Re: [Ext2-devel] disk throughput

Andreas Dilger <[e-mail]> writes:
> On Nov 05, 2001  00:04 -0800, Andrew Morton wrote:
[..]
> > With the ialloc.c change, plus the other changes I mentioned
> > the time to create all these directories and files and then run
> > /bin/sync fell from 1:53 to 0:28.  Fourfold.
> 
> In the end, though, while the old heuristic has a good theory, it _may_
> be that in practise, you are _always_ seeking to get data from different
> groups, rather than _theoretically_ seeking because of fragmented files.
> I don't know what the answer is - probably depends on finding "valid"
> benchmarks (cough).

Another heuristic to try make be to only use a different blockgroup
for when the mkdir()s are seperate in time. i.e. rather than
doing 
	if ( 0 && .. 
use something like
	if ((last_time + 100) < jiffes && ... 
		last_time = jiffies;
which would in theory use the old behaviour for sparodic mkdirs
and the new behaviour for things like 'untar' et al.

M.