[lkml]   [1999]   [Jun]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
    SubjectRe: direct (unbufferd) disk access
    > On Mon, 28 Jun 1999 09:24:06 -0700 (PDT), Matthew Jacob
    > <> said:
    > >> On Sat, 26 Jun 1999 00:06:53 -0400, Douglas Gilbert
    > >> Given that we have clocked reasonably standard i386 hardware with fast
    > >> disks at 50 or 60 MB/sec through the filesystem, I doubt that the
    > >> indirect IO is the bottleneck in those cases.
    > > Without cache pollution?
    > Page cache pollution is a totally different issue. At 60MB/sec
    > we aren't even close to the performance levels where memory bandwidth
    > is an issue, so extra copies into the cache are irrelevant from a
    > bandwidth point of view. Of _course_ raw IO has less impact on
    > memory, but that's another point entirely.

    What I mean was: raw I/O is an application policy statement that says
    "leaving this data in the buffer cache is not what I want". You certainly
    do have some overhead in throwing stuff away if it's sitting in the buffer

    To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
    the body of a message to
    Please read the FAQ at

     \ /
      Last update: 2005-03-22 13:52    [W:0.038 / U:6.876 seconds]
    ©2003-2016 Jasper Spaans. hosted at Digital OceanAdvertise on this site