Intel 82574L Gigabit Ethernet Controller

[Ian Smith]

On Fri, 9 Jul 2010, Ryan Stone wrote:

 > No, defining EM_WATCHDOG as 10 * hz should mean that the watchdog
 > expires after 10 seconds no matter what your kern.hz is.  hz is set to
 > the number of ticks in a second.

Ok, one more probably wild punt .. Shtorm you say HZ=4000, giving:

===
And here is vmstat -i
interrupt                          total       rate
irq16: uhci0                        2673          2
irq18: ehci0 uhci5                     2          0
irq19: uhci2 uhci4                    70          0
irq23: uhci3 ehci1                  8835          9
cpu0: timer                      3743479       3957
irq256: em0                       662219        700
irq257: em0                       717531        758
irq259: em0                        12142         12
irq260: em0                         6100          6
irq261: em1                       694169        733
irq262: em1                       217388        229
irq264: em1                       463023        489
irq265: em1                           11          0
cpu1: timer                      3743411       3957
cpu6: timer                      3743408       3957
cpu7: timer                      3743407       3957
cpu4: timer                      3743408       3957
cpu5: timer                      3743407       3957
cpu3: timer                      3743408       3957
cpu2: timer                      3743409       3957
Total                           32731500      34599
===

a little more variant from 4000 than expected?  Originally:

===
but vmstat -i shows only one pair is used
%vmstat -i
interrupt                          total       rate
irq1: atkbd0                         391          0
irq18: ehci0 uhci5                     2          0
irq19: uhci2 uhci4                    27          0
irq23: uhci3 ehci1                  8463          0
cpu0: timer                    107412943       7864
irq256: em0                     93311951       6832
irq257: em0                     90479067       6624
irq260: em0                            2          0
irq261: em1                     92966894       6806
irq262: em1                     80298240       5879
irq265: em1                            1          0
cpu1: timer                    107412607       7864
cpu2: timer                    107412785       7864
cpu3: timer                    107412830       7864
cpu5: timer                    107413210       7864
cpu4: timer                    107413389       7864
cpu7: timer                    107407337       7864
cpu6: timer                    107413132       7864
Total                         1216363271      89058
===

Was that with HZ=8000 ?  Or what?  In any case, em interrupt rates were 
a whole lot higher then - but maybe it was just a lot busier on the net?

HZ=4000 ticks are 250ns, not 25ms.

Seems like you're not lacking horsepower .. unless you're using POLLING 
(not indicated) or, say, dummynet pipes needing finer-grained output 
queue scheduling, it might be worth trying the default HZ=1000 ?

Just curious along similar lines: what says sysctl kern.timecounter ?

cheers, Ian