[dpdk-dev] Question about log levels and rte_panic

[dpdk-dev] Question about log levels and rte_panic

[Wiles, Keith]

I have some code I have been debugging that does a rte_panic() at some point. The problem is it just appeared to exit without printing the panic message. I tracked it down to rte_vlog() doing the following test.

 if ((level > rte_logs.level) || !(logtype & rte_logs.type))
      return 0;
 
The reason it appears to just exit to the shell is I was setting —log-level 0 on the command line, which means no CRIT, EMERG or ALERTs panic messages are printed. If I set the log-level 3 then I am able to see these ‘critical’ panic messages, is this the expected behavior?

I would expect EMERG, ALERT and CRIT messages to be printed regardless of the log-level value, but I guess it just means log-level 3 is the lowest level unless you really do not want these messages printed.


Regards,
Keith

Re: [dpdk-dev] Question about log levels and rte_panic

[Matthew Hall]

> On Feb 13, 2016, at 9:43 AM, Wiles, Keith <keith.wiles@intel.com> wrote:
> 
> I would expect EMERG, ALERT and CRIT messages to be printed regardless of the log-level value

I wouldn't expect that based on the traditional custom of syslog daemons. If you specify a filter configuration, such as setlogmask or some custom logic in the syslog daemon itself, the logging system should respect it. Even if it might not make sense to a given individual.

That said, rte_panic should be making sure the messages it generates always get logged, regardless of the logging system settings, because it is hijacking control of your process which is a very hostile act. This special exemption should only happen for things that are truly fatal. Not anything else.

Matthew.

Re: [dpdk-dev] Question about log levels and rte_panic

[Stephen Hemminger]

On Sat, 13 Feb 2016 17:43:38 +0000
"Wiles, Keith" <keith.wiles@intel.com> wrote:

> The reason it appears to just exit to the shell is I was setting —log-level 0 on the command line, which means no CRIT, EMERG or ALERTs panic messages are printed. If I set the log-level 3 then I am able to see these ‘critical’ panic messages, is this the expected behavior?

You got what you asked for. I don't see a problem with that...