Messages in this thread | | | Date | Thu, 25 Sep 2008 07:33:24 -0700 | From | "Martin Bligh" <> | Subject | Re: [RFC PATCH 1/3] Unified trace buffer |
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> I rather like this idea, as it gives small entries (the common case) the > least overhead but does allow for larger ones. > > By also putting the time in there you can do the merge sort iterator, > Linus was right that everybody wants this anyway. > > As for delta encoding the time, we could make the tick log the absolute > time packet, that's at least 100Hz and it already has to compute the > full gtod thing anyway. > > I don't much like Linus' idea of bringing type information back into the > primitive header (sorry Linus ;-)). I'd much rather keep that > abstraction in the next layer.
There is part of the type stuff that belongs in the lower layer, it seems - the padding events for the up-to-end-of-page buffering, and the timestamp extensions. It seems wrong to split those across two layers.
But perhaps we can keep a couple of bits for this, and three of the bits to represent the length of the data payload (maybe in 4 byte multiples rather than bytes?) That'd let up to 28 bytes as a payload in a short event.
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