100% cpu utilization

Scott Moomaw scott at bridgewater.edu
Tue Nov 6 07:41:07 GMT 2001

I've just watched the system climb to 100% cpu utilization again and may
have caught some helpful info.  We're running the latest CVS on a Solaris
8 x86 box.  Looking at things this time, it may be that the select
processing in sys_select is overwhelming the system under heavier loads.
It appears that Solaris uses poll() as the underlying method of
implementing the select() call.  This morning, I saw approximately 170
smbd processes active when the problem occurred.  Every one that I was
able to get a pstack from was in a state similar to this.

22808:  /usr/local/samba/bin/smbd -D
 dfa19095 poll     (80478c0, 3, ea60)
 dfa2bee5 select   () + 1f5
 08132133 sys_select (d, 8047a2c, 8047a24, 80a12f9) + c7
 080a1395 receive_message_or_smb (8210991, 10040, ea60, 80a25e0) + 169
 080a261a smbd_process (dfbed1e8, 8047b00, 8047be8, 210, dfa0d67f, dfa0d6a3, dfbe137f, 8047b00, ...) + 11e
 0806ee59 main     (2, 8047b44, 8047b50) + 6d9
 0806d94f _start   () + 57

Top reports extremely high kernel utilization of the CPU.  Anyone have
knowledge of the efficiency of Solaris's poll() system call?  It seems
like the number of processes in a poll() state is more than the system can
handle.  The system is a dual P400 and didn't exhibit this symptom until
after our Win2k/Samba 2.2.x upgrades this summer.

Your thoughts???


On Tue, 6 Nov 2001, David Collier-Brown wrote:

> Jeremy Allison wrote:
> > What is in the log for this smbd ? Why is it shutting down ?
> 	Scot, can you dig out a log?
> --dave
> --
> David Collier-Brown,           | Always do right. This will gratify
> Americas Customer Engineering, | some people and astonish the rest.
> SunPS Integration Services.    |                      -- Mark Twain
> (905) 415-2849                 | davecb at canada.sun.com

 Scott Moomaw, Network Administrator              Scott at Bridgewater.edu
 Bridgewater College, IT Center
 Bridgewater, VA  22812
 Phone (540) 828 - 8000  x5437              FAX:  (540) 828 - 5493

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