[v2] net/af_packet: improve Tx statistics accuracy
Checks
Commit Message
When sendto call fails and ENOBUFS error is being set some of the
packets are actually successfully transmitted. There is no available
count of those packets, so in order to make the statistics more
accurate, all the previously enqueued packets will be considered
successful, even though this is not entirely correct.
Before:
testpmd Tx statistics:
TX-packets: 7529062 TX-errors: 3702150 TX-bytes: 451743720
pktgen Rx statistics:
Total Rx Pkts: 10700700
After:
testpmd TX statistics:
TX-packets: 11510625 TX-errors: 0 TX-bytes: 690637500
pktgen Rx statistics:
Total Rx Pkts: 10974307
Fixes: 74b7fc0a0ff1 ("net/af_packet: fix packet bytes counting")
Cc: ciwillia@brocade.com
Cc: stable@dpdk.org
Signed-off-by: Flavia Musatescu <flavia.musatescu@intel.com>
---
v2:
* Changed the comment
---
drivers/net/af_packet/rte_eth_af_packet.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
Comments
On Thu, 10 Oct 2019 18:34:30 +0100
Flavia Musatescu <flavia.musatescu@intel.com> wrote:
> When sendto call fails and ENOBUFS error is being set some of the
> packets are actually successfully transmitted. There is no available
> count of those packets, so in order to make the statistics more
> accurate, all the previously enqueued packets will be considered
> successful, even though this is not entirely correct.
>
> Before:
> testpmd Tx statistics:
> TX-packets: 7529062 TX-errors: 3702150 TX-bytes: 451743720
> pktgen Rx statistics:
> Total Rx Pkts: 10700700
>
> After:
> testpmd TX statistics:
> TX-packets: 11510625 TX-errors: 0 TX-bytes: 690637500
> pktgen Rx statistics:
> Total Rx Pkts: 10974307
>
> Fixes: 74b7fc0a0ff1 ("net/af_packet: fix packet bytes counting")
> Cc: ciwillia@brocade.com
> Cc: stable@dpdk.org
>
> Signed-off-by: Flavia Musatescu <flavia.musatescu@intel.com>
>
> ---
> v2:
> * Changed the comment
> ---
> drivers/net/af_packet/rte_eth_af_packet.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/af_packet/rte_eth_af_packet.c b/drivers/net/af_packet/rte_eth_af_packet.c
> index 6df09f2..df281bf 100644
> --- a/drivers/net/af_packet/rte_eth_af_packet.c
> +++ b/drivers/net/af_packet/rte_eth_af_packet.c
> @@ -244,8 +244,12 @@ eth_af_packet_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
> }
>
> /* kick-off transmits */
> - if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1) {
> - /* error sending -- no packets transmitted */
> + if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1 &&
> + errno != ENOBUFS) {
> + /*
> + * In case of a ENOBUFS error all of the enqueued packets will
> + * be considered successful even though only some are sent.
> + */
> num_tx = 0;
> num_tx_bytes = 0;
> }
What about EINTR or EAGAIN?
On 10/10/2019 19:35, Stephen Hemminger wrote:
> On Thu, 10 Oct 2019 18:34:30 +0100
> Flavia Musatescu <flavia.musatescu@intel.com> wrote:
>
>> When sendto call fails and ENOBUFS error is being set some of the
>> packets are actually successfully transmitted. There is no available
>> count of those packets, so in order to make the statistics more
>> accurate, all the previously enqueued packets will be considered
>> successful, even though this is not entirely correct.
>>
>> Before:
>> testpmd Tx statistics:
>> TX-packets: 7529062 TX-errors: 3702150 TX-bytes: 451743720
>> pktgen Rx statistics:
>> Total Rx Pkts: 10700700
>>
>> After:
>> testpmd TX statistics:
>> TX-packets: 11510625 TX-errors: 0 TX-bytes: 690637500
>> pktgen Rx statistics:
>> Total Rx Pkts: 10974307
>>
>> Fixes: 74b7fc0a0ff1 ("net/af_packet: fix packet bytes counting")
>> Cc: ciwillia@brocade.com
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: Flavia Musatescu <flavia.musatescu@intel.com>
>>
>> ---
>> v2:
>> * Changed the comment
>> ---
>> drivers/net/af_packet/rte_eth_af_packet.c | 8 ++++++--
>> 1 file changed, 6 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/af_packet/rte_eth_af_packet.c b/drivers/net/af_packet/rte_eth_af_packet.c
>> index 6df09f2..df281bf 100644
>> --- a/drivers/net/af_packet/rte_eth_af_packet.c
>> +++ b/drivers/net/af_packet/rte_eth_af_packet.c
>> @@ -244,8 +244,12 @@ eth_af_packet_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
>> }
>>
>> /* kick-off transmits */
>> - if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1) {
>> - /* error sending -- no packets transmitted */
>> + if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1 &&
>> + errno != ENOBUFS) {
>> + /*
>> + * In case of a ENOBUFS error all of the enqueued packets will
>> + * be considered successful even though only some are sent.
>> + */
>> num_tx = 0;
>> num_tx_bytes = 0;
>> }
> What about EINTR or EAGAIN?
Hi Stephen,
I agree with EAGAIN error case as I was able to test this scenario and
check the statistics.
Can we get an EINTR error in case of a nonblocking operation
(MSG_DONTWAIT flag is being used)? Is this a common situation and will
the gain justify the cost of an additional check? Do you have any
suggestions for how I could test this scenario?
Thanks,
Flavia
@@ -244,8 +244,12 @@ eth_af_packet_tx(void *queue, struct rte_mbuf **bufs, uint16_t nb_pkts)
}
/* kick-off transmits */
- if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1) {
- /* error sending -- no packets transmitted */
+ if (sendto(pkt_q->sockfd, NULL, 0, MSG_DONTWAIT, NULL, 0) == -1 &&
+ errno != ENOBUFS) {
+ /*
+ * In case of a ENOBUFS error all of the enqueued packets will
+ * be considered successful even though only some are sent.
+ */
num_tx = 0;
num_tx_bytes = 0;
}