On Fri, 16 Nov 2007, Igor Sysoev wrote:
The attached patch creates the following bge loader tunables:
I plan to commit old work to do this using sysctls. Tunables are harder to use and aren't needed since changes to the defaults aren't needed for booting. I also implemented dynamic tuning for rx coal parameters so that the sysctls are mostly not needed. Ask for patches if you want to test this extensively.
hw.bge.rxd=512 Number of standard receive descriptors allocated by the driver. The default value is 256. The maximum value is 512.
I always use 512 for this. The corresponding value for jumbo buffers is hard-coded (JSLOTS exists to tune the value at config time, like SSLOTS does for this, but is no longer used). Only machines with a small amount of memory should care about the wastage from always allocating the max number of descriptors.
hw.bge.rx_int_delay=500 This value delays the generation of receive interrupts in microseconds. The default value is 150 microseconds.
This is a good default. I normally use 100 (goes with dynamic tuning to limit the rx interrupt rate to 10 kHz).
hw.bge.tx_int_delay=500 This value delays the generation of transmit interrupts in microseconds. The default value is 150 microseconds.
I use 1 second. Infinity works right, except it wastes mbufs when the tx is idle for a long time.
hw.bge.rx_coal_desc=64 This value delays the generation of receive interrupts until specified number of packets will be received. The default value is 10.
64 is a good default. 10 is a bad default (it optimizes too much for latency at a cost of efficiency to be good). I use 1 when optimizing for latency. Dynamic tuning sets this to a value suitable for limiting the rx interrupt rate to a specified frequency (10 kHz is a good limit).
hw.bge.tx_coal_desc=128 This value delays the generation of transmit interrupts until specified number of packets will be transmited. The default value is 10.
128 is a good default. I use 384. There are few latency issues here, so the default of 10 mainly costs efficiency. Bruce _______________________________________________ freebsd-net@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-net To unsubscribe, send any mail to "[EMAIL PROTECTED]"
