Interrupt Descriptions

[John Baldwin]

On Wednesday 30 September 2009 8:02:57 pm Bruce Evans wrote:
> On Wed, 30 Sep 2009, John Baldwin wrote:
> 
> > A few folks have asked recently for the ability to add descriptive strings to
> > registered interrupt handlers.  This is especially true since the advent of
> > MSI with multiple interrupts per device.  I hacked up a prototype today that
> 
> Interrupt names should be no longer than 4 (5 works sometimes) characters so
> that they can be displayed by systat -v.

For the machines this is targeted at (i.e. ones with devices using MSI/MSI-X)
the number of interrupts is already well beyond what systat -v can currently
display anyway.  I believe most folks use vmstat -i or ithread stats in top
to measure real-time interrupts at this point.  Possibly systat could grow a
new interrupt-only mode that has sufficient room for full interrupt names.

FYI, it actually looks decent enough running a 7.x systat on a test 9.0 kernel:

                                     25000 frevn          pdpgs  2000 cpu0: time
                                                          intrn       igb0:tx 0
Disks   da0 pass0                                  473896 wire     25 igb0:rx 0
KB/t   0.00  0.00                                   13872 act         igb0:link
tps       0     0                                   10080 inact       igb1:tx 0
MB/s   0.00  0.00                                     128 cache     1 igb1:rx 0
%busy     0     0                                 7603460 free        igb1:link

For these devices with MSI, the description (tx 0, tx 1, link, etc.) is
actually more meaningful than the IRQ.

-- 
John Baldwin