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Date: Fri, 22 Dec 2017 14:45:41 +0100
From: Olivier MATZ <olivier.matz@6wind.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: Stephen Hemminger <stephen@networkplumber.org>, dev@dpdk.org
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Subject: Re: [dpdk-dev] [PATCH 01/11] avp: implement dynamic logging
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On Thu, Dec 21, 2017 at 10:02:14AM -0800, Ferruh Yigit wrote:
> On 12/20/2017 10:58 AM, Stephen Hemminger wrote:
> >> [1] something like:
> >>  #define INIT_LOG_VAR_NAME(pmd, type)   logtype_ ## pmd ## _ ## type
> >>  #define INIT_LOG_FUNC_NAME(pmd, type)  log_ ## pmd ## _ ## type
> >>
> >>  #define PMD_INIT_LOG(pmd, type, level)                                \
> >>         int INIT_LOG_VAR_NAME(pmd, type);                       \
> >>         RTE_INIT(INIT_LOG_FUNC_NAME(pmd, type));                \
> >>         static void INIT_LOG_FUNC_NAME(pmd, type)(void)                 \
> >>         {                                                       \
> >>                 INIT_LOG_VAR_NAME(pmd, type) = rte_log_register("pmd."
> >> RTE_STR(pmd) "." RTE_STR(type)); \
> >>                 if (INIT_LOG_VAR_NAME(pmd, type) > 0)           \
> >>                         rte_log_set_level(INIT_LOG_VAR_NAME(pmd, type),
> >> RTE_LOG_##level); \
> >>         }
> > 
> > That macro is a little complex.  Also, for better or worse, the current
> > logging is done on a per driver basis. If we want to do something fancier
> > it should be in common EAL core.
> 
> Of course, my intention was putting it into rte_log.h so updates in each driver
> will be minimal. But this can be done better to cover library updates as well.

It's a good idea.

Below is another proposition (untested) that panics if
rte_log_register() fails, and that defines a static variable with a
predefined name.

 #define RTE_LOG_TYPE_REGISTER(name, level)                              \
         static int name##_log_type;                                     \
         __attribute__((constructor, used))                              \
         static void rte_log_register_##name(void)                       \
         {                                                               \
                 name##_log_type = rte_log_register(#name);              \
                 RTE_VERIFY(name##_log_type >= 0);                       \
                 rte_log_set_level(name##_log_type, level);              \
         }