In ARCH(s) that spinlock() serves also as SFENCE prevent
an another explicit SFENCE. (e.g. X86).
To prevent an extra 'if' to know whether lock is really taken and it's
not a single threaded application encapsulates the mlx5_single_threaded
flag as part of bf->need_lock.
Signed-off-by: Yishai Hadas <yishaih@xxxxxxxxxxxx>
---
providers/mlx5/mlx5.c | 2 +-
providers/mlx5/qp.c | 7 ++++---
2 files changed, 5 insertions(+), 4 deletions(-)
diff --git a/providers/mlx5/mlx5.c b/providers/mlx5/mlx5.c
index 87c85df..eeaf5ac 100644
--- a/providers/mlx5/mlx5.c
+++ b/providers/mlx5/mlx5.c
@@ -524,7 +524,7 @@ static int get_num_low_lat_uuars(int tot_uuars)
*/
static int need_uuar_lock(struct mlx5_context *ctx, int uuarn)
{
- if (uuarn == 0)
+ if (uuarn == 0 || mlx5_single_threaded)
return 0;
if (uuarn >= (ctx->tot_uuars - ctx->low_lat_uuars) * 2)
diff --git a/providers/mlx5/qp.c b/providers/mlx5/qp.c
index de68b1c..1d5a2f9 100644
--- a/providers/mlx5/qp.c
+++ b/providers/mlx5/qp.c
@@ -930,11 +930,11 @@ out:
/* Make sure that the doorbell write happens before the memcpy
* to WC memory below */
- mmio_wc_start();
-
ctx = to_mctx(ibqp->context);
if (bf->need_lock)
- mlx5_spin_lock(&bf->lock);
+ mmio_wc_spinlock(&bf->lock.lock);
+ else
+ mmio_wc_start();
if (!ctx->shut_up_bf && nreq == 1 && bf->uuarn &&
(inl || ctx->prefer_bf) && size > 1 &&
@@ -953,6 +953,7 @@ out:
* writes doorbell 2, and it's write is flushed earlier. Since
* the mmio_flush_writes is CPU local, this will result in the HCA seeing
* doorbell 2, followed by doorbell 1.
+ * Flush before toggling bf_offset to be latency oriented.
*/
mmio_flush_writes();
bf->offset ^= bf->buf_size;
--
1.8.3.1
--
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