Date: Fri, 30 Mar 2018 04:00:15 +0000 From: Ming Fu <Ming.Fu@esentire.com> To: "freebsd-net@freebsd.org" <freebsd-net@freebsd.org> Subject: netmap: How the buf_num of buffers is used by driver and monitor app Message-ID: <abc1c7da14d64c04bdce467825d0af44@mbx01cmb01p.esentire.local>
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Hi, I am wondering about the netmap module parameters buf_num. The default buf_= num 163840 seems fairly big compare to intel 10G ixgbe of max 4096 queue si= ze. A full queue of the interface can only use a very small portion of the = buf_num. Can the netmap enabled driver like ixgbe use more buffers than the= "ethtool -G" configured rx/tx queue size? I need to feed packages captured from netmap device to a few traffic monito= rs on the same box. The monitor application attach to the device as netmap = monitor with the /r at the end of device name. My question is if the primar= y read of the device calls poll(), the netmap buffer is synced with the ker= nel. Can the other monitor application still access the packet that the pri= mary read just returned to the kernel? If one of the monitor on the netmap = device is slow, will it cause trouble for the primary reader and other moni= tors? How can I cache a lot of packets in the buffer in case one of the mon= itor application had a temporary slow down? Thanks, Ming
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