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    SubjectRe: pdflush question...
    On Wed, 2003-09-03 at 05:24, Daniel Blueman wrote:
    > Is it worth having a kernel config option to vary the number of 'pdflush'
    > kernel threads?

    I suspect no.

    > For embedded, systems with no swap and maybe uniproc (?), perhaps one
    > pdflush kthread would do?

    Yes. Definitely. In fact, I think that, for all systems, the initial
    default should perhaps be one.

    But note that the reason for n>1 pdflush threads is neither swap or
    processor related. The multiple threads can keep multiple block devices
    busy, since one thread blocking on I/O will not affect another one.

    I guess the real test would be to set MIN_PDFLUSH_THREADS to one and see
    if one is enough for the average machines. If the number quickly jumps
    to 2 or more... then we know its a bad idea.

    > Perhaps more generally, the number could be linked to the number of
    > processors and/or swap devices or spindles- this would eliminate having to configure
    > it, and improve downward and upward scaling, perhaps?

    Number of spindles, yes. But how do we know that? And its just the
    number of busy spindles, really.

    I say we drop down to one.

    Robert Love

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