Re: kern/53591: [system] process uses >400% CPU on idle machine

[Andreas Gustafsson <gson%gson.org@localhost>]

The following reply was made to PR kern/53591; it has been noted by GNATS.

From: Andreas Gustafsson <gson%gson.org@localhost>
To: coypu%sdf.org@localhost
Cc: gnats-bugs%NetBSD.org@localhost
Subject: Re: kern/53591: [system] process uses >400% CPU on idle machine
Date: Tue, 11 Sep 2018 12:13:21 +0300

 coypu%sdf.org@localhost wrote:
 >  Could this be related?
 >  (I don't know how to check)
 >  
 >  https://v4.freshbsd.org/commit/netbsd/src/pKELGaMpgIjnUoLA
 
 I don't think so.  I ran a kernel profile using dtrace:
 
   dtrace -x stackframes=100 -n 'profile-99 /arg0/ { @[stack()] = count(); }'
 
 and pserialize did not show up at all.  Most of the time was spent in
 the idle loop and xc_thread, and then there was this stack trace
 which: looks like it could be the source of the xcalls:
 
               netbsd`xc_wait+0x3a
               netbsd`pool_cache_invalidate+0xd7
               netbsd`pool_reclaim+0x58
               netbsd`pool_drain+0x60
               netbsd`uvm_pageout+0x4bf
               netbsd`lwp_trampoline+0x17
 
 -- 
 Andreas Gustafsson, gson%gson.org@localhost