From: Andrew Rybchenko <arybchenko@solarflare.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>,
A.McLoughlin <aideen.mcloughlin@intel.com>,
Wenzhuo Lu <wenzhuo.lu@intel.com>,
Jingjing Wu <jingjing.wu@intel.com>,
Bernard Iremonger <bernard.iremonger@intel.com>
Cc: <dev@dpdk.org>, <david.marchand@redhat.com>, <stable@dpdk.org>,
"Thomas Monjalon" <thomas@monjalon.net>,
Stephen Hemminger <stephen@networkplumber.org>
Subject: Re: [dpdk-stable] [dpdk-dev] [PATCH] app/testpmd: fix doubling of 'total TX dropped'
Date: Tue, 16 Jul 2019 15:23:02 +0300 [thread overview]
Message-ID: <6dec383f-a559-7036-8ecd-22f11f2c1d5f@solarflare.com> (raw)
In-Reply-To: <c1cdafc1-580b-713a-555d-ed31a031d5a5@intel.com>
On 7/15/19 5:53 PM, Ferruh Yigit wrote:
> On 7/12/2019 9:32 AM, A.McLoughlin wrote:
>> The 'Accumulated forward statistics for all ports' incorrectly displayed
>> double the actual value for 'total_tx_dropped'. This was because 2
>> lines in the same function both incremented total_tx_dropped every time
>> a packet was dropped. I removed one of these lines to fix this issue.
>>
>> Fixes: 53324971a14e ("app/testpmd: display/clear forwarding stats on demand")
>> Cc: david.marchand@redhat.com
>> Cc: stable@dpdk.org
>>
>> Signed-off-by: A.McLoughlin <aideen.mcloughlin@intel.com>
>> ---
>> app/test-pmd/testpmd.c | 1 -
>> 1 file changed, 1 deletion(-)
>>
>> diff --git a/app/test-pmd/testpmd.c b/app/test-pmd/testpmd.c
>> index 3ed3523b7..c41bada50 100644
>> --- a/app/test-pmd/testpmd.c
>> +++ b/app/test-pmd/testpmd.c
>> @@ -1555,7 +1555,6 @@ fwd_stats_display(void)
>> total_recv += stats.ipackets;
>> total_xmit += stats.opackets;
>> total_rx_dropped += stats.imissed;
>> - total_tx_dropped += ports_stats[pt_id].tx_dropped;
>> total_tx_dropped += stats.oerrors;
>> total_rx_nombuf += stats.rx_nombuf;
>>
>>
>
> Hi Aideen,
>
> Indeed 'rte_eth_stats->oerrors' and 'tx_dropped' are different values,
>
> in testpmd, 'TX-total' is taken as "total_xmit + total_tx_dropped", from this
> description it may be fair to say
> "total_tx_dropped = oerrors + tx_dropped"
>
> This is easier to see in HW devices, 'oerrors' is the packets sent to HW but HW
> reported failure for some reason, so these packets not transmitted to the medium.
> 'tx_dropped' is mostly calculated by application, driver returns packets that
> can't able to sent to HW, so application can re-try to send or free them and
> increase 'tx_dropped' counter.
>
>
> The problem is in the virtual drivers, the packets not able to sent are
> calculated as 'oerrors' and tx_burst functions returns the number of the
> successfully sent packets which cause application calculate remaining ones as
> 'tx_dropped' which cause the duplication.
I don't understand how it is. Tx burst returns a number of owned packets
(either successfully transmitted or internally dropped/freed). If it is
smaller than number of packets in request, other packets are either
retried or calculated as tx_dropped.
> In virtual drivers we need to give a decision, if free the wrong packets and
> increase the 'oerrors' or return packets backs to application without increasing
> the 'oerrors', so that application can try to do something with packets or free
> them increasing 'tx_dropped'.
>
> @David, @Andrew, do you have a suggestion?
next prev parent reply other threads:[~2019-07-16 12:23 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-12 8:32 [dpdk-stable] " A.McLoughlin
2019-07-12 13:33 ` Iremonger, Bernard
2019-07-15 14:53 ` [dpdk-stable] [dpdk-dev] " Ferruh Yigit
2019-07-16 12:23 ` Andrew Rybchenko [this message]
2019-07-16 14:23 ` Ferruh Yigit
2019-07-16 14:28 ` Bruce Richardson
2019-07-16 15:00 ` Andrew Rybchenko
2019-07-16 15:29 ` Ferruh Yigit
2019-07-23 11:16 ` David Marchand
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