Messages in this thread | | | From | Yann Droneaud <> | Date | Sat, 31 Jan 2015 12:07:46 +0100 | Subject | Re: [PATCH 1/2] infiniband: Help gcc generate better code for ocrdma_srq_toggle_bit |
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Hi,
Le samedi 31 janvier 2015 à 00:00 +0100, Rasmus Villemoes a écrit : > ping >
As you're fixing ocrdma driver, I think you might want to find people @emulex.com to review your patches.
BTW, there's no MAINTAINERS entry for ocrdma driver ... which is a pity.
> On Fri, Jan 16 2015, Rasmus Villemoes <linux@rasmusvillemoes.dk> wrote: > > > gcc emits a surprising amount of code in order to flip a bit. One > > would think that a single instruction is enough. > > > > $ scripts/bloat-o-meter /tmp/ocrdma_verbs.o drivers/infiniband/hw/ocrdma/ocrdma_verbs.o > > add/remove: 0/0 grow/shrink: 0/3 up/down: 0/-142 (-142) > > function old new delta > > ocrdma_post_srq_recv 498 460 -38 > > ocrdma_poll_cq 2010 1962 -48 > > ocrdma_discard_cqes 495 439 -56 > > > > All three calls of ocrdma_srq_toggle_bit happen within spinlocks, so > > saving a few useless instructions might be worthwhile. > > > > Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> > > --- > > drivers/infiniband/hw/ocrdma/ocrdma_verbs.c | 5 +---- > > 1 file changed, 1 insertion(+), 4 deletions(-) > > > > diff --git a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c > > index fb8d8c4dfbb9..eff11e6c6183 100644 > > --- a/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c > > +++ b/drivers/infiniband/hw/ocrdma/ocrdma_verbs.c > > @@ -1484,10 +1484,7 @@ static void ocrdma_srq_toggle_bit(struct ocrdma_srq *srq, int idx) > > int i = idx / 32; > > unsigned int mask = (1 << (idx % 32)); > > > > - if (srq->idx_bit_fields[i] & mask) > > - srq->idx_bit_fields[i] &= ~mask; > > - else > > - srq->idx_bit_fields[i] |= mask; > > + srq->idx_bit_fields[i] ^= mask; > > } > > > > static int ocrdma_hwq_free_cnt(struct ocrdma_qp_hwq_info *q) > --
Regards.
-- Yann Droneaud OPTEYA
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