Re: [PATCH] Fix Kconfig performance bug
From: David Gibson (david_at_gibson.dropbear.id.au)
Date: 10/31/05
- Previous message: Andrew Morton: "Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19"
- In reply to: David Gibson: "Re: [PATCH] Fix Kconfig performance bug"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Date: Mon, 31 Oct 2005 17:55:21 +1100 To: Roman Zippel <zippel@linux-m68k.org>, kbuild-devel@lists.sourceforge.net, linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org
On Fri, Oct 21, 2005 at 11:49:55AM +1000, David Gibson wrote:
> On Fri, Oct 21, 2005 at 02:46:30AM +0200, Roman Zippel wrote:
> > Hi,
> >
> > On Thu, 20 Oct 2005, David Gibson wrote:
> >
> > > When doing its recursive dependency check, scripts/kconfig/conf uses
> > > the flag SYMBOL_CHECK_DONE to avoid rechecking a symbol it has already
> > > checked. However, that flag is only set at the top level, so if a
> > > symbol is first encountered as a dependency of another symbol it will
> > > be rechecked every time it is encountered until it's encountered at
> > > the top level.
> >
> > You're correct, the check does too much.
> >
> > > Index: working-2.6/scripts/kconfig/symbol.c
> > > ===================================================================
> > > --- working-2.6.orig/scripts/kconfig/symbol.c 2005-10-20 12:40:45.000000000 +1000
> > > +++ working-2.6/scripts/kconfig/symbol.c 2005-10-20 12:41:43.000000000 +1000
> > > @@ -758,6 +758,8 @@
> > > out:
> > > if (sym2)
> > > printf(" %s", sym->name);
> > > + else
> > > + sym->flags |= SYMBOL_CHECK_DONE;
> > > sym->flags &= ~SYMBOL_CHECK;
> > > return sym2;
> > > }
> >
> > Actually this way it becomes redundant with SYMBOL_CHECKED, could you
> > merge these two flags? The above check would be also probably better:
>
> Ok, done. There is now only SYMBOL_CHECKED (seemed a clearer name to
> me), but it's semantics are like those of SYMBOL_CHECK_DONE were.
>
> > if (sym2) {
> > printf(" %s", sym->name);
> > if (sym2 == sym) {
> > printf("\n");
> > sym2 = NULL;
> > }
> > }
> >
> > So that this check will stop when it hits the start symbol and continue
> > looking for more dependency problems, which is I think I intended with the
> > original code.
>
> Erm.. ok. I don't entirely understand the intent of this is, but
> applied anyway.
>
> > > Index: working-2.6/scripts/kconfig/zconf.y
> > > ===================================================================
> > > --- working-2.6.orig/scripts/kconfig/zconf.y 2005-10-20 12:40:45.000000000 +1000
> > > +++ working-2.6/scripts/kconfig/zconf.y 2005-10-20 12:41:43.000000000 +1000
> > > @@ -495,10 +495,9 @@
> > > exit(1);
> > > menu_finalize(&rootmenu);
> > > for_all_symbols(i, sym) {
> > > +/* fprintf(stderr, "Checking %s...\n", sym->name); */
> >
> > One "quilt refresh" missing? :-)
>
> Oops. Something like that.
>
> Oh.. one caveat, the diffs I have here to zconf.tab.c_shipped are
> direct edits to match zconf.y - I didn't regenerate the file with
> bison. I've done that to getting a whole lot of irrelevant changes in
> the patch because I'm using a different version of bison to that used
> for the existing zconf.tab.[ch]_shipped
>
> Anyway, revised version below:
Now that 2.6.14 is out, do you intend to pass this patch on to Linus?
-- David Gibson | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_ | _way_ _around_! http://www.ozlabs.org/people/dgibson - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
- Previous message: Andrew Morton: "Re: [Lhms-devel] [PATCH 0/7] Fragmentation Avoidance V19"
- In reply to: David Gibson: "Re: [PATCH] Fix Kconfig performance bug"
- Messages sorted by: [ date ] [ thread ] [ subject ] [ author ]
Relevant Pages
|
|
