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Date:      Thu, 02 Aug 2001 11:34:56 -0400
From:      Matthew Hagerty <mhagerty@voyager.net>
To:        Hassan Halta <hassan@cs.earlham.edu>, <freebsd-questions@FreeBSD.ORG>
Subject:   Re: 2 CPUs under FreeBSD
Message-ID:  <5.0.2.1.2.20010802111855.0184f060@pop.voyager.net>
In-Reply-To: <20010802005047.T29027-100000@quark.cs.earlham.edu>

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At 12:53 AM 8/2/2001 -0500, Hassan Halta wrote:
>Hi,
>
>We are running FreeBSD 4.3 Release, and we have 2 CPUs in our server. We
>configured the Kernel to realize the existence of the 2nd CPU, and
>everything seems to be working fine. However we have the problem with TOP.
>It always shows either CPU to be using 0.00%, even when the hard drive is
>hammered with some heavy processes, it's always 0.00%.
>
>I was wondering what you guys can advise in this matter, or what are the
>steps to do the whole thing right.
>
>Thanks,
>Hassan

Having two CPUs in hardware and supported by the OS does not mean 
applications will necessarily take advantage of them.  An application has 
to be written in such a way that the OS can execute it on multiple 
processors if available.  I would say that TOP is *not* such and 
application, and you did not mention what you were running on this machine.

Also, heavy disk I/O is not an indicator of heavy load on your server, it 
is an indication that you need more memory and a better disk subsystem, 
i.e. SCSI-160, a RAID, or simply more servers to even the disk 
load.  During heavy disk I/O the CPU will more likely be 99.9% idle since 
it is waiting for the slow disk to finish.

Something CPU intensive would be calculating the next prime number or 
processing weather patterns, etc.  Most Internet based serving, i.e. HTTP, 
SMTP, FTP, etc. is *not* processor intensive, so you should not see much 
CPU load.  Internet services are more memory, bandwidth, and disk 
intensive, so that is where you should be upgrading your servers.  Also, 
RDBMS systems *can* be processor intensive, but only if they are doing big 
complex queries.  Otherwise, for database backends to web sites, etc. it is 
still mostly disk I/O because the queries being executed are simple 
lookups, updates, adds, and deletes.

Faster drives and more memory will go a long way to making your server faster.


Matthew


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