Hi Mykyta, On 2024/9/19 04:39, Mykyta Yatsenko wrote:
From: Mykyta Yatsenko <yatsenko@xxxxxxxx> Production BPF programs are increasing in number of instructions and states to the point, where optimising verification process for them is necessary to avoid running into instruction limit. Authors of those BPF programs need to analyze verifier output, for example, collecting the most frequent source code lines to understand which part of the program has the biggest verification cost. This patch introduces `--top-src-lines` flag in veristat. `--top-src-lines=N` makes veristat output N the most popular sorce code lines, parsed from verification log. An example: ``` $ sudo ./veristat --log-size=1000000000 --top-src-lines=4 pyperf600.bpf.o Processing 'pyperf600.bpf.o'... Top source lines (on_event): 4697: (pyperf.h:0) 2334: (pyperf.h:326) event->stack[i] = *symbol_id; 2334: (pyperf.h:118) pidData->offsets.String_data); 1176: (pyperf.h:92) bpf_probe_read_user(&frame->f_back, ... ```
I think this is useful and wonder how can I use it. In particular, is it possible to know the corresponding instruction number contributed by the source lines?
Assume a prog is rejected due to instruction limit. I can optimize the prog with `--top-src-lines`, but have to check the result with another "load" to see the total instruction number (because I don't know how many instructions reduced with the optimized src lines).
Am I right? or is there any better method? Thanks. -- Philo
