From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yann Droneaud Subject: Re: [PATCH 1/2] infiniband: Help gcc generate better code for ocrdma_srq_toggle_bit Date: Sat, 31 Jan 2015 12:07:46 +0100 Message-ID: <1422702466.3030.4.camel@opteya.com> References: <1421419196-4659-1-git-send-email-linux@rasmusvillemoes.dk> <87twz7ho25.fsf@rasmusvillemoes.dk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <87twz7ho25.fsf-qQsb+v5E8BnlAoU/VqSP6n9LOBIZ5rWg@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Rasmus Villemoes Cc: Roland Dreier , Sean Hefty , Hal Rosenstock , linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Devesh Sharma , Selvin Xavier , Mitesh Ahuja List-Id: linux-rdma@vger.kernel.org Hi, Le samedi 31 janvier 2015 =C3=A0 00:00 +0100, Rasmus Villemoes a =C3=A9= crit : > ping >=20 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= =2E > On Fri, Jan 16 2015, Rasmus Villemoes wrot= e: >=20 > > 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/o= crdma/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, s= o > > saving a few useless instructions might be worthwhile. > > > > Signed-off-by: Rasmus Villemoes > > --- > > 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 ocr= dma_srq *srq, int idx) > > int i =3D idx / 32; > > unsigned int mask =3D (1 << (idx % 32)); > > =20 > > - if (srq->idx_bit_fields[i] & mask) > > - srq->idx_bit_fields[i] &=3D ~mask; > > - else > > - srq->idx_bit_fields[i] |=3D mask; > > + srq->idx_bit_fields[i] ^=3D mask; > > } > > =20 > > static int ocrdma_hwq_free_cnt(struct ocrdma_qp_hwq_info *q) > -- Regards. --=20 Yann Droneaud OPTEYA -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html