On 10/22/2020 8:46 PM, Long Li wrote:
From: Stephen Hemminger <step...@networkplumber.org>
The values for Rx and Tx copy break should be tunable rather
than hard coded constants.
The rx_copybreak sets the threshold where the driver uses an
external mbuf to avoid having to copy data. Setting 0 for copybreak
will cause driver to always create an external mbuf. Setting
a value greater than the MTU would prevent it from ever making
an external mbuf and always copy. The default value is 256 (bytes).
Likewise the tx_copybreak sets the threshold where the driver
aggregates multiple small packets into one request. If tx_copybreak
is 0 then each packet goes as a VMBus request (no copying).
If tx_copybreak is set larger than the MTU, then all packets smaller
than the chunk size of the VMBus send buffer will be copied; larger
packets always have to go as a single direct request. The default
value is 512 (bytes).
Signed-off-by: Stephen Hemminger <step...@networkplumber.org>
Signed-off-by: Long Li <lon...@microsoft.com>
<...>
@@ -45,6 +45,10 @@
DEV_RX_OFFLOAD_VLAN_STRIP | \
DEV_RX_OFFLOAD_RSS_HASH)
+#define NETVSC_ARG_LATENCY "latency"
+#define NETVSC_ARG_RXBREAK "rx_copybreak"
+#define NETVSC_ARG_TXBREAK "tx_copybreak"
+
Can you please document new devargs in the driver documentation?
<...>
@@ -181,12 +167,32 @@ static int hn_parse_args(const struct rte_eth_dev *dev)
return -EINVAL;
}
- ret = rte_kvargs_process(kvlist, "latency", hn_set_latency, hv);
- if (ret)
- PMD_DRV_LOG(ERR, "Unable to process latency arg\n");
+ for (i = 0; i != kvlist->count; ++i) {
+ const struct rte_kvargs_pair *pair = &kvlist->pairs[i];
+
+ if (!strcmp(pair->key, NETVSC_ARG_LATENCY))
+ latency = atoi(pair->value);
+ else if (!strcmp(pair->key, NETVSC_ARG_RXBREAK))
+ rx_break = atoi(pair->value);
+ else if (!strcmp(pair->key, NETVSC_ARG_TXBREAK))
+ tx_break = atoi(pair->value);
+ }
+
Instead of accessing to the kvlist internals, I think better to use
'rte_kvargs_process()' as done previously.
If the reason to remove callback is to not create a callback for each argument,
a generic one can be used for all.
+ if (latency >= 0) {
+ PMD_DRV_LOG(DEBUG, "set latency %d usec", latency);
+ hv->latency = latency * 1000; /* usec to nsec */
+ }
+ if (rx_break >= 0) {
+ PMD_DRV_LOG(DEBUG, "rx copy break set to %d", rx_break);
+ hv->rx_copybreak = rx_break;
+ }
+ if (tx_break >= 0) {
+ PMD_DRV_LOG(DEBUG, "tx copy break set to %d", tx_break);
+ hv->tx_copybreak = tx_break;
+ }
When 'rte_kvargs_process()' used, the valued can be assigned directly to
'hv->tx_copybreak', if the argument is not available, it won't be updated, so
above check can be dropped.
