diff options
| author |   Xavier Simonart <xavier.simonart@intel.com> | 2019-03-08 13:32:53 +0100 |
|---|---|---|
| committer | Xavier Simonart <xavier.simonart@intel.com> | 2019-03-08 13:32:53 +0100 |
| commit | 3d17d9c7e0daae0b82973283a23f3e85d0decabd (patch) | |
| tree | f857a5bd7783e1942b70802658173a38d18d9059 /VNFs/DPPD-PROX/handle_lat.c | |
| parent | d813669721c37f0dcbb8f12b950cde7362265c50 (diff) | |
Fix PROX generator latency
When PROX fails to transmit packets (e.g. because switch or NIC
is overloaded) some cleanup needs to be done related to packet id
and latency.
In addition, in some casesi, the clock estimate is slighly over-estimated
which might result, in rare cases, in negative (hence very high) latencies,
due to the extrapolation of timestamps.
This has been workarounded bydecreasing the extrapolation, tolerating up to 1%
clock estimate error
Change-Id: I1ba17dfe0d5e2f9f9167f4f087ed0d96da1293c2
Signed-off-by: Xavier Simonart <xavier.simonart@intel.com>
Diffstat (limited to 'VNFs/DPPD-PROX/handle_lat.c')
| -rw-r--r-- | VNFs/DPPD-PROX/handle_lat.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/VNFs/DPPD-PROX/handle_lat.c b/VNFs/DPPD-PROX/handle_lat.c index 93652d47..b4e016ec 100644 --- a/VNFs/DPPD-PROX/handle_lat.c +++ b/VNFs/DPPD-PROX/handle_lat.c @@ -437,7 +437,7 @@ static uint32_t task_lat_early_loss_detect(struct task_lat *task, uint32_t packe static uint64_t tsc_extrapolate_backward(struct task_lat *task, uint64_t tsc_from, uint64_t bytes, uint64_t tsc_minimum) { -#ifdef NO_EXTRAPOLATION +#ifdef NO_LAT_EXTRAPOLATION uint64_t tsc = tsc_from; #else uint64_t tsc = tsc_from - task->bytes_to_tsc[bytes]; @@ -806,11 +806,14 @@ static void init_task_lat(struct task_base *tbase, struct task_args *targ) PROX_PANIC(task->bytes_to_tsc == NULL, "Failed to allocate %u bytes (in huge pages) for bytes_to_tsc\n", max_frame_size); + // There are cases where hz estimate might be slighly over-estimated + // This results in too much extrapolation + // Only account for 99% of extrapolation to handle cases with up to 1% error clocks for (unsigned int i = 0; i < max_frame_size * MAX_PKT_BURST ; i++) { if (bytes_per_hz == UINT64_MAX) task->bytes_to_tsc[i] = 0; else - task->bytes_to_tsc[i] = (rte_get_tsc_hz() * i) / bytes_per_hz; + task->bytes_to_tsc[i] = (rte_get_tsc_hz() * i * 0.99) / bytes_per_hz; } } |