[PATCH] possible fix for the runtime going backwards warnings

[Patrick Bowen]

John Baldwin wrote:

>On Tuesday 21 February 2006 21:36, Kris Kennaway wrote:
>  
>
>>On Tue, Feb 21, 2006 at 10:47:04AM -0500, John Baldwin wrote:
>>    
>>
>>>The latest round of calcru() changes accidentally changed calccru() to
>>>use the wrong rusage_ext structure (p->p_rux vs p->p_crux) when
>>>calculating usage times for children.  The patch fixes calccru() to use
>>>p->p_crux again.  It also moves the ruadd() in exit1() even later in the
>>>function so that it takes the dying thread's last time slice into
>>>account.  Please test it and let me know if it makes the messages go away
>>>(or if it makes things worse!)  Thanks!
>>>
>>>http://www.FreeBSD.org/~jhb/patches/calccru.patch
>>>      
>>>
>>I think you committed this already, right?
>>    
>>
>
>Yes.
>
>  
>
>>I'm still getting calcru spam on the 3 SMP machines that I upgraded
>>with fresh sources:
>>    
>>
>
>Is it more or less than before the patch?  Also, what happens if you just back 
>out the kern_exit.c change?
>
>  
>
>>   Working revision:    1.284   Wed Feb 22 00:27:32 2006
>>   Repository revision: 1.284   /c/ncvs/src/sys/kern/kern_exit.c,v
>>
>>   Working revision:    1.155   Wed Feb 22 00:27:33 2006
>>   Repository revision: 1.155   /c/ncvs/src/sys/kern/kern_resource.c,v
>>
>>calcru: runtime went backwards from 140475 usec to 140458 usec for pid 724
>>(csh) u 9:54457/54961 s 14:86017/85496 i 0:1/1
>>calcru: runtime went backwards from 3855 usec to 3854 usec for pid 719
>>(csh) u 0:0/0 s 1:3855/3854 i 0:0/0
>>calcru: runtime went backwards from 19044 usec to 19043 usec for pid 713
>>(tcsh) u 2:8888/12695 s 1:10156/6347 i 0:0/1
>>calcru: runtime went backwards from 41540 usec to 41531 usec for pid 454
>>(nfsd) u 4:27693/27687 s 2:13846/13843 i 0:1/1
>>calcru: runtime went backwards from 4552 usec to 4551 usec for pid 452
>>(mountd) u 0:0/0 s 1:4552/4551 i 0:0/0
>>calcru: runtime went backwards from 564 usec to 563 usec for pid 140
>>(adjkerntz) u 0:0/0 s 1:564/563 i 0:0/0
>>calcru: runtime went backwards from 78654 usec to 78637 usec for pid 20
>>(swi6: task queue) u 0:0/0 s 0:0/0 i 4:78654/78637
>>calcru: runtime went backwards from 38428 usec to 38420 usec for pid 0
>>(swapper) u 0:0/0 s 11:38428/38420 i 0:0/0
>>
>>
>>calcru: runtime went backwards from 1496715 usec to 1496579 usec for pid 32
>>(pagezero) u 0:0/0 s 199:1496715/1496579 i 0:0/0
>>calcru: runtime went backwards from 102337 usec to 102327 usec for pid 0
>>(swapper) u 0:0/0 s 41:102337/102327 i 0:0/0
>>
>>
>>calcru: runtime went backwards from 1461648 usec to 1461600 usec for pid 32
>>(pagezero) u 0:0/0 s 194:1461648/1461600 i 0:0/0
>>calcru: runtime went backwards from 100852 usec to 100848 usec for pid 0
>>(swapper) u 0:0/0 s 42:100852/100848 i 0:0/0
>>    
>>
>
>The pagezero ones are truly odd.  calcru() shouldn't be called for kthreads 
>very often (if at all).  I wonder if your tickrate is changing out from under 
>you.  Try editing sys/i386/i386/tsc.c and where it does 'set_cputicker(rdtsc, 
>tsc_freq, 1)' change the last parameter to '0' and see if they go away.
>
>  
>
Mr. Baldwin:

I installed your patch, did a "make kernel KERNCONF=GENERIC" and got 
fewer calcru messages (down form about 10-12 to 1-2).
After changing the set_cputicker(...) parameter to "0", I got none!

Copyright (c) 1992-2006 The FreeBSD Project.
Copyright (c) 1979, 1980, 1983, 1986, 1988, 1989, 1991, 1992, 1993, 1994
        The Regents of the University of California. All rights reserved.
FreeBSD 7.0-CURRENT #1: Wed Feb 22 17:05:16 CST 2006
    pbowen at sg1.sgc.org:/usr/obj/usr/src/sys/GENERIC
WARNING: WITNESS option enabled, expect reduced performance.
Timecounter "i8254" frequency 1193182 Hz quality 0
CPU: Intel Pentium III (601.37-MHz 686-class CPU)
  Origin = "GenuineIntel"  Id = 0x68a  Stepping = 10
  
Features=0x383f9ff<FPU,VME,DE,PSE,TSC,MSR,PAE,MCE,CX8,SEP,MTRR,PGE,MCA,CMOV,PAT,PSE36,MMX,FXSR,SSE>

Thanks,
Patrick

P.S. Sorry for the late reply. My SMTP server was having some problems, 
or something...