On 2019-01-11 10:55 a.m., Arnaldo Carvalho de Melo wrote:
Hi Peter,bpf_perf_event_open() already returns a value, but if perf_event_output's output_begin (mostly perf_output_begin) fails, the only way to know about that is looking before/after the rb->lost, right? For ring buffer users that is ok, we'll get a PERF_RECORD_LOST, etc, but for BPF programs it would be convenient to get that -ENOSPC and do some fallback, whatever makes sense, like in my augmented_syscalls stuff for 'perf trace', i.e. don't augment it (i.e. push stuff at the end of the normal payload), just don't filter the raw_syscalls:sys_enter, 'perf trace' will get the enter syscall enter event without the pointer dereference at the end, etc, warn the user but don't lose a syscall in the strace-like output. What do you think? Am I missing something? Probably ;-) Ah, its just test built.
Works as advertised ;-> Tested-by: Jamal Hadi Salim <[email protected]> cheers, jamal
