Re: [RFC][PATCH] 1/3] [XEN] Use explicit bit sized fields for exported xentrace data.

[Keir Fraser <keir@xensource.com>]

On 1/12/06 5:54 pm, "George Dunlap" <dunlapg@umich.edu> wrote:

> Variable-length trace buffers would certainly be nice.  Right now, for
> some records, I'm squeezing bits into things, and just *one* more byte
> would be great... but for other records, I'm storing 4 words of 0, and
> there just doesn't seem to be any other useful information to add.
> 
> Keir, is the simpler, "one trace size fits all" method just because it
> was easier to implement originally, or is the simplicity expected to
> greatly reduce overhead and/or bugginess?  If the former, then there
> seems enough interest in making the tracing more flexible to be worth
> changing; if the latter, then we should probably chose something and
> live with it, or perhaps a compromise (i.e., two record sizes).

There's no reason not to make the trace format more flexible. There's a
question about how you represent trace points in the Xen code though, when
the format is no longer a list of fixed size integers.

 -- Keir