[H-GEN] Poor performance of squid-2.5 on Redhat 7.2 compared to Solaris 8 on x86

[Robert Brockway]

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On Thu, 21 Feb 2002 ben.carlyle at invensys.com wrote:

> During my short stint at the TAB of Queensland we had a curious issue with 
> bet processing machines. We had started bringing in new pentiums to 
> replace 486 machines that had done the job before. I didn't see the issue 
> through to completion, but I was able to prove that it was related to the 
> performance of IO through the comms card used. The card was an ISA card, 
> and although the new machines supported ISA it was done through some 
> quirky PCI-ISA mapping on the board. It appeared that the drivers or 
> hardware that handled this was what reduced the processing power of the 
> pentium to about 1/10th the performance of the little 486s with 
> althogether inferiour specs.

I have seen this before.

As we all know, PCI is 33Mhz, 66Mhz, etc.  Well standard (as specified) 
ISA is 8Mhz.  But by the time that the ISA bus as on its last legs, around
the time of the end of the 486 the bus speed had been pushed up, in some
cases, as far as 20Mhz to keep up with other system components.

In contrast, the ISA buses seen on pentium class machines were legacy
devices only, so they were normally operating at the standard 8Mhz. 
Motherboard manufacturers saw no reason to try to optimise the ISA bus on
the board at all.  As a result it is common to see ISA cards get better
performance on a 486 than on a Pentium class machine.  Go figure :)  The
final 486 boxesn (like the DX4-100) were really solid machines that really
did compete with the Pentiums of the time).

Of course as soon as you go to PCI the pentiums beat the pants off the
486s :)
Rob

-- Robert Brockway B.Sc. email: robert at timetraveller.org  ICQ: 104781119
   Linux counter project ID #16440 (http://counter.li.org)
   blake: up 42 days, 11:55, 16 users,  load average: 2.12, 1.87, 1.42
   "The earth is but one country and mankind its citizens" -Baha'u'llah


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