Date: Thu, 28 Apr 2016 12:15:04 -0700 From: bazzoola <bazzoola@gmail.com> To: Luigi Rizzo <rizzo@iet.unipi.it> Cc: Navdeep Parhar <np@freebsd.org>, "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: Re: netmap overrun counters Message-ID: <c004919a-21fd-51d9-eb35-8458ebe97652@gmail.com> In-Reply-To: <CA%2BhQ2%2Bj%2BQyOTfKHhkp3KRQsD7aTdA=o4rQAZ_hnYXB8_x9py6Q@mail.gmail.com> References: <cd306a81-3a4b-6386-a059-73d455d3c931@gmail.com> <9fd88731-2cdf-a6da-4b4e-f97bb120696a@FreeBSD.org> <863506de-870e-0da4-81d3-6ab537feaa2b@gmail.com> <CA%2BhQ2%2Bj%2BQyOTfKHhkp3KRQsD7aTdA=o4rQAZ_hnYXB8_x9py6Q@mail.gmail.com>
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On 04/28/2016 12:06 PM, Luigi Rizzo wrote: > > > On Thursday, April 28, 2016, bazzoola <bazzoola@gmail.com > <mailto:bazzoola@gmail.com>> wrote: > > > > On 04/28/2016 11:35 AM, Navdeep Parhar wrote: > > On 04/28/2016 11:13, bazzoola wrote: > >> Hi! > >> > >> Two questions: > >> > >> (1) Is there a way to know when netmap rx rings overrun? Most NIC > >> drivers provide MPC (missed packet count) and sysctl for rx_overrun. > >> > >> I would like to know if my application is not reading as fast, > i.e., no > >> frames are being dropped. > > > > A NIC's hardware counters don't distinguish between netmap or normal > > operation so you can monitor the existing sysctls for rx > drops/overruns. > > > > Regards, > > Navdeep > > > > Navdeep, > > I am not asking about NIC's ring overrun. As you know netmap has its own > rings. Is there a way to know if netmap's rx ring overrun? > > > Overruns by definition can only be counted by the NIC > > Cheers > Luigi > > Luigi, I will rephrase the question to avoid the 'overrun' definition. (1) if my application is not reading fast enough is there a way to know if netmap's rx ring starts overwriting unread slots? Also, my section question was: (2) What is the benefit of NETMAP_DO_RX_POLL? I do see the slots being updated when I set this flag but 'tail' is not advancing unless I read. Basically, all I am trying to do is detect if frames are dropped in my application using netmap API. Thanks! B.
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