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2016-04-14bpf, samples: don't zero data when not neededDaniel Borkmann1-4/+6
Remove the zero initialization in the sample programs where appropriate. Note that this is an optimization which is now possible, old programs still doing the zero initialization are just fine as well. Also, make sure we don't have padding issues when we don't memset() the entire struct anymore. Signed-off-by: Daniel Borkmann <daniel@iogearbox.net> Acked-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-04-07samples/bpf: tracepoint exampleAlexei Starovoitov1-4/+22
modify offwaketime to work with sched/sched_switch tracepoint instead of kprobe into finish_task_switch Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>
2016-02-20samples/bpf: offwaketime exampleAlexei Starovoitov1-0/+131
This is simplified version of Brendan Gregg's offwaketime: This program shows kernel stack traces and task names that were blocked and "off-CPU", along with the stack traces and task names for the threads that woke them, and the total elapsed time from when they blocked to when they were woken up. The combined stacks, task names, and total time is summarized in kernel context for efficiency. Example: $ sudo ./offwaketime | flamegraph.pl > demo.svg Open demo.svg in the browser as FlameGraph visualization. Signed-off-by: Alexei Starovoitov <ast@kernel.org> Signed-off-by: David S. Miller <davem@davemloft.net>