> -----Original Message----- > From: Ferruh Yigit <ferruh.yi...@amd.com> > Sent: Friday, March 3, 2023 5:15 PM > To: Long Li <lon...@microsoft.com>; Stephen Hemminger > <step...@networkplumber.org> > Cc: lon...@linuxonhyperv.com; Thomas Monjalon <tho...@monjalon.net>; > Andrew Rybchenko <andrew.rybche...@oktetlabs.ru>; Jerin Jacob > Kollanukkaran <jer...@marvell.com>; David Marchand > <david.march...@redhat.com>; dev@dpdk.org; Ajay Sharma > <sharmaa...@microsoft.com>; sta...@dpdk.org; Luca Boccassi > <bl...@debian.org>; Qi Z Zhang <qi.z.zh...@intel.com>; Ajit Khaparde > <ajit.khapa...@broadcom.com>; Bruce Richardson > <bruce.richard...@intel.com>; Konstantin Ananyev > <konstantin.v.anan...@yandex.ru>; Olivier Matz <olivier.m...@6wind.com>; > Honnappa Nagarahalli <honnappa.nagaraha...@arm.com>; techbo...@dpdk.org > Subject: Re: [PATCH] net/mana: use RTE_LOG_DP for logs on datapath > > On 3/3/2023 7:04 PM, Long Li wrote: > >> 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. > > > > Yes, that looks to me better balance for compile time / runtime config for > drive > developers. > > But it prevents product code / end user to get data path logs, although I > believe > this is OK I am not sure how useful datapath logs in production code, that is > why I > am looking for more comment for a decision. > > Let's wait for next techboard meeting, in case this is discussed there, before > making new implementation.
HI Ferruh, Have we reached a decision on how to implement data path logs? Thanks, Long
