Messages in this thread | | | Date | Thu, 5 Dec 2013 14:36:58 -0800 | Subject | Re: [RFC PATCH tip 0/5] tracing filters with BPF | From | Alexei Starovoitov <> |
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On Thu, Dec 5, 2013 at 5:46 AM, Steven Rostedt <rostedt@goodmis.org> wrote: > > I know that it would be great to have the bpf filter run before > recording of the tracepoint, but as that becomes quite awkward for a > user interface, because it requires intimate knowledge of the kernel > source, this speed up on the filter itself may be worth while to have > it happen after the recording of the buffer. When it happens after the > record, then the bpf has direct access to the event entry and its > fields as described by the trace event format files.
I don't understand that 'awkward' part yet. What do you mean by 'knowledge of the kernel'? By accessing pt_regs structure? Something else ? Can we try fixing the interface first before compromising on performance?
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