Re: Kernel SCM: When does CVS fall down where it REALLY matters?

[Larry McVoy]

On Mon, Mar 11, 2002 at 09:12:31AM -0800, Randy.Dunlap wrote:
> On Mon, 11 Mar 2002, Larry McVoy wrote:
> 
> | On Thu, Mar 07, 2002 at 08:59:47PM -0300, Rik van Riel wrote:
> | > 3) graphical 2-way merging tool like bitkeeper has
> | >    (this might not seem essential to people who have
> | >    never used it, but it has saved me many many hours)
> |
> | I haven't verified this, but I suspect what Rik is using is the 3-way
> | file merge.  If it looks like
> |
> | 	http://www.bitkeeper.com/newmerge.gif
> |
> | that's a 3 way file merge, the 2 big side by side windows are showing
> | you 3 diffs, the diff from the ancestor to the local version in the left
> | window, the diff from the ancestor to the remote version in the right
> | window, and then side by side diffs in that they are lined up.
> |
> | If Rik is using the 2 way file merge and likes that, he's in for a quantum
> | leap in productivity, commercial customers have reported as much as an
> | 18:1 productivity increase from the 3 way file merge.
> 
> Just curious, how is this productivity increase measured?

They redid the same really nasty merge with the old tools, with Sun's
file merge, and the new filemerge.  It was a bit more than 18x faster
with the new file merge.

This same customer site, which hacks the kernel by the way, claims that 
well over 90% of their BK usage is spent merging, so the productivity 
gains in merging are translated almost 1:1 into wall clock gains.