Hi Maxime,
> -----Original Message-----
> From: Maxime Coquelin <maxime.coque...@redhat.com>
> Sent: Thursday, November 3, 2022 7:10 AM
> To: Vargas, Hernan <hernan.var...@intel.com>; dev@dpdk.org;
> gak...@marvell.com; t...@redhat.com
> Cc: Chautru, Nicolas <nicolas.chau...@intel.com>; Zhang, Qi Z
> <qi.z.zh...@intel.com>
> Subject: Re: [PATCH v7 1/1] baseband/acc100: add detection for deRM corner
> cases
>
>
>
> On 11/1/22 05:13, Hernan Vargas wrote:
> > Add function to detect if de-ratematch pre-processing is recommended
> > for SW corner cases.
> > Some specific 5GUL FEC corner cases may cause unintended back pressure
> > and in some cases a potential stability issue on the ACC100.
> > The PMD can detect such code block configuration and issue an info
> > message to the user.
> >
> > Signed-off-by: Hernan Vargas <hernan.var...@intel.com>
> > ---
> > drivers/baseband/acc/acc_common.h | 8 ++++
> > drivers/baseband/acc/rte_acc100_pmd.c | 55
> +++++++++++++++++++++++++--
> > 2 files changed, 60 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/baseband/acc/acc_common.h
> > b/drivers/baseband/acc/acc_common.h
> > index eae7eab4e9..6213b0b61e 100644
> > --- a/drivers/baseband/acc/acc_common.h
> > +++ b/drivers/baseband/acc/acc_common.h
> > @@ -123,6 +123,14 @@
> > #define ACC_HARQ_ALIGN_64B 64
> > #define ACC_MAX_ZC 384
> >
> > +/* De-ratematch code rate limitation for recommended operation */
> > +#define ACC_LIM_03 2 /* 0.03 */ #define ACC_LIM_09 6 /* 0.09 */
> > +#define ACC_LIM_14 9 /* 0.14 */ #define ACC_LIM_21 14 /* 0.21 */
> > +#define ACC_LIM_31 20 /* 0.31 */ #define ACC_MAX_E (128 * 1024 - 2)
> > +
> > /* Helper macro for logging */
> > #define rte_acc_log(level, fmt, ...) \
> > rte_log(RTE_LOG_ ## level, RTE_LOG_NOTICE, fmt "\n", \ diff --git
> > a/drivers/baseband/acc/rte_acc100_pmd.c
> > b/drivers/baseband/acc/rte_acc100_pmd.c
> > index 23bc5d25bb..47609f95b7 100644
> > --- a/drivers/baseband/acc/rte_acc100_pmd.c
> > +++ b/drivers/baseband/acc/rte_acc100_pmd.c
> > @@ -756,6 +756,14 @@ acc100_queue_setup(struct rte_bbdev *dev,
> uint16_t queue_id,
> > ret = -ENOMEM;
> > goto free_lb_out;
> > }
> > + q->derm_buffer = rte_zmalloc_socket(dev->device->driver->name,
> > + RTE_BBDEV_TURBO_MAX_CB_SIZE * 10,
> > + RTE_CACHE_LINE_SIZE, conf->socket);
> > + if (q->derm_buffer == NULL) {
> > + rte_bbdev_log(ERR, "Failed to allocate derm_buffer memory");
> > + ret = -ENOMEM;
> > + goto free_companion_ring_addr;
> > + }
> >
> > /*
> > * Software queue ring wraps synchronously with the HW when it
> > reaches @@ -776,7 +784,7 @@ acc100_queue_setup(struct rte_bbdev *dev,
> uint16_t queue_id,
> > q_idx = acc100_find_free_queue_idx(dev, conf);
> > if (q_idx == -1) {
> > ret = -EINVAL;
> > - goto free_companion_ring_addr;
> > + goto free_derm_buffer;
> > }
> >
> > q->qgrp_id = (q_idx >> ACC100_GRP_ID_SHIFT) & 0xF; @@ -804,6
> +812,9
> > @@ acc100_queue_setup(struct rte_bbdev *dev, uint16_t queue_id,
> > dev->data->queues[queue_id].queue_private = q;
> > return 0;
> >
> > +free_derm_buffer:
> > + rte_free(q->derm_buffer);
> > + q->derm_buffer = NULL;
> > free_companion_ring_addr:
