9.1 callout behavior

[John Baldwin]

On Tuesday, September 16, 2014 04:17:20 PM Adrian Chadd wrote:
> Hi!
> 
> I know this is bringing up an old thread, but Dell has shipped us some
> hardware (thanks Dell!) and I'm helping them take a look at it.
> 
> On 10 December 2013 07:23, Alexander Motin <mav at freebsd.org> wrote:
> > On 10.12.2013 17:12, Bret Ketchum wrote:
> >>      Do either of you have a dual socket/package motherboard to play
> >> 
> >> with? I've tried a couple single socket motherboards and cannot
> >> reproduce the issue. I'm wondering if this occurs on only multi-socket
> >> mobos.
> > 
> > My main test system is dual-socket (Supermicro X8DTU).
> 
> It's reasonably reproducable.
> 
> The tscdrift tool from jhb (in tools/tools/tscdrift) looks thus:
> 
> root at appollyon:~/src/tscdrift # ./tscdrift
> 
> CPU | TSC skew (min/avg/max/stddev)
> 
> ----+------------------------------
> 
>   0 |     0     0     0    0.000
>   1 |    34    79   380   39.005
>   2 |   306   476  1326   120.472
>   3 |   306   485  1426   123.487
>   4 |   280   473  7500   248.965
>   5 |   280   462  1320   126.691
>   6 |   300   461  1934   129.362
>   7 |   300   470  1354   122.654
>   8 |   292   420  3640   152.029
>   9 |   135   190   655   58.601
>  10 |   112   188   620   56.490
>  11 |   114   189   660   62.440
>  12 |   129   204   566   53.731
>  13 |   129   206   617   56.047
>  14 |   126   211   620   54.450
>  15 |   126   213   603   54.808
>  16 |   440   590  1683   217.649
>  17 |   440   612  1606   234.295
>  18 |   468   642  4017   266.768
>  19 |   463   653  8683   352.624
>  20 |   480   671  1500   255.395
>  21 |   480   689  8060   348.384
>  22 |   468   707  3766   296.721
>  23 |   466   703  1683   284.625
>  24 |   480   767  8183   373.741
>  25 |   486   782  7400   362.069
>  26 |   480   664  1620   249.125
>  27 |   477   686  3669   278.144
>  28 |   469   621  1897   226.673
>  29 |   469   649  8275   363.575
>  30 |   457   636  1835   250.005
>  31 |   451   641  4300   272.322

FYI, that looks fairly typical for a system whose TSC's are in sync in my 
experience.  Is this a dual-package system?  The fact that threads 9-15 are 
"closer" to 0 than 2-8 is a bit unusual, but the rest looks quite typical.

-- 
John Baldwin