lkml.org 
[lkml]   [1999]   [Nov]   [3]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: Linux Buffer Cache Does Not Support Mirroring

The less time spent holding sleep locks the better. calling lots of
redundant sync code to release a bndle of IO requests is dumb if you can
release them in batch. NT uses something called MDL lists that allow
multiple requests for a file to be transacted accross several processors
at the same time, reducing latency.

Jeff

Rik van Riel wrote:
>
> On Tue, 2 Nov 1999, Jeff V. Merkey wrote:
>
> > The Statement relates to increased parallelism on FS code paths
> > (they don't have to block), and allows multiple I/O requests to be
> > handled as a "bundle" rather than one at a time. The benefit is
> > immediately obvious since less time is spent calling semaphore and
> > sync code in the kernel (shorter code paths, less rendudant
>
> You seem to make a somewhat outdated optimisation here, offering
> up I/O bandwidth (disk time) to save on CPU time. With the way
> the processor/memory/disk speed 'balance' is going, I don't know
> if that would be a tenable situation in the future.
>
> The "I'm idle now, gimme work" idea is a very sane idea when
> processors and memory are outrunning disk speed by many orders
> of magnitude (and the gap is widening on a monthly basis).
>
> Of course, it doesn't make much sense to give a disk it's block
> when we've only got one page ready to write out, but once we
> have 64 or 128 kB, it all starts to make sense.
>
> regards,
>
> Rik -- There's no seek time like idle time
> --
> The Internet is not a network of computers. It is a network
> of people. That is its real strength.

-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.rutgers.edu
Please read the FAQ at http://www.tux.org/lkml/

\
 
 \ /
  Last update: 2005-03-22 13:54    [W:0.071 / U:0.472 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site