From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dennis Dalessandro Subject: [PATCH 4/7] IB/hfi1: Get rid of divide in pio buffer allocator Date: Tue, 25 Oct 2016 13:12:28 -0700 Message-ID: <20161025201228.15765.53426.stgit@scvm10.sc.intel.com> References: <20161025194241.15765.8903.stgit@scvm10.sc.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20161025194241.15765.8903.stgit-9QXIwq+3FY+1XWohqUldA0EOCMrvLtNR@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: dledford-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org Cc: linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Mike Marciniszyn , Sebastian Sanchez List-Id: linux-rdma@vger.kernel.org From: Sebastian Sanchez The div instruction shows costly in profiles. Reviewed-by: Mike Marciniszyn Signed-off-by: Sebastian Sanchez Signed-off-by: Dennis Dalessandro --- drivers/infiniband/hw/hfi1/pio.c | 11 +++++++---- drivers/infiniband/hw/hfi1/pio.h | 1 + 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/drivers/infiniband/hw/hfi1/pio.c b/drivers/infiniband/hw/hfi1/pio.c index e60fe3e..00a0e9e 100644 --- a/drivers/infiniband/hw/hfi1/pio.c +++ b/drivers/infiniband/hw/hfi1/pio.c @@ -1242,6 +1242,7 @@ int sc_enable(struct send_context *sc) sc->free = 0; sc->alloc_free = 0; sc->fill = 0; + sc->fill_wrap = 0; sc->sr_head = 0; sc->sr_tail = 0; sc->flags = 0; @@ -1385,7 +1386,7 @@ struct pio_buf *sc_buffer_alloc(struct send_context *sc, u32 dw_len, unsigned long flags; unsigned long avail; unsigned long blocks = dwords_to_blocks(dw_len); - unsigned long start_fill; + u32 fill_wrap; int trycount = 0; u32 head, next; @@ -1428,8 +1429,11 @@ retry: head = sc->sr_head; /* "allocate" the buffer */ - start_fill = sc->fill; sc->fill += blocks; + fill_wrap = sc->fill_wrap; + sc->fill_wrap += blocks; + if (sc->fill_wrap >= sc->credits) + sc->fill_wrap = sc->fill_wrap - sc->credits; /* * Fill the parts that the releaser looks at before moving the head. @@ -1458,8 +1462,7 @@ retry: spin_unlock_irqrestore(&sc->alloc_lock, flags); /* finish filling in the buffer outside the lock */ - pbuf->start = sc->base_addr + ((start_fill % sc->credits) - * PIO_BLOCK_SIZE); + pbuf->start = sc->base_addr + fill_wrap * PIO_BLOCK_SIZE; pbuf->size = sc->credits * PIO_BLOCK_SIZE; pbuf->end = sc->base_addr + pbuf->size; pbuf->block_count = blocks; diff --git a/drivers/infiniband/hw/hfi1/pio.h b/drivers/infiniband/hw/hfi1/pio.h index bd19507..498b548 100644 --- a/drivers/infiniband/hw/hfi1/pio.h +++ b/drivers/infiniband/hw/hfi1/pio.h @@ -119,6 +119,7 @@ struct send_context { unsigned long fill; /* official alloc count */ unsigned long alloc_free; /* copy of free (less cache thrash) */ u32 __percpu *buffers_allocated;/* count of buffers allocated */ + u32 fill_wrap; /* tracks fill within ring */ /* releaser fields */ spinlock_t release_lock ____cacheline_aligned_in_smp; u32 sr_tail; /* shadow ring tail */ -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html