Re: [PATCH v2 10/37] baseband/acc100: avoid mux for small inbound frames

[Maxime Coquelin]

On 8/20/22 04:31, Hernan Vargas wrote:

Update check_mux to avoid multiplexing small inbound frames.
Preventing to multiplex code blocks when K < 512B per specs.

It looks like a fix, and so should Fixes tag be added an stable cc'ed.

Signed-off-by: Hernan Vargas <hernan.var...@intel.com>
---
  drivers/baseband/acc100/acc100_pmd.h     |  1 +
  drivers/baseband/acc100/rte_acc100_pmd.c | 16 +++++++++++-----
  2 files changed, 12 insertions(+), 5 deletions(-)

diff --git a/drivers/baseband/acc100/acc100_pmd.h 
b/drivers/baseband/acc100/acc100_pmd.h
index 0c9810ca56..19a1f434bc 100644
--- a/drivers/baseband/acc100/acc100_pmd.h
+++ b/drivers/baseband/acc100/acc100_pmd.h
@@ -135,6 +135,7 @@
  #define ACC100_DEC_OFFSET     (80)
  #define ACC100_EXT_MEM /* Default option with memory external to CPU */
  #define ACC100_HARQ_OFFSET_THRESHOLD 1024
+#define ACC100_LIMIT_DL_MUX_BITS 534

/* Constants from K0 computation from 3GPP 38.212 Table 5.4.2.1-2 */

  #define ACC100_N_ZC_1 66 /* N = 66 Zc for BG 1 */
diff --git a/drivers/baseband/acc100/rte_acc100_pmd.c 
b/drivers/baseband/acc100/rte_acc100_pmd.c
index 5d09908fd0..71409e11a1 100644
--- a/drivers/baseband/acc100/rte_acc100_pmd.c
+++ b/drivers/baseband/acc100/rte_acc100_pmd.c
@@ -3548,20 +3548,25 @@ acc100_enqueue_enc_cb(struct rte_bbdev_queue_data 
*q_data,
  }

/* Check we can mux encode operations with common FCW */

-static inline bool
+static inline int16_t
  check_mux(struct rte_bbdev_enc_op **ops, uint16_t num) {
        uint16_t i;
        if (num <= 1)
-               return false;
+               return 1;
        for (i = 1; i < num; ++i) {
                /* Only mux compatible code blocks */
                if (memcmp((uint8_t *)(&ops[i]->ldpc_enc) + ACC100_ENC_OFFSET,
                                (uint8_t *)(&ops[0]->ldpc_enc) +
                                ACC100_ENC_OFFSET,
                                ACC100_CMP_ENC_SIZE) != 0)
-                       return false;
+                       return i;
        }
-       return true;
+       /* Avoid multiplexing small inbound size frames */
+       int Kp = (ops[0]->ldpc_enc.basegraph == 1 ? 22 : 10) *
+                       ops[0]->ldpc_enc.z_c - ops[0]->ldpc_enc.n_filler;
+       if (Kp  <= ACC100_LIMIT_DL_MUX_BITS)
+               return 1;
+       return num;
  }

/** Enqueue encode operations for ACC100 device in CB mode. */

@@ -3583,7 +3588,8 @@ acc100_enqueue_ldpc_enc_cb(struct rte_bbdev_queue_data 
*q_data,
                }
                avail--;
                enq = RTE_MIN(left, ACC100_MUX_5GDL_DESC);
-               if (check_mux(&ops[i], enq)) {
+               enq = check_mux(&ops[i], enq);
+               if (enq > 1) {
                        ret = enqueue_ldpc_enc_n_op_cb(q, &ops[i],
                                        desc_idx, enq);
                        if (ret < 0) {