> On Thu, 2008-08-14 at 19:44 -0400, Theodore Tso wrote:
> > > I spent a bunch of time hammering on different ways to fix this without
> > > increasing nr_requests, and it was a mixture of needing better tuning in
> > > btrfs and needing to init mapping->writeback_index on inode allocation.
> > >
> > > So, today's numbers for creating 30 kernel trees in sequence:
> > >
> > > Btrfs defaults 57.41 MB/s
> > > Btrfs dup no csum 74.59 MB/s
> > > Btrfs no duplication 76.83 MB/s
> > > Btrfs no dup no csum no inline 76.85 MB/s
> >
> > What sort of script are you using? Basically something like this?
> >
> > for i in `seq 1 30` do
> > mkdir $i; cd $i
> > tar xjf /usr/src/linux-2.6.28.tar.bz2
> > cd ..
> > done
>
> Similar. I used compilebench -i 30 -r 0, which means create 30 initial
> kernel trees and then do nothing. compilebench simulates compiles by
> writing to the FS files of the same size that you would get by creating
> kernel trees or compiling them.
>
> The idea is to get all of the IO without needing to keep 2.6.28.tar.bz2
> in cache or the compiler using up CPU.
>
>
http://www.oracle.com/~mason/compilebench
