Re: [PATCH 6/18] 2.6.17.9 perfmon2 patch for review: samplingformat support

From: Andrew Morton
Date: Fri Sep 01 2006 - 14:12:51 EST


On Fri, 1 Sep 2006 09:09:25 -0700
Stephane Eranian <eranian@xxxxxxxxxx> wrote:

> > Why identify a format with a UUID rather than via a nice human-readable name?
> >
>
> Although a UUID is slightly more difficult to manipulate than a clear text string, it
> offers several advantages:
> - is guaranteed unique
> - generation is fully distributed
> - easy generation with uuidgen
> - fixed size
> - very easy to pass to the kernel, there is not char * in a struct pass to kernel
> - not to worry about '\0'

The kernel has got along OK using ascii strings for this sort of thing in
thousands of places for many years. Is there something special or unique
about perfmon's requirements which make UUIDs a clearly superior
implementation?

> We use UUID to idenitfy a format + a version number. The version number can be useful
> to identify backward compatible versions of a format.

Interfaces use major and minor version numbering for that.
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