Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 373e098e authored May 24, 2018 by Christophe Leroy Committed by Michael Ellerman Jun 04, 2018

powerpc/32: Optimise __csum_partial()



Improve __csum_partial by interleaving loads and adds.

On a 8xx, it brings neither improvement nor degradation.
On a 83xx, it brings a 25% improvement.

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>

parent 1128bb78

arch/powerpc/lib/checksum_32.S

+11 −2

Original line number	Diff line number	Diff line
		@@ -47,16 +47,25 @@ _GLOBAL(__csum_partial)
		bdnz 2b
		21: srwi. r6,r4,4 /* # blocks of 4 words to do */
		beq 3f
		lwz r0,4(r3)
		mtctr r6
		22: lwz r0,4(r3)
		lwz r6,8(r3)
		adde r5,r5,r0
		lwz r7,12(r3)
		adde r5,r5,r6
		lwzu r8,16(r3)
		adde r5,r5,r7
		bdz 23f
		22: lwz r0,4(r3)
		adde r5,r5,r8
		lwz r6,8(r3)
		adde r5,r5,r0
		lwz r7,12(r3)
		adde r5,r5,r6
		lwzu r8,16(r3)
		adde r5,r5,r7
		adde r5,r5,r8
		bdnz 22b
		23: adde r5,r5,r8
		3: andi. r0,r4,2
		beq+ 4f
		lhz r0,4(r3)