Unresponsive after dtrace

John Birrell jb at what-creek.com
Mon Sep 1 01:52:59 UTC 2008

On Sun, Aug 31, 2008 at 06:35:16AM -0500, Wes Morgan wrote:
> I know this has been reported already, but I want to give a "me too". 
> After installing a new world and kernel from the tree yesterday afternoon, 
> I let my system run all night. This morning everything was extremely 
> sluggish and unresponsive. According to top, which I thankfully left 
> running, processes were going in and out of "*kmem_" (obviously 
> truncated). CPU usage was 80+% system and load averages were around 5.4. 
> The only changes I made to my system besides upgrading were to include the 
> options KDB, DDB and STACK in my kernel for zfs functionality. 
> Unfortunately, I cannot try without those options since my root is zfs. 
> Booting a kernel from 8/20 works fine.

Wes, will you please try removing "#define KMEM_DEBUG" from:


This is the likely cause of the performance problems you are seeing. It
is also the reason why you needed to add DDB, DBB and stack to the kernel.

The quickest way to try this is to just build the 'opensolaris' kernel module:

(keep a copy of your current /boot/kernel)
cd src/sys/modules/opensolaris
make obj && make depend && make all && make install

John Birrell

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