On Thu, Sep 20, 2018 at 01:08:32PM -0400, Devesh Sharma wrote:
> Remove the lock around the doorbell. It isn't necessary
> and was a bottleneck for multithreaded clients. Performance of
> spdk improves by 40% with it removed.
>
> Signed-off-by: JD Zheng <jiandong.zheng@xxxxxxxxxxxx>
> Signed-off-by: Jonathan Richardson <jonathan.richardson@xxxxxxxxxxxx>
> Signed-off-by: Devesh Sharma <devesh.sharma@xxxxxxxxxxxx>
> ---
> providers/bnxt_re/db.c | 2 --
> providers/bnxt_re/main.c | 1 -
> providers/bnxt_re/main.h | 1 -
> providers/bnxt_re/verbs.c | 2 --
> 4 files changed, 6 deletions(-)
>
> diff --git a/providers/bnxt_re/db.c b/providers/bnxt_re/db.c
> index a79f871..2896ceb 100644
> --- a/providers/bnxt_re/db.c
> +++ b/providers/bnxt_re/db.c
> @@ -44,11 +44,9 @@ static void bnxt_re_ring_db(struct bnxt_re_dpi *dpi,
> {
> __le64 *dbval;
>
> - pthread_spin_lock(&dpi->db_lock);
> dbval = (__le64 *)&hdr->indx;
> udma_to_device_barrier();
> iowrite64(dpi->dbpage, dbval);
> - pthread_spin_unlock(&dpi->db_lock);
> }
Nope, you have to convert this provider to use the mmio accessor
helpers if you want to do this.
Ie get rid of iowrite64/iowrite32 and use the macros in util/mmio.h
They provide the necessary guarentee for atomicity to allow the lock
to be removed.
Jason
