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    SubjectRe: Memory upgrade: not faster / nfs
    Date
    In linux.dev.kernel, article <"sim0s4.fzi.178:25.10.96.16.26.14"@fzi.de>,
    Christoph Trautwein <trautw@fzi.de> writes:
    > ------- =_aaaaaaaaaa0
    > Content-Type: text/plain; charset="us-ascii"
    >
    > Problem:
    > ! NFS is a filesystem. Filesystems are not cached.
    > ! The only thing that's cached in UN*X are block
    > ! devices. This is the wrong place to cache.
    >
    This is true for UN*X in general, I'd say, but NOT for Linux 2.0.

    -rwxr-xr-x 1 smurf user 412521 Feb 21 1996 XXX.eps

    work:/uneu/urlichs 1243$ time cat XXX.eps >/dev/null
    0.01user 0.22system 0:02.07elapsed 11%CPU (0avgtext+0avgdata 0maxresident)k
    0inputs+0outputs (0major+0minor)pagefaults 0swaps

    work:/uneu/urlichs 1244$ time cat XXX.eps >/dev/null
    0.02user 0.04system 0:00.08elapsed 75%CPU (0avgtext+0avgdata 0maxresident)k
    0inputs+0outputs (0major+0minor)pagefaults 0swaps

    YOU tell me how to pull 5 MBytes/sec over a 10 MBit/sec Ethernet if you
    don't believe me. :-)

    > Is it correct how I see these things?
    No.

    > Why are filesystems not buffered?
    Because initially, there were no file systems without a corresponding block
    device, and buffering the whole device means fewer numbers to store. Plus,
    the metadata on a file system obviously can't be cached in the file cache
    because there's no file associated with them.

    > Is there a nfs implementation that does buffering?
    Yes. See above.

    --
    But we've only fondled the surface of that subject.
    --Virginia Masters [of Master & Johnson]
    --
    Matthias Urlichs \ noris network GmbH / Xlink-POP Nürnberg
    Schleiermacherstraße 12 \ Linux+Internet / EMail: urlichs@noris.de
    90491 Nürnberg (Germany) \ Consulting+Programming+Networking+etc'ing
    PGP: 1024/4F578875 1B 89 E2 1C 43 EA 80 44 15 D2 29 CF C6 C7 E0 DE
    Click <A HREF="http://info.noris.de/~smurf/finger">here</A>. 42

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