Firefox consumes 100% CPU while polling

[Matthias Schmidt]

Hi,

I compiled a new version of Firefox from pkgsrc (3.6.11) and after some
time Firefox consumes 100% CPU even if only one empty tab is open.

The machine runs

DragonFly hades 2.9-DEVELOPMENT DragonFly v2.9.0.90.g20134-DEVELOPMENT
#0: Sun Oct 31 08:56:28 CET 2010
matthias at hades:/usr/obj/usr/src/sys/T42  i386

and is a UP machine.

Precisely the CPU is consumed by the xulrunner process.  Truss revealed
the following repeating pattern:

poll(0x2b332ab8,0x3,0xffffffff)                  = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3,0xffffffff)                  = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3,0xffffffff)                  = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3,0xffffffff)                  = 209 (0xd1)
poll(0x2b332ab8,0x3,0xffffffff)                  = 209 (0xd1)
poll(0x2b332ab8,0x3,0xffffffff)                  = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3)                             = 209 (0xd1)
poll(0x2b332ab8,0x3,0xffffffff)                  = 1 (0x1)
read(0x9,0xbfbfea9f,0x1)                         = 3 (0x3)
gettimeofday(0xbfbfebcc,0x0)                     = 0 (0x0)
write(8,0x290ca7e1,1)                            = 4 (0x4)
gettimeofday(0xbfbfeb9c,0x0)                     = 0 (0x0)
gettimeofday(0xbfbfeb6c,0x0)                     = 116 (0x74)
gettimeofday(0xbfbfebec,0x0)                     = 0 (0x0)
read(0x3,0x2a200018,0x1000)                      = 3 (0x3)
poll(0x2b332ab8,0x3,0x0)                         = 0 (0x0)
gettimeofday(0xbfbfebec,0x0)                     = 116 (0x74)
read(0x3,0x2a200018)                             ERR#35 'Resource
temporarily unavailable'

A longer output is available here:
http://leaf.dragonflybsd.org/~matthias/truss_ff.txt

It looks similar to issue1886, but that's a wild guess.

Cheers

	Matthias