On Fri, 2013-07-26 at 15:06 +0200, Johannes Berg wrote: > On Fri, 2013-07-26 at 08:28 -0400, Steven Rostedt wrote: > Ah, yes, that'd work. I was considering putting it into the trace event > handling itself so I don't have to allocate those buffers and put the > handling into every tracepoint, but I don't know how that'd work with > interrupts coming in. If you create helper functions, it shouldn't be too hard. > > If we assume that interrupts coming in in the middle of a tracepoint > should be rare, we could do something like > > * allocate max buffer in on the tracing ringbuffer page > * write data into it > * if no interrupt came in, reduce reservation > > but I'm not sure how to implement step 3 :) > It's possible to reduce the ring buffer, it's just not implemented. I'm not sure I want to do that either. Interrupts coming in is not so rare as it can be any interrupt being traced. This means your tracepoints will likely waste a lot of buffer space if you are tracing interrupts as well. That said, I can probably implement a reduce feature of the ring buffer if needed. -- Steve -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
