misc/164130: broken netisr initialization

[Robert N. M. Watson]

On 14 Jan 2012, at 22:00, Коньков Евгений wrote:

> also in r222249 next things are broken:
> 
> 1. in net.isr.dispatch = deferred
> 
> intr{swiX: netisr X} always have state 'WAIT'

Thanks for your (multiple) e-mails. I will catch up on the remainder of the thread tomorrow, having returned from travel today, but wanted to point you at "netstat -Q", which will allow you to more directly test what dispatch policy is being implemented. It allows you to directly inspect counters for directly dispatched vs. deferred packets with each netisr thread. Relying on sampled CPU use can be quite misleading, as dispatch policies can have counter-intuitive effects on performance and CPU use; directly monitoring the cause, rather than the effect, would be more reliable for debugging purposes.

Robert


> 
>  PID USERNAME   PRI NICE   SIZE    RES STATE   C   TIME   WCPU COMMAND
>   11 root       155 ki31     0K    32K RUN     1  25:02 87.16% idle{idle: cpu1}
>   11 root       155 ki31     0K    32K CPU0    0  25:08 86.72% idle{idle: cpu0}
>   11 root       155 ki31     0K    32K CPU2    2  24:23 83.50% idle{idle: cpu2}
>   11 root       155 ki31     0K    32K CPU3    3  24:47 81.93% idle{idle: cpu3}
>   12 root       -92    -     0K   248K WAIT    3   0:59  6.54% intr{irq266: re0}
> 3375 root        40    0 15468K  6504K select  2   1:03  4.98% snmpd
>   12 root       -72    -     0K   248K WAIT    3   0:28  3.12% intr{swi1: netisr 1}
>   12 root       -60    -     0K   248K WAIT    0   0:34  1.71% intr{swi4: clock}
>   12 root       -72    -     0K   248K WAIT    3   0:27  1.71% intr{swi1: netisr 3}
>   12 root       -72    -     0K   248K WAIT    1   0:20  1.37% intr{swi1: netisr 0}
>    0 root       -92    0     0K   152K -       2   0:30  0.98% kernel{dummynet}
>   12 root       -72    -     0K   248K WAIT    3   0:13  0.88% intr{swi1: netisr 2}
>   13 root       -92    -     0K    32K sleep   1   0:11  0.24% ng_queue{ng_queue3}
>   13 root       -92    -     0K    32K sleep   1   0:11  0.10% ng_queue{ng_queue0}
>   13 root       -92    -     0K    32K sleep   1   0:11  0.10% ng_queue{ng_queue1}
> 
> 
> 2. There is no cpu load differences between dispatch methods. I have
> tested two: direct and deferred (see on picture)
> 
> http://piccy.info/view3/2482121/cc6464fbe959fd65ecb5a8b94a23ec38/orig/
> 
> 'deferred' method works same as 'direct' method!
> 
>