On Tue, Apr 16, 2013 at 1:56 PM, Bruce Evans <b...@optusnet.com.au> wrote: > > Technical bugs include: > - wrong defaults are claimed for *coal_ticks. The defaults are 150, but > are claimed to be 150 milliseconds. These values are dimensionless, > but since ticks take 1 microsecond each, 150 gives 150 microseconds, > not 150 milliseconds.
The real effect of TX coalesce ticks is confusing to me; TX interrupt does not come at the rate you have specified, at least for several PCI-e bge(4) I have tested. However, RX coalesce ticks work as expected. Here is how the tests were conducted: - Send only test, no RX - Each packet consume only one BD; UDP datagram, using hardware checksum offloading - TX coalesce BDs is set to 0, so only TX coalesce ticks have effect The interrupt rate I had got seemed to be related to packet size?! I had tested two TX coalesce ticks settings: (the result I had recorded was using BCM5720) The first setting was 1023us; the first col is UDP data size, the second col is rough interrupt rate 18B 667/s 64B 611/s 128B 538/s 256B 432/s 512B 311/s 1024B 194/s 1472B 146/s Tecond setting was 128us; the first col is UDP data size, the second col is rough interrupt rate 18B 1647/s 64B 1338/s 128B 1030/s 256B 700/s 512B 430/s 1024B 235/s 1472B 169/s Well, to be frank, it does not make too much sense to me. I also twisted the HCC_MODE CLRTICK_TX a bit, but didn't get determined result. (davidch is CC'd) Best Regards, sephe -- Tomorrow Will Never Die _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "freebsd-net-unsubscr...@freebsd.org"
