Hi Ali, > -----Original Message----- > From: Ali Alnubani <[email protected]> > Sent: Wednesday, April 21, 2021 3:25 PM > To: Dumitrescu, Cristian <[email protected]> > Cc: [email protected]; NBU-Contact-Thomas Monjalon > <[email protected]>; Aaron Conole <[email protected]> > Subject: RE: [dpdk-dev] [PATCH 2/2] pipeline: autodetect endianness of > action args > > Hi Cristian, > > > -----Original Message----- > > From: Dumitrescu, Cristian <[email protected]> > > Sent: Wednesday, April 21, 2021 4:58 PM > > To: Ali Alnubani <[email protected]>; NBU-Contact-Thomas Monjalon > > <[email protected]>; Aaron Conole <[email protected]> > > Cc: [email protected] > > Subject: RE: [dpdk-dev] [PATCH 2/2] pipeline: autodetect endianness of > > action args > > > > > > > > > -----Original Message----- > > > From: Ali Alnubani <[email protected]> > > > Sent: Wednesday, April 21, 2021 8:50 AM > > > To: NBU-Contact-Thomas Monjalon <[email protected]>; > Dumitrescu, > > > Cristian <[email protected]>; Aaron Conole > > > <[email protected]> > > > Cc: [email protected] > > > Subject: RE: [dpdk-dev] [PATCH 2/2] pipeline: autodetect endianness of > > > action args > > > > > > Hi, > > > > > > > -----Original Message----- > > > > From: dev <[email protected]> On Behalf Of Thomas Monjalon > > > > Sent: Tuesday, April 20, 2021 10:58 PM > > > > To: Cristian Dumitrescu <[email protected]> > > > > Cc: [email protected] > > > > Subject: Re: [dpdk-dev] [PATCH 2/2] pipeline: autodetect endianness > of > > > > action args > > > > > > > > 12/04/2021 01:23, Cristian Dumitrescu: > > > > > Each table entry is made up of match fields and action data, with the > > > > > latter made up of the action ID and the action arguments. The > approach > > > > > of having the user specify explicitly the endianness of the action > > > > > arguments is difficult to be picked up by P4 compilers, as the P4 > > > > > compiler is generally unaware about this aspect. > > > > > > > > > > This commit introduces the auto-detection of the endianness of the > > > > > action arguments by examining the endianness of the their > destination: > > > > > network byte order (NBO) when they get copied to headers and host > > > byte > > > > > order (HBO) when they get copied to packet meta-data or mailboxes. > > > > > > > > > > The endianness specification of each action argument as part of the > > > > > rule specification, e.g. H(...) and N(...) is removed from the rule > > > > > file and auto-detected based on their destination. The DMA > instruction > > > > > scope is made internal, so mov instructions need to be used. The > > > > > pattern of transferring complete headers from table entry action args > > > > > to headers is detected, and the associated set of mov instructions > > > > > plus header validate is internally detected and replaced with the > > > > > internal-only DMA instruction to preserve performance. > > > > > > > > > > Signed-off-by: Cristian Dumitrescu <[email protected]> > > > > > > > > Series applied, thanks > > > > > > > > > > > > > > I believe this patchset is causing the build failures in > > > https://bugs.dpdk.org/show_bug.cgi?id=683. > > > > > > Regards, > > > Ali > > > > Hi Ali, > > > > I checked this issue and here are my findings: > > > > 1. The compiler warnings are NOT caused by this patch, all of them are > > triggered by older code. > > Git-bisect pointed to this patch. The errors didn't reproduce without it.
This is strange, as code that your patch (as well as mine) "fixed" was not modified by this "pipeline: autodetect endianness ..." patch (easy to check). Likely this patch triggered some bad memories in the "mind" of the compiler, but TBH I don't think we need to debug it at this point :) > > > 2. Why were they not triggered before? Either this is the first time CentOS > 7 > > is run or the compiler has a mind of its own (my vote goes to the former). > > The check ci/iol-testing contains an image with gcc 4.8.5 (RHEL 7), and I see > now that it reproduced the errors in recent patches. See the failing build > check in https://lab.dpdk.org/results/dashboard/patchsets/16682/ (under > dpdk_meson_compile). > > > 3. These are all 100% fake issues that are probably triggered by the old GCC > > version from CentOS 7. > > > > I just sent a patch now (you are copied on it) with some harmless local > > variable initializations in the hope it will stop these warnings on CentOS > > 7. > As I > > don't have access to a CentOS 7 machine, can you please confirm whether > > the warnings are fixed? > > > > I submitted a patch and updated the status of the Bugzilla ticket a few hours > ago. See https://bugs.dpdk.org/show_bug.cgi?id=683#c4. > Cool, thank you for looking at this issue and doing the work to fix it. I did not see your patch in time, as for some reasons it landed in the bin folder as opposed to my usual DPDK folder. > > As the warnings are triggered selectively for just more occurrences of a > > common pattern as opposed to all occurrences, I am trying to fix all > > occurrences of this pattern in order to prevent the same warnings showing > > up again. > > > > I only initialized occurrences of dst_struct_id and src_struct_id to resolve > it > though, maybe rebase and update your patch if you think initializing the rest > is necessary? > There are a few others that might be triggered at some point, but difficult to have a full list now, maybe it is better to wait for now. > Thanks, > Ali Thanks, Cristian
