Re: [RFC][PATCH] perf tools: Merge trace.info content intoperf.data

From: Ingo Molnar
Date: Wed Oct 07 2009 - 02:23:55 EST



* Frederic Weisbecker <fweisbec@xxxxxxxxx> wrote:

> Hi,
>
> Here is an attempt to remove the trace.info file. It works well for
> me, the reason for it to be an RFC is that I have doubts about the
> backward compatibility.
>
> A file created by perf after his patch is unsupported by previous
> version because the size of the headers have increased.

That's OK i think in terms of trace.info - trace.info was a temporary
hack to begin with.

> That said, it's two new fields that have been added in the end of the
> headers, and those could be ignored by previous versions if they just
> handled the dynamic header size and then ignore the unknow part. The
> offsets guarantee the compatibility.

Yes, that's how it should work.

> But previous versions handle the header size using its static size,
> not dynamic, then it's not backward compatible.
>
> Anyway, I'm not sure exactly how to handle that.

That's a bug in the previous version - mind doing a standalone fix for
that so we can mark it Cc: stable?

Thanks,

Ingo
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