> > rte_free(q->companion_ring_addr);
> > q->companion_ring_addr = NULL;
> > @@ -890,6 +901,7 @@ acc100_queue_release(struct rte_bbdev *dev,
> uint16_t q_id)
> > /* Mark the Queue as un-assigned */
> > d->q_assigned_bit_map[q->qgrp_id] &= (0xFFFFFFFFFFFFFFFF -
> > (uint64_t) (1 << q->aq_id));
> > + rte_free(q->derm_buffer);
> > rte_free(q->companion_ring_addr);
> > rte_free(q->lb_in);
> > rte_free(q->lb_out);
> > @@ -3111,10 +3123,41 @@ harq_loopback(struct acc_queue *q, struct
> rte_bbdev_dec_op *op,
> > return 1;
> > }
> >
> > +/* Assess whether a work around is recommended for the deRM corner
> > +cases */ static inline bool derm_workaround_recommended(struct
> > +rte_bbdev_op_ldpc_dec *ldpc_dec, struct acc_queue *q) {
> > + if (!is_acc100(q))
> > + return false;
> > + int32_t e = ldpc_dec->cb_params.e;
> > + int q_m = ldpc_dec->q_m;
> > + int z_c = ldpc_dec->z_c;
> > + int K = (ldpc_dec->basegraph == 1 ? ACC_K_ZC_1 : ACC_K_ZC_2) * z_c;
> > + bool recommended = false;
> > +
> > + if (ldpc_dec->basegraph == 1) {
> > + if ((q_m == 4) && (z_c >= 320) && (e * ACC_LIM_31 > K * 64))
> > + recommended = true;
> > + else if ((e * ACC_LIM_21 > K * 64))
> > + recommended = true;
> > + } else {
> > + if (q_m <= 2) {
> > + if ((z_c >= 208) && (e * ACC_LIM_09 > K * 64))
> > + recommended = true;
> > + else if ((z_c < 208) && (e * ACC_LIM_03 > K * 64))
> > + recommended = true;
> > + } else if (e * ACC_LIM_14 > K * 64)
> > + recommended = true;
> > + }
> > +
> > + return recommended;
> > +}
> > +
> > /** Enqueue one decode operations for ACC100 device in CB mode */
> > static inline int
> > enqueue_ldpc_dec_one_op_cb(struct acc_queue *q, struct
> rte_bbdev_dec_op *op,
> > - uint16_t total_enqueued_cbs, bool same_op)
> > + uint16_t total_enqueued_cbs, bool same_op,
> > + struct rte_bbdev_queue_data *q_data)
> > {
> > int ret;
> > if (unlikely(check_bit(op->ldpc_dec.op_flags,
> > @@ -3168,6 +3211,12 @@ enqueue_ldpc_dec_one_op_cb(struct acc_queue
> *q, struct rte_bbdev_dec_op *op,
> > } else {
> > struct acc_fcw_ld *fcw;
> > uint32_t seg_total_left;
> > +
> > + if (derm_workaround_recommended(&op->ldpc_dec, q)) {
> > + RTE_SET_USED(q_data);
> Why do we need q_data if it is not being used?
As you can guess this notably allows customer do consider running deRM from
here as a local patch hence keeping the q_data accessible.
Basically we keep the prototype of the function enqueue_ldpc_dec_one_op_cb()
compatible with such usage.
I believe this is a good practice here. Let us know if you are not convinced.
Thanks
Nic
>
> > + rte_bbdev_log(INFO, "Corner case may require deRM
> pre-processing");
> > + }
> > +
> > fcw = &desc->req.fcw_ld;
> > q->d->fcw_ld_fill(op, fcw, harq_layout);
> >
> > @@ -3721,7 +3770,7 @@ acc100_enqueue_ldpc_dec_cb(struct
> rte_bbdev_queue_data *q_data,
> > ops[i]->ldpc_dec.n_cb, ops[i]->ldpc_dec.q_m,
> > ops[i]->ldpc_dec.n_filler, ops[i]-
> >ldpc_dec.cb_params.e,
> > same_op);
> > - ret = enqueue_ldpc_dec_one_op_cb(q, ops[i], i, same_op);
> > + ret = enqueue_ldpc_dec_one_op_cb(q, ops[i], i, same_op,
> q_data);
> > if (ret < 0) {
> > acc_enqueue_invalid(q_data);
> > break;
