On 07/04/2014 12:23 AM, Linus Torvalds wrote:
On Thu, Jul 3, 2014 at 11:38 AM, Raghavendra K T
<raghavendra.kt@xxxxxxxxxxxxxxxxxx> wrote:
Okay, how about something like 256MB? I would be happy to send a patch
for that change.
I'd like to see some performance numbers. I know at least Fedora uses
"readahead()" in the startup scripts, do we have any performance
numbers for that?
Also, I think 256MB is actually excessive. People still do have really
slow devices out there. USB-2 is still common, and drives that read at
15MB/s are not unusual. Do we really want to do readahead() that can
take tens of seconds (and *will* take tens of seconds sycnhronously,
because the IO requests fill up).
So I wouldn't go from 2 to 256. That seems like an excessive jump. I
was more thinking in the 4-8MB range. But even then, I think we should
always have technical reasons (ie preferably numbers) for the change,
not just randomly change it.
Okay. I 'll take some time to do the analysis. I think we also should
keep in mind of possible remote readahead that would cause unnecessary
penalty.
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>