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Conference 7.286::fddi

Title:FDDI - The Next Generation
Moderator:NETCAD::STEFANI
Created:Thu Apr 27 1989
Last Modified:Thu Jun 05 1997
Last Successful Update:Fri Jun 06 1997
Number of topics:2259
Total number of notes:8590

1120.0. "FDDI performance ??" by TAV02::KATZAV () Wed Oct 20 1993 16:18

    
    A customer asked if we have FDDI performance in Specint92for
    1Mbytes/sec ?
    He got from another vendor the figure of cpu consumption of 4Specin92
    to transfer 1Mbyte/sec via FDDI ??
    
    Thanks,
    Shimon.
    
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1120.1KONING::KONINGPaul Koning, B-16504Thu Oct 21 1993 11:195
There is no such thing.  SpecInt measures application compute performance.
It doesn't apply to networking performance.  Your customer has been given
nonsensical information by the other vendor.

	paul
1120.2CPU utilizationTAV02::KATZAVThu Oct 21 1993 16:328
    
    Maybe the other vendor took the CPU consumption and translated it
    to the spec as a percent of the total spec?
    What are the cpu utilization on DEC3000-600 with FDDI to transfer
    1Mbyte/sec ??
    
    Thanks,
    Shimon.
1120.3NETRIX::thomasThe Code WarriorThu Oct 21 1993 16:556
Using what protocol?  From the file system or generated data?  Aligned
or unaligned data?  To what type of system?

Aside from that, since (at least under OSF/1) a 3000/500 can almost 
saturate a FDDI ring with about 30-40% CPU left over, I would expect
a that 3000/600 should be able to even better than that.
1120.4KONING::KONINGPaul Koning, B-16504Fri Oct 22 1993 13:2112
Re .2: even so, that makes no sense.  All that's being displayed is a great
ignorance of benchmarking and performance measurement.

"specmark" is a number obtained from executing a very specific set of tests
in a very specific environment.  It CANNOT be applied to any other test, 
especially not to tests of a very different kind, such as network performance.

It would make as much (or rather, as little) sense to ask "what is the capacity
of your system disk, expressed in specmarks", or "how big is your memory,
expressed in specmarks".  (Or "how far is it to Cleveland, expressed in pounds")

	paul
1120.5to explain Paul's responseMUDDY::WATERSFri Oct 22 1993 13:5319
>    Maybe the other vendor took the CPU consumption and translated it
>    to the spec as a percent of the total spec?

    Yes, you can translate percentage CPU utilization for 1 MB/s FDDI (using
    specific protcols/applications) into SPECint92 *of a specific computer
    model*.  What you've done is to take a fairly clear performance metric,

	percentage CPU utilization for 1 MB/s of xxx transfer over FDDI
	on computer model yyy	[where xxx is the network application]

    and turn it into a less clear metric

	SPECint92 CPU utilization for 1 MB/s of xxx transfer over FDDI
	on computer model yyy whose peak SPECint92 was zzz on date dd-mmm-yy

    The new metric takes more lines to explain than the old one; it relies
    on more variables (both network software version *and* SPEC benchmark
    version and compiler version).  The new metric should be avoided; the
    old percentage-CPU metric has more direct meaning.
1120.6FDDI white paperTAV02::KATZAVFri Oct 22 1993 14:166
    
    Got the message.
    
    Any white paper that has performance numbers in it ??
    
    -Shimon.
1120.7FDDI NIC White Paper in note 1070MUDDY::WATERSFri Oct 22 1993 14:521
    Is note 1070 any help?
1120.8KONING::KONINGPaul Koning, B-16504Fri Oct 22 1993 18:5211
Re .5: I disagree, since SpecInt is a composite of several test programs,
and the ratio of the running speeds of program x doesn't necessarily match
the specint ratio.  (This is because of the way the system architecture
affects a particular program, the way the compiler optimizes that particular
program, etc.)

Therefore the specint number doesn't predict the performance of any of
the programs in the test suite.  It DEFINITELY does not predict the performance
of any other program.

	paul
1120.9MUDDY::WATERSSun Oct 24 1993 12:097
>Therefore the specint number doesn't predict the performance of any of
>the programs in the test suite.

    No, you don't disagree with me.  We're both saying that SPECint92
    predicts nothing; it only measures itself (a benchmark suite).  I did
    not claim that SPECint92 does anything other than measuring its own
    performance on one machine.