Messages in this thread | | | Date | Wed, 13 Jul 2016 18:53:27 +0200 | From | Daniel Borkmann <> | Subject | Re: [PATCH net-next 1/3] perf, events: add non-linear data support for raw records |
| |
On 07/13/2016 06:40 PM, Peter Zijlstra wrote: > On Wed, Jul 13, 2016 at 04:08:55PM +0200, Daniel Borkmann wrote: >> On 07/13/2016 03:42 PM, Peter Zijlstra wrote: >>> >>> Ok so the nonlinear thing was it doing _two_ copies, one the regular >>> __output_copy() on raw->data and second the optional fragment thingy >>> using __output_custom(). >>> >>> Would something like this work instead? >>> >>> It does the nonlinear thing and the custom copy function thing but >>> allows more than 2 fragments and allows each fragment to have a custom >>> copy. >>> >>> It doesn't look obviously more expensive; it has the one ->copy branch >>> extra, but then it doesn't recompute the sizes. >> >> Yes, that would work as well on a quick glance with diff just a bit >> bigger, but more generic this way. Do you want me to adapt this into >> the first patch? > > Please. > >> One question below: >> > >>> - u64 zero = 0; > >>> - if (real_size - raw_size) >>> - __output_copy(handle, &zero, real_size - raw_size); > >> We still need the zero padding here from above with the computed >> raw->size, right? > > Ah, yes, we need some __output*() in order to advance the handle offset. > We don't _need_ to copy the 0s, but I doubt __output_skip() is much > cheaper for these 1-3 bytes worth of data; we've already touched that > line anyway.
Okay, thanks for your input! I'll respin then.
| |