Date: Thu, 24 Sep 2020 17:31:07 -0400 From: Ryan Stone <rysto32@gmail.com> To: "Scheffenegger, Richard" <Richard.Scheffenegger@netapp.com> Cc: "net@FreeBSD.org" <net@freebsd.org>, "transport@freebsd.org" <transport@freebsd.org> Subject: Re: Socket option to configure Ethernet PCP / CoS per-flow Message-ID: <CAFMmRNxS3CiM4GzVBArXLXga618GnOJhic7QDAk%2BZECdnUVukg@mail.gmail.com> In-Reply-To: <SN4PR0601MB372898DF9D2838392B22C7AF86240@SN4PR0601MB3728.namprd06.prod.outlook.com> References: <SN4PR0601MB372898DF9D2838392B22C7AF86240@SN4PR0601MB3728.namprd06.prod.outlook.com>
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On Fri, Sep 11, 2020 at 12:33 PM Scheffenegger, Richard <Richard.Scheffenegger@netapp.com> wrote: > > Hi, > > Currently, upstream head has only an IOCTL API to set up interface-wide d= efault PCP marking: > > #define SIOCGVLANPCP SIOCGLANPCP /* Get VLAN PCP */ > #define SIOCSVLANPCP SIOCSLANPCP /* Set VLAN PCP */ > > And the interface is via ifconfig <if> pcp <x>. > > However, while this allows all traffic sent via a specific interface to b= e marked with a PCP (priority code point), it defeats the purpose of PFC (p= riority flow control) which works by individually pausing different queues = of an interface, provided there is an actual differentiation of traffic int= o those various classes. > > Internally, we have added a socket option (SO_VLAN_PCP) to change the PCP= specifically for traffic associated with that socket, to be marked differe= ntly from whatever the interface default is (unmarked, or the default PCP). > > Does the community see value in having such a socket option widely availa= ble? (Linux currently doesn't seem to have a per-socket option either, only= a per-interface IOCTL API). > > Best regards, > > Richard Scheffenegger > > _______________________________________________ > freebsd-transport@freebsd.org mailing list > https://lists.freebsd.org/mailman/listinfo/freebsd-transport > To unsubscribe, send any mail to "freebsd-transport-unsubscribe@freebsd.o= rg" Hi Richard, At $WORK we're running into situations where PFC support would be very useful, so I think that this would be a good thing to add. I have a question: does your work also communicate the priority value for an mbuf down to the Ethernet driver, so that it can put the packet in the proper queue?
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