> Hi. > When the current dsched policy is set to fq, the console (or ssh > connection) > occasionally freezes (becomes unresponsive, even to ctrl+T). However, > I can still switch between ttyvN terminals by pressing Alt+Fn keys, > and drop to DDB (I remember reading a similar description in the past, > but I couldn't find the message in my mailbox). > > Unfortunately, the kernel dumping locks up too in that case > (no progress is printed on the screen), so no vmcore is available > at the moment. FWIW, dsched_fq is loaded as kernel module and the policy > is set via /etc/rc.d/sysctl. > > This is on an Atom D510 with 4G bytes of RAM and running a very recent > -DEVELOPMENT x86_64 kernel; I haven't tried it on a PC running 32-bit > version yet. >
I wonder if this: http://leaf.dragonflybsd.org/mailarchive/bugs/2010-10/msg00085.html is related, I did enable DSCHED_FQ via sysctl just before I ran "hammer cleanup" I remember now, and the symptoms are same - freeze but can switch between terminals, but can't actually execute any command because they are all "hanging", for about 5 minutes and eventually freeze completely but without a kernel dump. Petr
