesn't help
individual programs to run much faster (since, like Henrik said, most
programs are still single threaded these days) I have certainly noticed
the difference when it comes to multitasking! I'm an engineer, and I've
often got some numerical simulation or other running, and with a second
core, my machine is still usable for other things while these
simulations are running!

I think, though, that to most average users (making no implications
here about yourself!), having a dual core is really just a kind of a
show off point. For the sort of run-of-the-mill computing that most
people do, I don't think that a second processor is really necessary.

--Chad

Henrik Carlqvist wrote:
> Alan Clifford <sardines@purse-seine.net> wrote:
> > I didn't buy this computer for two cores but now I've got them, will
> > anything actually use them? Is this done by the kernel or does software
> > have to do it?
>
> The kernel will allocate the two cores to different processes when there
> is more than one process which need CPU at the same time. If you are
> running only one application and want that single application to take full
> advantage of your entire CPU you should make sure that the single
> application is using more than one thread.
>
> However, even with single threaded applications (most applications are
> single threaded) your second CPU core is useful. By using the command
> "top" you can see which applications are in running state, "R". Those
> applications need CPU. There is also a column in top which tells which CPU
> a process is using.
>
> regards Henrik
> --
> The address in the header is only to prevent spam. My real address is:
> hc8(at)uthyres.com Examples of addresses which go to spammers:
> root@variousus.net root@localhost

On Wed, 27 Dec 2006, Charles Parker wrote:

CP>
CP> I think, though, that to most average users (making no implications
CP> here about yourself!), having a dual core is really just a kind of a
CP> show off point. For the sort of run-of-the-mill computing that most
CP> people do, I don't think that a second processor is really necessary.
CP>

I think that Apache starts new processes for each connection? So as
Google and Yahoo and msn and whoever are walking my website, which they
seem to do continuously, presumably there would be some benefit.

--
Alan

( If replying by mail, please note that all "sardines" are canned.
There is also a password autoresponder but, unless this a very
old message, a "tuna" will swim right through. )

On 2006-12-28, Alan Clifford <sardines@purse-seine.net> wrote:

> I think that Apache starts new processes for each connection? So as
> Google and Yahoo and msn and whoever are walking my website, which they
> seem to do continuously, presumably there would be some benefit.

Not entirely true. Apache spawns N subprocesses to handle remote
clients, but will not exceed a given parameter in httpd.conf no
matter how many clients are trying to connect. Further, those
subprocesses stick around to handle multiple requests, possibly
from multiple clients, before dying; it's not a one-httpd-per-
client-request kind of thing. So it's more efficient with the
CPU than you make it out to be; also factor in that HTML is small,
and even with bots crawling your site the CPU hit should be
minimal. So the likeliest limiting factor for these requests will
be your bandwidth, not your CPU, in how your machine responds to
all these bots. (If they're hitting CGI programs, all this is out
the window, since those do spawn one process per request.)

--keith

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