Messages in this thread | | | Date | Wed, 27 May 2015 23:09:58 -0700 | From | Alexei Starovoitov <> | Subject | Re: [RFC PATCH v4 10/29] bpf tools: Collect map definitions from 'maps' section |
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On Thu, May 28, 2015 at 11:09:50AM +0800, Wangnan (F) wrote: > > However this breaks a law in current design that opening phase doesn't > talk to kernel with sys_bpf() at all. All related staff is done in loading > phase. This principle ensures that in every systems, no matter it support > sys_bpf() or not, can read eBPF object without failure.
I see, so you want 'parse elf' and 'create maps + load programs' to be separate phases? Fair enough. Then please add a call to release the information collected from elf after program loading is done. relocations and other things are not needed at that point.
> Moreover, we are planning to introduce hardware PMU to eBPF in the way like > maps, > to give eBPF programs the ability to access hardware PMU counter. I haven't
that's very interesting. Please share more info when you can :) If I understood it right, you want in-kernel bpf to do aggregation and filtering of pmu counters ? And computing a number of cache misses between two kprobe events? I can see how I can use that to measure not only time taken by syscall, but number of cache misses occurred due to syscall. Sounds very useful!
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