Re: [patch 1/6] statistics infrastructure - prerequisite: scatter-gather ringbuffer

From: Andi Kleen
Date: Wed Dec 14 2005 - 22:33:09 EST


> Relayfs seems to be the right thing to convey streams of incremental
> pieces of data, like trace records as implemented by
> arch/s390/kernel/debug.c, for example. Relayfs would work for statistics
> that involve data growth like a history of a counter, for example, or
> the raw measurement data reported for statistic updates. I doubt it is
> the right thing for counters, fill level indicators and histograms;

For those we traditionally use ASCII files if the data is small.
If it's big relayfs is probably the right answer.

> basically for all types of statistics that do not continuously put their
> hands on untouched memory to store their results.
>
> I am currently using debugfs, which works fine for all of these cases.
> In addition, I need some ringbuffer functionality, though.

IIRC relayfs was changed to be able to handle files in debuggfs by
just plugging in the file operations.

-Andi
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