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Syncing latest usdt.h change [1]. Now that we have no5 optimization support in kernel, let's emit nop,nop5 for usdt probe. We leave it up to the library to use desirable nop instruction. [1] libbpf/usdt@c9865d1 Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding uprobe syscall feature detection that will be used in following changes. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding support to detect nop,nop5 instructions combo for usdt probe by checking on probe's following nop5 instruction. When the nop,nop5 combo is detected together with uprobe syscall, we can place the probe on top of nop5 and get it optimized. [1] https://github.com/libbpf/usdt Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding test that attaches bpf program on usdt probe in 2 scenarios; - attach program on top of usdt_1, which is single nop instruction, so the probe stays on nop instruction and is not optimized. - attach program on top of usdt_2 which is probe defined on top of nop,nop5 combo, so the probe is placed on top of nop5 and is optimized. Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Adding usdt trigger bench for usdt: trig-usdt_nop - usdt on top of nop1 instruction trig-usdt_nop_combo - usdt on top of nop1/nop5 combo Adding it to benchs/run_bench_uprobes.sh script. Example run on x86_64 kernel with uprobe syscall: # ./benchs/run_bench_uprobes.sh usermode-count : 152.507 ± 0.098M/s syscall-count : 14.309 ± 0.093M/s uprobe-nop : 3.190 ± 0.012M/s uprobe-push : 3.057 ± 0.004M/s uprobe-ret : 1.095 ± 0.009M/s uprobe-nop5 : 7.305 ± 0.034M/s uretprobe-nop : 2.175 ± 0.005M/s uretprobe-push : 2.109 ± 0.003M/s uretprobe-ret : 0.945 ± 0.002M/s uretprobe-nop5 : 3.530 ± 0.006M/s usdt_nop : 3.235 ± 0.008M/s <-- added usdt_nop_combo : 7.511 ± 0.045M/s <-- added Signed-off-by: Jiri Olsa <jolsa@kernel.org>
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