Re: [PATCH v2 4/8] scripts: add glimpse.sh for indexing the kernel

["Luis R. Rodriguez" <mcgrof@kernel.org>]

On Fri, Jun 17, 2016 at 11:44:26AM +0200, Julia Lawall wrote:
> I'm not sure that this is worth it.  It adds a dependency on a tool that
> seems not to be well maintained.  In terms of Coccinelle, I'm not sure
> that it gives a big benefit.
> 
> Attached is a graph showing the file selection time for Coccinelle for a
> selection of fairly complex semantic patches.  Coccigrep is just a
> line-by-line regexp search implemented in ocaml, gitgrep uses git grep.
> In most cases, glimpse is clearly faster.
> 
> On the other hand, it seems that glimpse often selects more files.
> Sometimes a few more, eg 16 vs 14, and sometimes quite a lot more, eg 538
> vs 236.  I suspect that this is because glimpse considers _ to be a space,
> and thus it can have many false positives.  There are, however, a few
> cases where glimpse also selects fewer files.
> 
> The file processing time (ie parsing the file, searching for, matches of
> the semantic patch in the file, and performing the transformation) is
> normally much higher than the file selection time.
> 
> So it seems that git grep is currently a better option for the kernel.

Great, thanks, consider this patch dropped, do we want the heuristics
for the cache index in place though or should I drop that as well ?

  Luis