[PATCH RFC] ARM: unwind: optimize to not convert each table value but the address
catalin.marinas at arm.com
Wed Nov 30 12:58:48 EST 2011
On Sun, Nov 20, 2011 at 11:12:42PM +0000, Uwe Kleine-König wrote:
> The offsets in the unwind index section are signed 31 bit numbers and
> the structs are sorted by this offset. So it first has offsets between
> 0x40000000 and 0x7fffffff (i.e. the negative offsets) and then offsets
> between 0x00000000 and 0x3fffffff. When seperating these two blocks the
> numbers are sorted even when interpreting the offsets as unsigned longs.
> So instead of converting each offset hit during bisection to an absolute
> address, first determine which of the blocks needs to be searched and
> then adapt the key to find for the offset while bisecting using a simple
> unsigned long comparison.
> In my tests this is faster than the original implementation modifying
> the unwind index section by 4.5%.
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Nicolas Pitre <nico at fluxnic.net>
> Signed-off-by: Uwe Kleine-König <u.kleine-koenig at pengutronix.de>
The patch looks fine. Could you please post the final combined patch
(and also pipe it through checkpatch.pl as it seems to have some too
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