Re: Performance on the long run

From: Robert Harley (Robert.Harley@inria.fr)
Date: Fri Mar 10 2000 - 20:14:55 MET

  • Next message: Dries Schellekens: "weird"

    Patrick Vigneras wrote:
    >Then i guess i must wrongly interpret the meaning of "iteration" in this
    >case. What surprised me was that both the rate and the number of
    >iterations between distinguished points was nearly constant.

    Let me describe what the numbers mean in a bit of detail. Hopefully
    this will dispel any confusion. Here is a example that my Linux
    machine found this afternoon:

      Distinguished point found at: Fri Mar 10 13:09:25 2000
      ECC-L0|Unix64|1.1.0|
      ECC-L1|FE33138028BDBB8BF3FA636009E|EB6ABB69DA9ED7E5770143F57BC|
      ECC-L2|Robert.Harley@inria.fr|
      ECC-L3|00004349946E|
      ECC-L4|corton|
      Iterations used = 1128895598.
      Total iterations = 330599254848.
      Rate = 228487 per second.

    The "Iterations used" line reports the number of iterations that led
    to this distinguished point (note: it is correct even if you stop and
    restart the process since it is saved in the saved state).

    But remember that there are PARAL chains of iterations running in
    parallel (by default PARAL = 32). The number of iterations reported
    could be quite large, which would mean that the chain of iterations
    that led to this distinguished point had been running for a long
    time. But some other chain might have found a point just minutes
    before! In fact one did:

      Distinguished point found at: Fri Mar 10 13:02:36 2000
      ECC-L0|Unix64|1.1.0|
      ECC-L1|F6AC92BF7F3ED78E2E3A17B8899|429A61E46093371A73F1BFD7324|
      ECC-L2|Robert.Harley@inria.fr|
      ECC-L3|000021C8900D|
      ECC-L4|corton|
      Iterations used = 566792205.
      Total iterations = 330509000544.
      Rate = 228487 per second.

    So the "Iterations used" is only indirectly related to the amount of
    time that separates distinguished points.

    The "Total iterations" lines show the number of iterations for this
    process since it started up. By subtracting the two values you can
    see that it did 90254304 iterations between 13:02 and 13:09, much less
    than the 1.13 billion used for the later point.

    Finally the "Rate" is calculated from the CPU time consumed by this
    process since it started and from the total number of iterations (note
    that wall-clock time is not used).

    Hope this helps,
      Rob.

    This archive was generated by hypermail 2b29 : Sat Mar 11 2000 - 00:27:01 MET