Previously, the PMD used a common monitor callback to determine
CQE ownership for power-aware polling. However, when a CQE contained
an invalid opcode(MLX5_CQE_INVALID), ownership bit was not reliable.
As a result, the monitor condition could falsely indicate CQE
availability and cause the CPU to wake up unnecessarily during
low traffic periods.
This resulted in spurious wakeups in monitor-wait mode and reduced
the expected power savings, as cores exited the sleep state even
when no valid CQEs were available.
This patch introduces a dedicated callback that skips invalid CQEs
and optimizes power efficiency by preventing false wakeups caused
by hardware-owned or invalid entries.
Fixes: a8f0df6bf98d ("net/mlx5: support power monitoring")
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Sivaprasad Tummala <[email protected]>
---
drivers/net/mlx5/mlx5_rx.c | 17 ++++++++++++++++-
1 file changed, 16 insertions(+), 1 deletion(-)
diff --git a/drivers/net/mlx5/mlx5_rx.c b/drivers/net/mlx5/mlx5_rx.c
index 420a03068d..2765b4b730 100644
--- a/drivers/net/mlx5/mlx5_rx.c
+++ b/drivers/net/mlx5/mlx5_rx.c
@@ -295,6 +295,20 @@ mlx5_monitor_callback(const uint64_t value,
return (value & m) == v ? -1 : 0;
}
+static int
+mlx5_monitor_cqe_own_callback(const uint64_t value,
+ const uint64_t opaque[RTE_POWER_MONITOR_OPAQUE_SZ])
+{
+ const uint64_t m = opaque[CLB_MSK_IDX];
+ const uint64_t v = opaque[CLB_VAL_IDX];
+ const uint64_t match = ((value & m) == v);
+ const uint64_t opcode = MLX5_CQE_OPCODE(value);
+ const uint64_t valid_op = (opcode ^ MLX5_CQE_INVALID);
+
+ /* ownership bit is not valid for invalid opcode; CQE is HW owned */
+ return -(match & valid_op);
+}
+
int mlx5_get_monitor_addr(void *rx_queue, struct rte_power_monitor_cond *pmc)
{
struct mlx5_rxq_data *rxq = rx_queue;
@@ -312,12 +326,13 @@ int mlx5_get_monitor_addr(void *rx_queue, struct
rte_power_monitor_cond *pmc)
pmc->addr = &cqe->validity_iteration_count;
pmc->opaque[CLB_VAL_IDX] = vic;
pmc->opaque[CLB_MSK_IDX] = MLX5_CQE_VIC_INIT;
+ pmc->fn = mlx5_monitor_callback;
} else {
pmc->addr = &cqe->op_own;
pmc->opaque[CLB_VAL_IDX] = !!idx;
pmc->opaque[CLB_MSK_IDX] = MLX5_CQE_OWNER_MASK;
+ pmc->fn = mlx5_monitor_cqe_own_callback;
}
- pmc->fn = mlx5_monitor_callback;
pmc->size = sizeof(uint8_t);
return 0;
}
--
2.43.0
