> Subject: Re: [PATCH] net/mana: use RTE_LOG_DP for logs on datapath > > On 3/3/2023 2:16 AM, Long Li wrote: > >> Subject: Re: [PATCH] net/mana: use RTE_LOG_DP for logs on datapath > >> > >> On Thu, 23 Feb 2023 10:09:17 -0800 > >> Stephen Hemminger <step...@networkplumber.org> wrote: > >> > >>> On Thu, 23 Feb 2023 14:07:25 +0000 > >>> Ferruh Yigit <ferruh.yi...@amd.com> wrote: > >>> > >>>> Overall I am not sure if anyone is interested in driver datapath > >>>> logs other than driver developers themselves. > >>>> > >>>> For datapath logging I think there are two concerns, > >>>> 1) It should not eat *any* cycles unless explicitly enabled > >>>> 2) Capability of enable/disable them because of massive amount of > >>>> log it can generate > >>>> > >>>> > >>>> Currently there are two existing approaches for driver datapath logging: > >>>> i) Controlled by 'RTE_ETHDEV_DEBUG_RX/TX' compile time flag, > >>>> when enabled 'rte_log()' is used with Rx/Tx specific log type. > >>>> ii) 'RTE_LOG_DP' ', compile time control per logtype via > >>>> 'RTE_LOG_DP_LEVEL', > >>>> when enabled 'rte_log()' is used with PMD logtype. > >>>> > >>>> > >>>> In (ii), need to re-compile code when you need to increase the log > >>>> verbosity, and it leaks to production code as mentioned above. > >>>> > >>>> For (i), developer compiles once enabling debug, later can fine > >>>> grain log level dynamically. This is more DPDK developer focused > approach. > >>>> > >>>> > >>>> [1] > >>>> According above, what do you think to retire 'RTE_LOG_DP', (at > >>>> least within ethdev datapath), and chose (i) as preferred datapath > logging? > >>> > >>> I agree, the current tx/rx logging is a mess. > >>> Each driver is different, each driver has to have something to > >>> enable it; and it really isn't useful beyond the driver developer. > >>> > >>> Using tracing seems like a much better option. Could we agree on a > >>> common set of trace points for drivers and fix all drivers to use > >>> the same > >> thing. > >>> Probably will cause some upset among driver developers: > >>> "where did my nice printf's go, now I have to learn tracing" > >>> but DPDK has a good facility here, lets use it. > >>> > >>> My proposal would be: > >>> - agree on common set of trace points > >>> - apply to all drivers > >>> - remove RTE_LOG_DP() > >>> - remove per driver RX/TX options > >>> - side effect, more uses of RTE_LOGTYPE_PMD go away. > >> > >> Here is an example of using tracepoints instead. > >> Compile tested for example only. > >> > >> Note: using tracepoints it is possible to keep some of the > >> tracepoints even if fastpath is not enabled. Things like running out > >> of Tx or Mbuf is not something that is perf critical; but would be good for > application to see. > > > > Thank you for the example. > > > > I sent another patch converting data path logs (mana) to trace points. > > > > Hi Long, > > Thanks for the effort, you were quick on this while discussion is going on. > > Although tracepoint is a good feature, I am not sure if it can fully replace > the > logging. > I think usage is slightly different, trace is missing custom human readable > message, which can be very helpful for end user. > > And overall, it is a high level decision to switch logging to trace, it is > inconsistent to switch only single driver, perhaps techboard (cc'ed) can > discuss > this. > > Until such consensus reached, I think driver should continue with logging. > > > > And for the logging, I suggest option (i) above, I was hoping more comments > but since it is missing I hope this can be discussed in techboard for a > conclusion.
Hi Ferruh, Are you suggesting that MANA should use 'RTE_ETHDEV_DEBUG_RX/TX'? I'm happy to implement the logging in this way. Long
