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    SubjectRe: xmm2 - monitor Linux MM active/inactive lists graphically
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    Linus Torvalds <torvalds@transmeta.com> writes:

    > On 25 Oct 2001, Zlatko Calusic wrote:
    > >
    > > Sure. Output of 'vmstat 1' follows:
    > >
    > > 1 0 0 0 254552 5120 183476 0 0 12 24 178 438 2 37 60
    > > 0 1 0 0 137296 5232 297760 0 0 4 5284 195 440 3 43 54
    > > 1 0 0 0 126520 5244 308260 0 0 0 10588 215 230 0 3 96
    > > 0 2 0 0 117488 5252 317064 0 0 0 8796 176 139 1 3 96
    > > 0 2 0 0 107556 5264 326744 0 0 0 9704 174 78 0 3 97
    >
    > This does not look like a VM issue at all - at this point you're already
    > getting only 10MB/s, yet the VM isn't even involved (there's definitely no
    > VM pressure here).

    That's true, I'll admit. Anyway, -ac kernels don't have the problem,
    and I was misleaded by the fact that only VM implementation differs in
    those two branches (at least I think so).

    >
    > > Notice how there's planty of RAM. I'm writing sequentially to a file
    > > on the ext2 filesystem. The disk I'm writing on is a 7200rpm IDE,
    > > capable of ~ 22 MB/s and I'm still getting only ~ 9 MB/s. Weird!
    >
    > Are you sure you haven't lost some DMA setting or something?
    >

    No. Setup is fine. I wouldn't make such a mistake. :)
    If the disk were in some PIO mode, CPU usage would be much higher, but
    it isn't.

    This all definitely looks like a problem either in the bdflush daemon,
    or request queue/elevator, but unfortunately I don't have enough
    knowledge of that areas to pinpoint it more precisely.
    --
    Zlatko
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