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    SubjectRe: What is the limit size of tmpfs /dev/shm ?
    Hugh Dickins wrote:
    > On Wed, 6 Feb 2008, H. Peter Anvin wrote:
    >> That sounds like a problem in our overall swap handling, not specifically in
    >> tmpfs. Now, I can't say anything concrete about heavy swap conditions, but in
    >> light swap conditions I have measured a 20x performance improvement(!) over
    >> ext3 on real workloads.
    >
    > Wow, I'm surprised. I suppose I do jump to thinking of heavy swapping
    > when light swapping won't be so bad; but even so, 20x ext3 astonishes
    > me - ext3 wouldn't be anyone's choice for fastest, but even so...
    >
    > I certainly guess too much and measure too little:
    > is there a useful test you could point me to? TIA
    >

    The specific application was this:

    - extract a kernel tarball
    - "make distclean"
    - cp -al the resulting tree
    - apply a patch to each tree
    - do a diff between the trees
    - delete all files

    ... repeat something like 20,000 times.

    -hpa


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