CPU underload

[Eugene Grosbein]

On 01.11.2015 01:11, Adrian Chadd wrote:
> Hi,
> 
> I don't see any DELAY in my testing, nor MipsUserIntr, so yeah, I must
> be doing something different.

I've removed options HWPMC_MIPS_BACKTRACE from the kernel and now
pmcstat shows no MipsUserIntr and I've got full CPU load for same
inter-vlan bridging test:

# vmstat 1
procs  memory      page                       disks     faults         cpu
r b w  avm   fre   flt  re  pi  po    fr   sr fl0 md0   in    sy    cs us sy id
0 0 0  85M   74M    86   0   1   0    66    3   0   0 2633  3117   223  2 40 57
0 0 0  85M   74M     0   0   0   0     0    3   0   0 5049   116   858  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5896   111   738  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 6115   111   687  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 3789   118   499  0 100 0
0 0 0  85M   74M     0   0   0   0     0    3   0   0 3789   111   592  1 99  1
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5474   111   689  1 98  1
0 0 0  85M   74M     0   0   0   0     0    3   0   0 5234   111   762  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 4810   111   648  0 99  1
0 0 0  85M   74M     0   0   0   0     0    3   0   0 4884   111   653  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 4914   111   629  1 99  1
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5679   111   713  0 100 0
0 0 0  85M   74M     0   0   0   0     0    3   0   0 4417   111   698  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 6107   118   621  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   1 4251   111   594  0 100 0
0 0 0  85M   74M     0   0   0   0     0    3   0   0 6050   111   747  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 4487   111   698  0 99  1
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5104   111   624  0 100 0
0 0 0  85M   74M     0   0   0   0     0    3   0   0 4762   115   818  0 99  1
0 0 0  85M   74M     0   0   0   0     0    6   0   0 6223   111   706  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 6020   111   719  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5950   111   818  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5373   118   761  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5488   111   729  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 5527   117   691  0 100 0
0 0 0  85M   74M     0   0   0   0     0    3   0   0 6637   119   916  0 100 0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 3980   111   634  1 99  0
0 0 0  85M   74M     0   0   0   0     0    6   0   0 6396   111   932  0 100 0

However, speed is still no more than 59,5MByte/s.

Does arge(4) driver support DEVICE_POLLING?
When CPU is overloaded with interrupts, userland has no cycles to run.