[v2,5/5] event/octeontx2: update start timestamp periodically
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Commit Message
From: Pavan Nikhilesh <pbhagavatula@marvell.com>
Update start timestamp periodically to prevent drift.
Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
---
drivers/event/octeontx2/otx2_tim_evdev.c | 28 +++++++++++++++++++++++
drivers/event/octeontx2/otx2_tim_evdev.h | 7 ++++--
drivers/event/octeontx2/otx2_tim_worker.c | 19 +++++++++++++++
3 files changed, 52 insertions(+), 2 deletions(-)
@@ -389,6 +389,31 @@ otx2_tim_ring_create(struct rte_event_timer_adapter *adptr)
return rc;
}
+static void
+otx2_tim_calibrate_start_tsc(struct otx2_tim_ring *tim_ring)
+{
+#define OTX2_TIM_CALIB_ITER 1E6
+ uint32_t real_bkt, bucket;
+ int icount, ecount = 0;
+ uint64_t bkt_cyc;
+
+ for (icount = 0; icount < OTX2_TIM_CALIB_ITER; icount++) {
+ real_bkt = otx2_read64(tim_ring->base + TIM_LF_RING_REL) >> 44;
+ bkt_cyc = rte_rdtsc();
+ bucket = (bkt_cyc - tim_ring->ring_start_cyc) /
+ tim_ring->tck_int;
+ bucket = bucket % (tim_ring->nb_bkts);
+ tim_ring->ring_start_cyc = bkt_cyc - (real_bkt *
+ tim_ring->tck_int);
+ if (bucket != real_bkt)
+ ecount++;
+ }
+ tim_ring->last_updt_cyc = bkt_cyc;
+ otx2_tim_dbg("Bucket mispredict %3.2f distance %d\n",
+ 100 - (((double)(icount - ecount) / (double)icount) * 100),
+ bucket - real_bkt);
+}
+
static int
otx2_tim_ring_start(const struct rte_event_timer_adapter *adptr)
{
@@ -423,8 +448,11 @@ otx2_tim_ring_start(const struct rte_event_timer_adapter *adptr)
tim_ring->ring_start_cyc = rsp->timestarted;
#endif
tim_ring->tck_int = NSEC2TICK(tim_ring->tck_nsec, rte_get_timer_hz());
+ tim_ring->tot_int = tim_ring->tck_int * tim_ring->nb_bkts;
tim_ring->fast_div = rte_reciprocal_value_u64(tim_ring->tck_int);
+ otx2_tim_calibrate_start_tsc(tim_ring);
+
fail:
return rc;
}
@@ -25,6 +25,7 @@
#define TIM_LF_RAS_INT_W1S (0x308)
#define TIM_LF_RAS_INT_ENA_W1S (0x310)
#define TIM_LF_RAS_INT_ENA_W1C (0x318)
+#define TIM_LF_RING_REL (0x400)
#define TIM_BUCKET_W1_S_CHUNK_REMAINDER (48)
#define TIM_BUCKET_W1_M_CHUNK_REMAINDER ((1ULL << (64 - \
@@ -139,13 +140,15 @@ struct otx2_tim_evdev {
struct otx2_tim_ring {
uintptr_t base;
- struct rte_reciprocal_u64 fast_div;
uint16_t nb_chunk_slots;
uint32_t nb_bkts;
+ uint64_t last_updt_cyc;
uint64_t ring_start_cyc;
+ uint64_t tck_int;
+ uint64_t tot_int;
struct otx2_tim_bkt *bkt;
struct rte_mempool *chunk_pool;
- uint64_t tck_int;
+ struct rte_reciprocal_u64 fast_div;
rte_atomic64_t arm_cnt;
uint8_t prod_type_sp;
uint8_t enable_stats;
@@ -38,6 +38,23 @@ tim_format_event(const struct rte_event_timer * const tim,
entry->wqe = tim->ev.u64;
}
+static inline void
+tim_sync_start_cyc(struct otx2_tim_ring *tim_ring)
+{
+ uint64_t cur_cyc = rte_rdtsc();
+ uint32_t real_bkt;
+
+ if (cur_cyc - tim_ring->last_updt_cyc > tim_ring->tot_int) {
+ real_bkt = otx2_read64(tim_ring->base + TIM_LF_RING_REL) >> 44;
+ cur_cyc = rte_rdtsc();
+
+ tim_ring->ring_start_cyc = cur_cyc -
+ (real_bkt * tim_ring->tck_int);
+ tim_ring->last_updt_cyc = cur_cyc;
+ }
+
+}
+
static __rte_always_inline uint16_t
tim_timer_arm_burst(const struct rte_event_timer_adapter *adptr,
struct rte_event_timer **tim,
@@ -49,6 +66,7 @@ tim_timer_arm_burst(const struct rte_event_timer_adapter *adptr,
uint16_t index;
int ret;
+ tim_sync_start_cyc(tim_ring);
for (index = 0; index < nb_timers; index++) {
if (tim_arm_checks(tim_ring, tim[index]))
break;
@@ -99,6 +117,7 @@ tim_timer_arm_tmo_brst(const struct rte_event_timer_adapter *adptr,
return 0;
}
+ tim_sync_start_cyc(tim_ring);
while (arr_idx < nb_timers) {
for (idx = 0; idx < OTX2_TIM_MAX_BURST && (arr_idx < nb_timers);
idx++, arr_idx++) {