net/mlx5: convert timestamp to completion index

The application provides timestamps in Tx mbuf as clocks,
the hardware performs scheduling on Clock Queue completion index
match. This patch introduces the timestamp-to-completion-index
inline routine.

Signed-off-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
Acked-by: Matan Azrad <matan@mellanox.com>

diff --git a/drivers/net/mlx5/mlx5.h b/drivers/net/mlx5/mlx5.h
index bb2c096..3304f0d 100644 (file)
--- a/drivers/net/mlx5/mlx5.h
+++ b/drivers/net/mlx5/mlx5.h
@@ -585,6 +585,8 @@ struct mlx5_dev_txpp {
        rte_atomic32_t err_miss_int; /* Missed service interrupt. */
        rte_atomic32_t err_rearm_queue; /* Rearm Queue errors. */
        rte_atomic32_t err_clock_queue; /* Clock Queue errors. */
+       rte_atomic32_t err_ts_past; /* Timestamp in the past. */
+       rte_atomic32_t err_ts_future; /* Timestamp in the distant future. */
 };
 
 /*

diff --git a/drivers/net/mlx5/mlx5_rxtx.h b/drivers/net/mlx5/mlx5_rxtx.h
index 974a847..d082cd7 100644 (file)
--- a/drivers/net/mlx5/mlx5_rxtx.h
+++ b/drivers/net/mlx5/mlx5_rxtx.h
@@ -719,4 +719,59 @@ mlx5_txpp_convert_rx_ts(struct mlx5_dev_ctx_shared *sh, uint64_t ts)
        return (ts & UINT32_MAX) + (ts >> 32) * NS_PER_S;
 }
 
+/**
+ * Convert timestamp from mbuf format to linear counter
+ * of Clock Queue completions (24 bits)
+ *
+ * @param sh
+ *   Pointer to the device shared context to fetch Tx
+ *   packet pacing timestamp and parameters.
+ * @param ts
+ *   Timestamp from mbuf to convert.
+ * @return
+ *   positive or zero value - completion ID to wait
+ *   negative value - conversion error
+ */
+static __rte_always_inline int32_t
+mlx5_txpp_convert_tx_ts(struct mlx5_dev_ctx_shared *sh, uint64_t mts)
+{
+       uint64_t ts, ci;
+       uint32_t tick;
+
+       do {
+               /*
+                * Read atomically two uint64_t fields and compare lsb bits.
+                * It there is no match - the timestamp was updated in
+                * the service thread, data should be re-read.
+                */
+               rte_compiler_barrier();
+               ci = rte_atomic64_read(&sh->txpp.ts.ci_ts);
+               ts = rte_atomic64_read(&sh->txpp.ts.ts);
+               rte_compiler_barrier();
+               if (!((ts ^ ci) << (64 - MLX5_CQ_INDEX_WIDTH)))
+                       break;
+       } while (true);
+       /* Perform the skew correction, positive value to send earlier. */
+       mts -= sh->txpp.skew;
+       mts -= ts;
+       if (unlikely(mts >= UINT64_MAX / 2)) {
+               /* We have negative integer, mts is in the past. */
+               rte_atomic32_inc(&sh->txpp.err_ts_past);
+               return -1;
+       }
+       tick = sh->txpp.tick;
+       MLX5_ASSERT(tick);
+       /* Convert delta to completions, round up. */
+       mts = (mts + tick - 1) / tick;
+       if (unlikely(mts >= (1 << MLX5_CQ_INDEX_WIDTH) / 2 - 1)) {
+               /* We have mts is too distant future. */
+               rte_atomic32_inc(&sh->txpp.err_ts_future);
+               return -1;
+       }
+       mts <<= 64 - MLX5_CQ_INDEX_WIDTH;
+       ci += mts;
+       ci >>= 64 - MLX5_CQ_INDEX_WIDTH;
+       return ci;
+}
+
 #endif /* RTE_PMD_MLX5_RXTX_H_ */

diff --git a/drivers/net/mlx5/mlx5_txpp.c b/drivers/net/mlx5/mlx5_txpp.c
index 8f7284b..95b9127 100644 (file)
--- a/drivers/net/mlx5/mlx5_txpp.c
+++ b/drivers/net/mlx5/mlx5_txpp.c
@@ -860,6 +860,11 @@ mlx5_txpp_start_service(struct mlx5_dev_ctx_shared *sh)
        int flags;
        int ret;
 
+       rte_atomic32_set(&sh->txpp.err_miss_int, 0);
+       rte_atomic32_set(&sh->txpp.err_rearm_queue, 0);
+       rte_atomic32_set(&sh->txpp.err_clock_queue, 0);
+       rte_atomic32_set(&sh->txpp.err_ts_past, 0);
+       rte_atomic32_set(&sh->txpp.err_ts_future, 0);
        /* Attach interrupt handler to process Rearm Queue completions. */
        flags = fcntl(sh->txpp.echan->fd, F_GETFL);
        ret = fcntl(sh->txpp.echan->fd, F_SETFL, flags | O_NONBLOCK);