Date: Mon, 27 Jun 2011 19:09:25 +0200 From: Luigi Rizzo <rizzo@iet.unipi.it> To: net@freebsd.org Subject: RTL8169 (if_re) poor tx packet rate ? Message-ID: <20110627170925.GA2920@onelab2.iet.unipi.it>
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Asking just in case someone has experience on the sending rate with Realtek 8168/8169/8110 Gbit cards. On the receive side, using netmap, even with the CPU at 200 MHz the card seems able to receive 1.38 Mpps (the most i can generate with my other, intel 1 Gbit/s cards). But on the receive side the most i get is 370 Kpps (with 64-byte packets), and achieve slightly faster speeds (390Kpps) only sending shorter frames (16 bytes) and relying on the padding inserted by the card. Even the standard drivers reach similar speeds (in the 300Kpps range). I have tried to change several configuration parameters in the NIC settings (tx dma threshold, mitigation, checked the inter-packet gap, increasing the ring size to 1024) but they seem to have no effect. The only improvement (but a very modest one) is if i use the "high priority" tx ring instead of the regular one -- then speed goes up from 365 to 370 Kpps (very reproducible). At much larger packet sizes (1024 and above) the card does line rate with no problems. Has anyone tried to push these cards at high speed, or do you have suggestions on what to try ? cheers luigi http://info.iet.unipi.it/~luigi/netmap/
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