xcscope.el slow - linux kernel

xcscope.el slow - linux kernel

[Rafal Kurcz]

Hello

When I use cscope outside of emacs with latest linux kernel it works
very quickly.
It finds "global definition:__free_pages_ok " and "functions calling a
function:__free_pages_ok " in less than 0.1 sec.

The above operations take about 2 sec when using xcscope.el.

1. Can I force xcscope.el to perform those operations in less than 0.1
sec ?
2. Where can I find the "fast" version of xcscope.el / cscope-
indexer ?
3. How should I generate cscope data files ?
  a. with cscope-indexer ?
  b. with "make cscope" directly from linux kernel ?
  c. with "cscope -b -k -q" ?

I work on Pentium 4 2.4 Ghz.

Thank You for help

Re: xcscope.el slow - linux kernel

[Thorsten Bonow]

>>>>> "Rafal" == Rafal Kurcz <pawlaczus@yahoo.com> writes:

    Rafal> Hello When I use cscope outside of emacs with latest linux kernel it
    Rafal> works very quickly.  It finds "global definition:__free_pages_ok "
    Rafal> and "functions calling a function:__free_pages_ok " in less than 0.1
    Rafal> sec.

    Rafal> The above operations take about 2 sec when using xcscope.el.

Yup, takes even longer on my old Athlon 700.

    Rafal> 1. Can I force xcscope.el to perform those operations in less than
    Rafal>    0.1 sec ?

I guess you mean "much faster than 2.0 seconds" in order to match the 0.1 seconds
from the bare bones cscope interface. xcscope.el is just an interface to cscope,
it can't be faster.

    Rafal> 2. Where can I find the "fast" version of xcscope.el / cscope-
    Rafal> indexer ?

Sigh, on your computer, after you wrote it ;-) I'm not happy with cscope-indexer
and I think that the script can be replaced with lisp code, but I do not have
the time to do so. So don't hold your breath... and it's lisp, calling external
programs: don't expect it to become much faster.

There are several versions of cscope interfaces for emacsen out there, maybe you
find one which is faster. I doubt it.

    Rafal> 3. How should I generate cscope data files ?
    Rafal> a. with cscope-indexer ?

This just calls "cscope -b"

    Rafal> b. with "make cscope" directly from linux kernel ?

This just calls "cscope -b -k -q". Unfortunatedly, on my system this leads to a
warning message about "Mismatch of option -q" when you call cscope next time via
xscope.

    Rafal> c. with "cscope -b -k -q" ?

See above.

    Rafal> I work on Pentium 4 2.4 Ghz.

You could hack cscope-indexer to include the "-q" or even the "-k" option (You
can customise xcscope to use a different script). But it would be nicer to be
able to specify these as options to the script from within xcscope. But than you
have to write a wrapper script for cscope, too. To prevent that darned option
mismatch, xcscope must do the cscope calls with the same options, but
unfortunately, customising the value of "cscope-program" to "cscope -q" doesn't
work, because xcscope than looks for a program called "cscope -q" and can't find
it.

    Rafal> Thank You for help

Sorry, no help, just explaining that scratching your itch is difficult.

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Re: xcscope.el slow - linux kernel

[Rafal Kurcz]

Thank You for an answer
> I guess you mean "much faster than 2.0 seconds" in order to match the 0.1 seconds
> from the bare bones cscope interface. xcscope.el is just an interface to cscope,
> it can't be faster.

In fact I don't expect it to be faster but it looks like the interface
is at least 20 times slower than the bare cscope.
I think it is too much. Furthermore searching architecture-dependent
symbols (e.g. symbols from arch/alpha/mm/init.c) takes about 8 secs on
my Pentium 4 2.4 GHz (80 times slower than the bare cscope).
Cscope shows the list of candidates to jump in less than 0.1 secs. Why
not just take this list into emacs and display it ?
It seems not to be so time consuming task.

> You could hack cscope-indexer to include the "-q" or even the "-k" option
I've already done all those tricks with "-q", "-b" and "-k" options.
Unfortunately it didn't help.

Thank You for any help.