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Re: Emulating vintage computers

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antispam@fricas.org (Waldek Hebisch) writes:
> I wonder how you get those numbers?  Basicaly processor speed is clock
> frequency times with of processor time utilization of that.

from original post:

(benchmarks are number of program iterations compared to reference
platform, not actual instruction count)

...

industry standard MIPS benchmark had been number of program iterations
compared to one of the reference platforms (370/158-3 assumed to be one
MIPS) ... not actual instruction count ... sort of normalizes across
large number of different architectures.

consideration has been increasing processor rates w/o corresponding
improvement in memory latency. For instance IBM documentation claimed
that half of the per processor throughput increase going from z10 to
z196 was the introduction of some out-of-order execution (attempting
some compensation for cache miss and memory latency, features that have
been in other platforms for decades).

z10, 64 processors, 30BIPS (469MIPS/proc), Feb2008
z196, 80 processors, 50BIPS (625MIPS/proc), Jul2010

aka half of the 469MIPS/proc to 625MIPS/proc ... (625-469)/2; aka 78MIPS
per processor from Z10 to z196 due to some out-of-order execution.

There have been some pubs about recent memory latency when measured in
terms of processor clock cycles is similar to 60s disk latency when
measured in terms of 60s processor clock cycles.

trivia: early 80s, I wrote a tome that disk relative system throughput
had declined by an order of magnitude since mid-60 (i.e. disks got 3-5
faster while systems got 40-50 times faster). Disk division executive
took exception and assigned the performance group to refute the
claims. After a few weeks they came back and effectively said I had
slightly understated the problem. They then respun the analysis to
configuring disks to increase system throughput (16Aug1984, SHARE 63,
B874).

trivia2: a litle over decade ago, I was asked to track down the decision
to add virtual memory to all IBM 370s. I found staff member to executive
making the decision. Basically MVT storage management was so bad that
region sizes had to be specified four times larger than used. As a
result a typical 1mbyte, 370/165 only ran four concurrent regions at a
time, insufficient to keep 165 busy and justified.  Going to MVT in
16mbyte virtual memory (VS2/SVS) allowed increasing the number of
regsions by factor of four times (caped at 15 because of 4bit storage
protect keys) with little or no paging ... similar to running MVT in a
CP67 16mbyte virtual machine (aka increasing overlapped execution while
waiting on disk I/O, and our-of-order execution increasing overlapped
execution while waiting on memory).

-- 
virtualization experience starting Jan1968, online at home since Mar1970

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  Emulating vintage computers Lars Poulsen <lars@beagle-ears.com> - 2024-09-26 10:12 -0700
    Re: Emulating vintage computers David Wade <g4ugm@dave.invalid> - 2024-09-26 18:44 +0100
      Re: Emulating vintage computers "Kurt Weiske" <kurt.weiske@realitycheckbbs.org.remove-nnv-this> - 2024-09-27 07:43 -0700
        Re: Emulating vintage computers D <noreply@mixmin.net> - 2024-09-27 17:00 +0100
    Re: Emulating vintage computers Lynn Wheeler <lynn@garlic.com> - 2024-09-26 08:39 -1000
      Re: Emulating vintage computers antispam@fricas.org (Waldek Hebisch) - 2024-09-28 14:30 +0000
        Re: Emulating vintage computers Lynn Wheeler <lynn@garlic.com> - 2024-09-28 13:02 -1000
          Re: Emulating vintage computers Lynn Wheeler <lynn@garlic.com> - 2024-09-28 14:01 -1000
            Re: Emulating vintage computers John Ames <commodorejohn@gmail.com> - 2024-09-30 11:04 -0700
              Re: Emulating vintage computers drb@ihatespam.msu.edu (Dennis Boone) - 2024-10-01 00:24 +0000
          Re: Emulating vintage computers antispam@fricas.org (Waldek Hebisch) - 2024-09-30 03:43 +0000
            Re: Emulating vintage computers Lawrence D'Oliveiro <ldo@nz.invalid> - 2024-09-30 03:50 +0000
              Re: Emulating vintage computers antispam@fricas.org (Waldek Hebisch) - 2024-09-30 10:37 +0000
    Re: Emulating vintage computers Bill Findlay <findlaybill@blueyonder.co.uk> - 2024-09-27 23:59 +0100
      Re: Emulating vintage computers geodandw <geodandw@gmail.com> - 2024-09-28 01:43 -0400
    Re: Emulating vintage computers antispam@fricas.org (Waldek Hebisch) - 2024-09-28 15:18 +0000

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