Re: [Xen-devel] Scheduler stats and some doubts

[Jean Guyader <jean.guyader@xxxxxxxxx>]

Hi,

2009/9/12 Marco Tizzoni <marco.tizzoni@xxxxxxxxx>:
> Hello,
> someone can tell me how to enable scheduler statistics and how to display 
> them?
>
> I found this comment:
>
> ---------------------------------------
> /*
>  * CSCHED_STATS
>  *
>  * Manage very basic per-vCPU counters and stats.
>  *
>  * Useful for debugging live systems. The stats are displayed
>  * with runq dumps ('r' on the Xen console).
>  */
> #ifdef PERF_COUNTERS
> #define CSCHED_STATS
> #endif
> ---------------------------------------
>
> I've just enabled this in Rules.mk:
> ---------------------------------------
> verbose       ?= y
> perfc         ?= y
> perfc_arrays  ?= y
> ---------------------------------------
>
> now xenperf works but I don't know how to access the "Xen console".
>

The perf counters are a debug key. You can access the xen console via serial
by doing CTRL+A-CTRL+A, then h. You might need to enable debug
for perf counters.

You can also invoke a debug key using xm directly.

Jean

> Also, not related to this issue, I'm interested in accounting how many
> ticks the net backend driver spends in rx/tx.
> Can it make sense using the getrusage() function at start/end of
> net_rx_action()/net_tx_action() or it can lead to unconsistent
> accounting?
>
> Is there a better way?
>
> Any suggestions are welcome.
>
> Thanks in advance.
> Marco
>

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