[dpdk-dev] [PATCH v2 5/5] examples/kni: improve zeroing statistics

Dan Gora dg at adax.com
Wed Sep 26 16:48:29 CEST 2018


On Wed, Sep 26, 2018 at 11:01 AM, Ferruh Yigit <ferruh.yigit at intel.com> wrote:
> On 9/19/2018 8:55 PM, Dan Gora wrote:
>> The worker threads incrementing the rx/tx_packets race with the signal
>> handler from the main thread zeroing the entire statistics structure.
>> This can cause the statistics to fail to be zeroed, even when there
>> is no traffic on those interfaces.
>>
>> Improve zeroing the statistics by only incrementing rx/tx_packets
>> in worker threads by a non-zero amount.  This limits the race to the
>> periods in which traffic is actually being received or transmitted.
>
> Not sure about introducing an extra check to datapath for possible error on
> stats zero. I am for dropping this patch, what do you think?

This is literally adding one instruction to the datapath.  Not even an
atomic instruction.  There is no effect on the performance caused by
this change.

Is that not better than the user (like me who experienced this)
wondering why they cannot zero the counters even when there is no
traffic?

-d


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