Re: an optimization for dm-bufio and dm-integrity

[Mike Snitzer <snitzer@redhat.com>]

On Wed, Jul 19 2017 at 12:22pm -0400,
Milan Broz <mbroz@redhat.com> wrote:

> On 07/19/2017 05:39 PM, Mike Snitzer wrote:
> > On Wed, Jul 19 2017 at 11:30P -0400,
> > Mikulas Patocka <mpatocka@redhat.com> wrote:
> > 
> >> Hi Mike
> >>
> >> Some times ago, I sent this patch as dm-bufio optimization (it doesn't 
> >> have to write full buffers, it only writes a part of the buffer that 
> >> changed). You delayed the patch until the next kernel.
> >>
> >> Will you submit the patch to the current kernel?
> > 
> > Sorry about that.  It obviously fell off my radar.
> > 
> > I'll review it and see if I can make the justification for it going into
> > 4.13-rc2.  But unfortunately the 4.13 merge window closed this past
> > Sunday when Linus released v4.13-rc1
> > 
> > I'll let you know though, thanks.
> 
> Just FYI: I am just running some tests with the stack space fix and
> this patch and the performance improvement for 4k sectors is really big
> (compared to 4.12).

If you could quantify the performance improvement that would be helpful.

Are you also using the plugging patch?