NtQuerySystemInformation needs a little bit more flesh for SystemProcessorPerformanceInformation

[Paul Vriens]

Hi,

I was trying out the latest SysInternals Process Explorer and it struck 
me that the overall CPU % stayed at 0.

Adding some values to the sppi structure fixed this but I'm just 
wondering what values to use:

sppi[cpus-1].Reserved1[0].QuadPart   = (ULONGLONG)remainder[0] * 
10000000 / clk_tck;

This Reserved1[0] is the DPC Time but I'm wondering what values from 
/proc/stat to use here (remainder[0] is I/O wait). We could always make 
up something of course but being accurate would be nicer.

[Juan Lang]

> This Reserved1[0] is the DPC Time but I'm wondering what values from
> /proc/stat to use here (remainder[0] is I/O wait). We could always make up
> something of course but being accurate would be nicer.

DPC Time has no equivalent in /proc/stat.  It's an NT thing.  Making
something up is the only appropriate thing, unless we start doing
something special with DPCs someday.
--Juan

[Paul Vriens]

On 07/28/2011 08:31 PM, Juan Lang wrote:
> > This Reserved1[0] is the DPC Time but I'm wondering what values from
> > /proc/stat to use here (remainder[0] is I/O wait). We could always make up
> > something of course but being accurate would be nicer.
>
> DPC Time has no equivalent in /proc/stat.  It's an NT thing.  Making
> something up is the only appropriate thing, unless we start doing
> something special with DPCs someday.
> --Juan

Thanks Juan.

Making something up turns out to be easy but the result is not good 
enough yet. I first want to find out how the whole cpu usage is 
calculated in some of the tools.

Having a number in the overall cpu usage is nice but it should be close 
to what it should be in this case.