> -----Original Message----- > From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Qiu, Michael > Sent: Wednesday, September 23, 2015 7:57 AM > To: Stephen Hemminger; De Lara Guarch, Pablo > Cc: dev at dpdk.org > Subject: Re: [dpdk-dev] [PATCH v2] ethdev: add new RX/TX queue state arrays > in rte_eth_dev_data > > On 2015/9/22 6:40, Stephen Hemminger wrote: > > On Wed, 16 Sep 2015 22:51:24 +0100 > > Pablo de Lara <pablo.de.lara.guarch at intel.com> wrote: > > > >> This is important to avoid trying to start/stop twice a queue, > >> which will result in undefined behaviour > >> (which may cause RX/TX disruption). > >> > >> Mind that only the PMDs which have queue_start/stop functions > >> have been changed to update this field, as the functions will > >> check the queue state before switching it. > >> > >> Signed-off-by: Pablo de Lara <pablo.de.lara.guarch at intel.com> > > I agree that the DPDK API should check for buggy manipulation > > in the control path. But this should be done in generic code. > > Anything where you have to change any driver is making more work > > than necessary. > > I agree with you, but I have a question, why we need expose the queue > start and stop function to app? > > In my opinion, user app will hardly to start a device but stop the > device queue. what's the purpose of it? >
There are use cases when application need to start/stop individual queues. DPDK vhost app would be one of the examples. Konstantin > Thanks, > Michael
