SCHED_ULE / NetGraph interaction broken somwhere between r227874 and r229818

[Lev Serebryakov]

Hello, Andriy.
You wrote 12 января 2012 г., 13:54:41:

>>  Switching to 4BSD helps. 4BSD works as usual: all CPU time is
>>  interrupts and network thread, system is responsive under heaviest load,
>>  normal operations of DNS, DHCP and hostapd.
> How reproducible is this result?
  100%

> In other words, have you definitely ruled out all other factors besides the
> scheduler?

   I have two almost-identical NanoBSD images which differs in one line in kernel
 config  -- option about scheduler. Worlds are exactly the same, only kernels were
 rebuilt.

      Alexander Motin suggests, that switching scheduler could slightly
 change stack consumption, which triggers switching to ng_queue
 instead of direct calls.

    Really, here is diff between "md5" of all files of one and other
 images:

blob# diff  ~lev/bsd-image.md5sums ~lev/ule-image.md5sums
74c74
< MD5 (./boot/kernel/kernel) = 3bb0dd757628b5065d27ee5e7fc22eb3
---
> MD5 (./boot/kernel/kernel) = 5ba379d2c73e1277566f4bbcb618a9f2
618c618
< MD5 (./conf/base/var/log/userlog) = a827af82c1f780687706b19c7d94b29e
---
> MD5 (./conf/base/var/log/userlog) = fc289b66ae6cb23f9b24b694bf12157b
15678c15678
< MD5 (./var/log/userlog) = a827af82c1f780687706b19c7d94b29e
---
> MD5 (./var/log/userlog) = fc289b66ae6cb23f9b24b694bf12157b

-- 
// Black Lion AKA Lev Serebryakov <lev at FreeBSD.org>