[lkml]   [2007]   [Jul]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: How can we make page replacement smarter (was: swap-prefetch)
Al Boldi wrote:
> Chris Snook wrote:

>> At best, reads can be read-ahead and cached, which is why
>> sequential swap-in sucks less. On-demand reads are as expensive as I/O
>> can get.
> Which means that it should be at least as fast as swap-out, even faster
> because write to disk is usually slower than read on modern disks. But
> linux currently shows a distinct 2x slowdown for sequential swap-in wrt
> swap-out.

That's because writes are faster than reads in moderate

The disk caches writes, allowing the OS to write a whole
bunch of data into the disk cache and the disk can optimize
the IO a bit internally.

The same optimization is not possible for reads.

Politics is the struggle between those who want to make their country
the best in the world, and those who believe it already is. Each group
calls the other unpatriotic.
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to
More majordomo info at
Please read the FAQ at

 \ /
  Last update: 2007-07-29 06:11    [W:0.046 / U:0.436 seconds]
©2003-2018 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site