Date: Wed, 19 Nov 2014 11:23:29 -0800 From: Adrian Chadd <adrian@freebsd.org> To: Hans Petter Selasky <hps@selasky.org> Cc: Lawrence Stewart <lstewart@freebsd.org>, FreeBSD Current <freebsd-current@freebsd.org>, Luigi Rizzo <rizzo@iet.unipi.it>, Navdeep Parhar <np@freebsd.org> Subject: Re: [RFC] Removal of M_FLOWID flag from m_flags [WAS: Add support for hardware transmit rate limiting queues] Message-ID: <CAJ-VmokR-diHyDjETwQ8k5koY3cPQ=PHtfeqpkC7rHyrZb1FTQ@mail.gmail.com> In-Reply-To: <546CE948.2070105@selasky.org> References: <546CE948.2070105@selasky.org>
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Hm, how are we going to have the RSS stuff work at the same time as the hardware flow steering stuff you're prototyping? -adrian On 19 November 2014 11:02, Hans Petter Selasky <hps@selasky.org> wrote: > Hi, > > The M_FLOWID flag is marked as deprecated in the FreeBSD kernel code and the > patch below completely removes it. I suggest we will now be using the > "m_pkthdr.rsstype" also known as "M_HASHTYPE" to decide if the flowid value > is valid or not. When the "rsstype" is set to "M_HASHTYPE_NONE" the > "m_pkthdr.flowid" field is not valid. Else this field contains valid data > for both TX and RX direction. > > Background: > =========== > > The network drivers today use the "rsstype" field only when receiving > traffic. After my patch it is also used when sending traffic, and probably > we should rename it. > > The reason for using the rsstype field for transmit, is to avoid introducing > another field in the MBUF's packet header in order to steer outgoing traffic > into special multiple purpose hardware FIFOs. This new feature should > coexist with the existing flowid mechanism, and this is achieved by > introducing a new hash type which I've named "M_HASHTYPE_HWRING" in my > patch. This type can be selected by upper layers when generating traffic for > lower layers, to indicate that the traffic is of a special kind and should > have special treatment by the hardware, like rate-limiting. Hardware which > doesn't support M_HASHTYPE_HWRING will send out the packets like usual. > > > Patch is available from here: > ============================= > http://home.selasky.org:8192/m_flowid_removal.diff > > > Comments are appreciated! > > > --HPS
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