GNU bug report logs - #6996
`byte-compile-report-ops', `byte-code-meter', `byte-metering-on', what are they?

Previous Next

To add a comment to this bug, you must first unarchive it, by sending
a message to control AT debbugs.gnu.org, with unarchive 6996 in the body.
You can then email your comments to 6996 AT debbugs.gnu.org in the normal way.

Toggle the display of automated, internal messages from the tracker.

Message #5 received at submit <at> debbugs.gnu.org (full text, mbox):

From: MON KEY <monkey <at> sandpframing.com>
To: bug-gnu-emacs <at> gnu.org
Subject: `byte-compile-report-ops', `byte-code-meter', `byte-metering-on',
	what are they?
Date: Tue, 7 Sep 2010 17:33:22 -0400

`byte-compile-report-ops', `byte-code-meter', `byte-metering-on', what are they?

Following files:
 src/bytecode.c
 lisp/emacs-lisp/bytecomp.el

define the variables `byte-code-meter', `byte-metering-on' and a function
`byte-compile-report-ops'.

there is this comment in bytecomp.el
 ";;; report metering (see the hacks in bytecode.c)"

I can't find reference to these anywher in docs, archives, etc.
What do these things do?

(byte-compile-report-ops)
=> Debugger entered--Lisp error: (void-variable byte-code-meter)

--
/s_P\

Message #10 received at 6996-done <at> debbugs.gnu.org (full text, mbox):

From: Glenn Morris <rgm <at> gnu.org>
Cc: 6996-done <at> debbugs.gnu.org
Subject: Re: bug#6996: `byte-compile-report-ops', `byte-code-meter',
	`byte-metering-on', what are they?
Date: Tue, 7 Sep 2010 19:29:06 -0400

MON KEY wrote (on Tue, 7 Sep 2010 at 17:33 -0400):

> `byte-compile-report-ops', `byte-code-meter', `byte-metering-on', what are they?
> 
> Following files:
>  src/bytecode.c
>  lisp/emacs-lisp/bytecomp.el
> 
> define the variables `byte-code-meter', `byte-metering-on' and a function
> `byte-compile-report-ops'.

From src/bytecode.c:

#ifdef BYTE_CODE_METER
  DEFVAR_LISP ("byte-code-meter", &Vbyte_code_meter,...
...
#endif

In the comments in the same file:

  define BYTE_CODE_METER to enable generation of a byte-op usage
  histogram.

So if you are interested, why not define it, re-build and see what
happens?

I have no idea what it does, but since it is not on by default since
1991, and is not documented anywhere, I don't see it as a bug if it
doesn't do whatever it is supposed to do. At the worst it is dead code
that could be deleted.

Message #13 received at 6996 <at> debbugs.gnu.org (full text, mbox):

From: MON KEY <monkey <at> sandpframing.com>
To: 6996 <at> debbugs.gnu.org
Subject: Re: bug#6996: Acknowledgement (`byte-compile-report-ops',
	`byte-code-meter', `byte-metering-on', what are they?)
Date: Wed, 8 Sep 2010 03:30:23 -0400

> I have no idea what it does,

If you don't I doubt few others do either, maybe Jim Blandy?

> but since it is not on by default since 1991,

That's nearly 20 years ago!

> and is not documented anywhere, I don't see it as a bug if it
> doesn't do whatever it is supposed to do.

Its a bug b/c bytecomp.el exposes/provides it.

> At the worst it is dead code that could be deleted.

At the very least there must be _some_ reason the code has
persisted... Hence, my tepid curiosity.

--
/s_P\

Message #16 received at 6996 <at> debbugs.gnu.org (full text, mbox):

From: Stefan Monnier <monnier <at> iro.umontreal.ca>
To: MON KEY <monkey <at> sandpframing.com>
Cc: 6996 <at> debbugs.gnu.org
Subject: Re: bug#6996: Acknowledgement (`byte-compile-report-ops',
	`byte-code-meter', `byte-metering-on', what are they?)
Date: Wed, 08 Sep 2010 11:15:09 +0200

>> At the worst it is dead code that could be deleted.
> At the very least there must be _some_ reason the code has
> persisted... Hence, my tepid curiosity.

From the description it was code that tried to figure out which
byte-codes were used more often.  Probably this was used at some point
to help decide which byte-code to add/keep as well as how much to
optimize paticular byte-codes.


        Stefan

Previous Next

GNU bug tracking system
Copyright (C) 1999 Darren O. Benham, 1997,2003 nCipher Corporation Ltd, 1994-97 Ian Jackson.