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    SubjectRe: [BENCHMARK] ext3, reiser, jfs, xfs effect on contest
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    On Saturday 01 Feb 2003 6:29 am, Hans Reiser wrote:
    > Andrew Morton wrote:
    > >Hans Reiser <reiser@namesys.com> wrote:
    > >>compilation is not an effective benchmark anymore, not for Linux
    > >>filesystems, they are all just too fast (or is it that the compilers are
    > >>too slow?....)
    > >
    > >The point of this test is to measure interactions, and fairness.
    > >
    > >It answers the question "how much impact does heavy filesystem I/O have
    > > upon other system activity?".
    > >
    > >The "other system activity" in this test is a kernel compile. That is a
    > >fairly reasonable metric, because it is sensitive to latencies in
    > > servicing reads and it is sensitive to inappropriate page replacement
    > > decisions.
    > >
    > >A more appropriate foreground load might be opening a word processor and
    > >composing a short letter to Aunt Nellie, but that's harder to automate.
    > > We expect that reduced kernel compilation time will correlate with
    > > lower-latency letter writing.
    >
    > I think the result of the test was that this was not a compelling reason
    > for users selecting a particular one of the filesystems because they all
    > did well enough at it. Perhaps because of your code.:)
    >
    > However, it is rather interesting for all the reasons you mention.
    > There is indeed a tendency for benchmarks to discount the importance of
    > latency, and this benchmark does not do that, which is good. It is
    > annoying to be unable to work while a big tar is running in the
    > background, but few benchmarks capture that.
    >
    > We should test reiser4 against this next month, it would be
    > interesting. (It seems we finally fixed the Reiser4 performance problem
    > that we hit in August, and now we just need to tweak the CPU usage a bit
    > and we'll have something performing pretty decently in our next
    > release....)

    Actually the most "felt" of these loads is io_load and based on these results:
    io_load:
    Kernel [runs] Time CPU% Loads LCPU% Ratio
    2559ext3 3 109 68.8 4 10.1 1.40
    2559jfs 3 138 54.3 11 13.8 1.77
    2559reiser 3 98 76.5 2 9.2 1.24
    2559xfs 3 124 60.5 6 8.0 1.57

    I'd say barring any concern about throughput which this doesnt claim to
    measure accurately reiserfs causes the least slowdown of the system ;-)

    I do have one more load which may be useful. dbench_load continually runs
    dbench in the background. I could throw that at it also.

    Ext2 was left out for clarity because it wasn't a journalling fs but it's
    results are quite different to the journalled fss.

    Con
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