On Tue, 30 Apr 2019 08:31:53 -0700, Y Song wrote:

On Tue, Apr 30, 2019 at 2:34 AM Quentin Monnet
[off-list ref] wrote:

quoted

Hi Yonghong,

2019-04-29 16:32 UTC-0700 ~ Y Song [off-list ref]  

quoted

On Mon, Apr 29, 2019 at 2:53 AM Quentin Monnet
[off-list ref] wrote:  

quoted

libbpf has three levels of priority for output: warn, info, debug. By
default, debug output is not printed to stderr.

Add a new "--log-libbpf LOG_LEVEL" option to bpftool to provide more
flexibility on the log level for libbpf. LOG_LEVEL is a comma-separated
list of levels of log to print ("warn", "info", "debug"). The value
corresponding to the default behaviour would be "warn,info".  

Do you think option like "warn,debug" will be useful for bpftool users?
Maybe at bpftool level, we could allow user only to supply minimum level
for log output, e.g., "info" will output "warn,info"?  

I've been pondering this, too. Since we allow to combine all levels for
the verifier logs it feels a bit odd to be less flexible for libbpf. And
we could imagine a user who wants verifier logs (so libbpf "debug") but
prefers to limit libbpf output (so no "info")... Although I admit this
might be a bit far-fetched.

I can resend a version with the option taking only the minimal log
level, as you describe, if you think this is best.  

Thanks, I think providing a single minimum level for output probably
better.

I have a weak preference for what we have here, because it's similar to
the kernel bit opt in (log level, stats etc)..