Re: SSD and IO schedulers

[Theodore Tso <tytso@mit.edu>]

On Thu, Apr 09, 2009 at 07:56:32PM -0400, Bill Davidsen wrote:
> This is good information, and if I ever configure a netbook for run 
> fsync-tester I shall avoid the DL scheduler. ;-(
>
> However... this test, and several others designed to find the ultimate  
> performance limits of disk io, don't mimic any typical use of most 
> desktops and virtually all netbooks.
>
> Is there a benchmark which would return so useful data for typical use, 
> doing some mail, some browsing, and maybe some light presentation, 
> spreadsheet, or word processing. None of those uses are likely to 
> generate this level of io, this file size, etc. The number of users is 
> one, it's not used as a server, and probably most of the tuning done (if 
> any) is aimed at battery life rather than blinding speed with a three 
> digit load average.

As long as you don't believe a netbook user will ever try to type an
e-mail using a mail reader like alpine (which is what Linus uses),
while running "yum update" in the background, sure.  But if you don't
think that is a normal use case, I'll let you argue with Linus on that
score.  In any case, the big-file-write-and-flush plus fsync-tester
was designed to roughly replicate this scenario which Linus saw on his
desktop system.

    	     			  	   	       - Ted