CPU usage of httpd+slowcgi

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CPU usage of httpd+slowcgi

Kihaguru Gathura-2
Hi,

Which of the following legacy CPU types is best suited for very busy web
server httpd+slowcgi

Niagara CPU Such as T2 - More parallel Threads and Low power per single
thread
Sparc64 CPU such as VI, VII - Fewer threads but more computing power per
thread.

How is multithreading utilization of httpd+slowcgi like?

Kind regards,

Kihaguru.
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Re: CPU usage of httpd+slowcgi

Stuart Henderson
On 2020-07-24, Kihaguru Gathura <[hidden email]> wrote:

> Hi,
>
> Which of the following legacy CPU types is best suited for very busy web
> server httpd+slowcgi
>
> Niagara CPU Such as T2 - More parallel Threads and Low power per single
> thread
> Sparc64 CPU such as VI, VII - Fewer threads but more computing power per
> thread.
>
> How is multithreading utilization of httpd+slowcgi like?

Like most of the base system, httpd and slowcgi are not multithreaded,
also OpenBSD's scheduler doesn't really know about multithread cpus
(and even for full cpu cores, beyond a handful of cores OpenBSD doesn't
cope all that well).

Generally fewer faster cores is the way to go for OpenBSD.


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Re: CPU usage of httpd+slowcgi

Stuart Henderson
Replying back on-list, I don't do support-type mails off-list, and other
people know more about sparc64 hardware than me.

On 2020/07/26 22:38, Kihaguru Gathura wrote:
> Hi Stuart,
>
> For legacy, single-core CPU's such as Sparc64 V.
> Would OpenBSD cope well with more number of CPU's or less as in previous case?
>
> Example.
>
> 2 CPU's (primepower 250) -> 4 CPU's (PrimePower 450) -> 8 CPU's(PrimePower 650) -> 16 CPU's
> (PrimePower 850) -> 32 CPU's (Primepower 1500)

It depends on the workload. I'd have thought for most things the max
really usable at the moment is probably somewhere in the region of 4-8
cpu cores before kernel locking gets in the way too much.

FWIW sparc64 ports builds are now done on T4 and they're really fast.
I think (but am not 100% sure) that this is carved into ldoms so the
number of cores visible to each OpenBSD instance is limited (so
contention between cores in the kernel is also limited).

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Re: CPU usage of httpd+slowcgi

Claudio Jeker
On Mon, Jul 27, 2020 at 02:54:25PM +0100, Stuart Henderson wrote:

> Replying back on-list, I don't do support-type mails off-list, and other
> people know more about sparc64 hardware than me.
>
> On 2020/07/26 22:38, Kihaguru Gathura wrote:
> > Hi Stuart,
> >
> > For legacy, single-core CPU's such as Sparc64 V.
> > Would OpenBSD cope well with more number of CPU's or less as in previous case?
> >
> > Example.
> >
> > 2 CPU's (primepower 250) -> 4 CPU's (PrimePower 450) -> 8 CPU's(PrimePower 650) -> 16 CPU's
> > (PrimePower 850) -> 32 CPU's (Primepower 1500)
>
> It depends on the workload. I'd have thought for most things the max
> really usable at the moment is probably somewhere in the region of 4-8
> cpu cores before kernel locking gets in the way too much.
>
> FWIW sparc64 ports builds are now done on T4 and they're really fast.
> I think (but am not 100% sure) that this is carved into ldoms so the
> number of cores visible to each OpenBSD instance is limited (so
> contention between cores in the kernel is also limited).

The primepower 250 are decent and IIRC you can get dual core SPARC64-VI
CPUs for those. They use a fair amount of power. The bigger irons are fun
but honestly the weight and power consumption is just not worth it.
A primepower 250 is compareable with a fast v215. At least that is my
experience.

Better to look for an M3000 or M4000 or as suggested for a T4-1. Also make
sure you get good CPUs in them (esp. the M4000 comes with a few options).

--
:wq Claudio

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Re: CPU usage of httpd+slowcgi

Theo de Raadt-2
> Better to look for an M3000 or M4000 or as suggested for a T4-1

M3000 don't work.  The firmware locks up very badly.

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Re: CPU usage of httpd+slowcgi

Jordan Geoghegan-3
In reply to this post by Kihaguru Gathura-2


On 2020-07-24 03:16, Kihaguru Gathura wrote:

> Hi,
>
> Which of the following legacy CPU types is best suited for very busy web
> server httpd+slowcgi
>
> Niagara CPU Such as T2 - More parallel Threads and Low power per single
> thread
> Sparc64 CPU such as VI, VII - Fewer threads but more computing power per
> thread.
>
> How is multithreading utilization of httpd+slowcgi like?
>
> Kind regards,
>
> Kihaguru.

Hi  Kihaguru,

As with any computer, newer tends to be better with Moore's Law and all
that. On sparc64 most of the logical cores that are shown are really
just SMT pretending to be a bunch of cores. I have one machine that
claims 128 cores, but in reality, its just 16 cores with 8-way SMT.
sparc64 isn't renowned for its single core execution speed, so the
faster the better in that regard.

In my experience with running OpenBSD on sparc64, the kernel biglock or
crypto became a bottleneck before other things did. (I've used T3 and T4
machines fairly extensively with OpenBSD). I've found that disk
activity, networking and/or TLS would bottleneck before httpd became a
bottleneck when I was running sparc64 web servers in production. If you
are running very heavy scripts/programs with slowcgi, then you're
results may be different.

Things have likely improved dramatically in the past year or two with
all the work done on removing the biglock, but the moral of the story
remains, fewer, faster cores are likely to produce superior performance
to numerous low power cores.

Regards,

Jordan

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Re: CPU usage of httpd+slowcgi

Alceu Rodrigues de Freitas Junior
Hi Kihaguru,

Oh, well, didn't see anybody asking, so... why are you guys still using
a CGI if so much processing power is required?

Basically anything will perform better nowadays, so unless the code is
really complicated, you're looking for a solution at the wrong place.

Em 27/07/2020 14:52, Jordan Geoghegan escreveu:

>
>
> On 2020-07-24 03:16, Kihaguru Gathura wrote:
>> Hi,
>>
>> Which of the following legacy CPU types is best suited for very busy web
>> server httpd+slowcgi
>>
>> Niagara CPU Such as T2 - More parallel Threads and Low power per single
>> thread
>> Sparc64 CPU such as VI, VII - Fewer threads but more computing power per
>> thread.
>>
>> How is multithreading utilization of httpd+slowcgi like?
>>
>> Kind regards,
>>
>> Kihaguru.
>
> Hi  Kihaguru,
>
> As with any computer, newer tends to be better with Moore's Law and all
> that. On sparc64 most of the logical cores that are shown are really
> just SMT pretending to be a bunch of cores. I have one machine that
> claims 128 cores, but in reality, its just 16 cores with 8-way SMT.
> sparc64 isn't renowned for its single core execution speed, so the
> faster the better in that regard.
>
> In my experience with running OpenBSD on sparc64, the kernel biglock or
> crypto became a bottleneck before other things did. (I've used T3 and T4
> machines fairly extensively with OpenBSD). I've found that disk
> activity, networking and/or TLS would bottleneck before httpd became a
> bottleneck when I was running sparc64 web servers in production. If you
> are running very heavy scripts/programs with slowcgi, then you're
> results may be different.
>
> Things have likely improved dramatically in the past year or two with
> all the work done on removing the biglock, but the moral of the story
> remains, fewer, faster cores are likely to produce superior performance
> to numerous low power cores.
>
> Regards,
>
> Jordan
>