On Wed, May 25, 2016 at 07:39:30PM +0200, Thomas Monjalon wrote:
> 2016-05-25 13:22, Neil Horman:
> > On Wed, May 25, 2016 at 03:21:19PM +0200, Thomas Monjalon wrote:
> > > 2016-05-24 15:41, Neil Horman:
> > > > --- a/GNUmakefile
> > > > +++ b/GNUmakefile
> > > > -ROOTDIRS-y := lib drivers app
> > > > +ROOTDIRS-y := buildtools lib drivers app
> > >
> > > Why a new directory?
> > > It is not a script nor an end-user tool, I guess.
> > Dependencies. This tool has to be built prior to the rest of the dpdk, but app
> > already relies on dpdk libraries to be built, so you get circular dependencies.
> > I could have put it in scripts I guess, but its not a script. Its own directory
> > seemed to make the most sense, given those two points
>
> OK
>
> > > > +include $(RTE_SDK)/mk/rte.buildtools.mk
> > >
> > > Why a new Makefile? Can you use rte.hostapp.mk?
> > >
> > I don't know, maybe. Nothing else currently uses rte.hostapp.mk, so I missed
> > its existance. I make the argument that, that being the case, we should stick
> > with the Makefile I just tested with, and remove the rte.hostapp.mk file
>
> No, rte.hostapp.mk has been used and tested in the history of the project.
> Please try it.
>
It works, but its really ugly (as it means that the buildtools directory gets
install to the hostapp directory under the build). I could move that of course,
but at this point, you are asking me to remove a working makefile to replace it
with another makefile that, by all rights should have been removed as part of
commit efa2084a840fb83fd9be83adca57e5f23d3fa9fe:
Author: Thomas Monjalon <thomas.monjalon at 6wind.com>
Date: Tue Mar 10 17:55:25 2015 +0100
scripts: remove useless build tools
test-framework.sh is an old script to check building of some dependencies.
testhost is an old app used to check HOSTCC.
Let's clean the scripts directory.
Here you removed the only user of rte.hostapp.mk, but neglected to remove
hostapp.mk itself. I really fail to see why making me rework my current
makefile setup, that matches the purpose of the tool is a superior solution to
just getting rid of the unused makefile thats there right now.
> > > > +++ b/buildtools/pmdinfogen/pmdinfogen.c
> > > [...]
> > > > + /*
> > > > + * If this returns NULL, then this is a PMD_VDEV, because
> > > > + * it has no pci table reference
> > > > + */
> > >
> > > We can imagine physical PMD not using PCI.
> > > I think this comment should be removed.
> > We can, but currently its a true statement. we have two types of PMDs, a PDEV
> > and a VDEV, the former is a pci device, and the latter is a virtual device, so
> > you can imply the PDEV type from the presence of pci entries, and VDEV from the
> > alternative. If we were to do something, I would recommend adding a macro to
> > explicitly ennumerate each pmds type. I would prefer to wait until that was a
> > need however, as it can be done invisibly to the user.
>
> We are removing the PMD types in the EAL rework.
> So this comment will be outdated. Better to remove now.
>
Then, I'm just not going to enumerate the type of driver at all, I'll remove
that attribute entirely. But I really don't like to write code for things that
are 'predictive'.
> > > [...]
> > > > + fprintf(ofd,"\\\"type\\\" : \\\"%s\\\", ", drv->pci_tbl ? "PMD_PDEV" : "PMD_VDEV");
> > >
> > > Please forget the naming PDEV/VDEV.
> > >
> > I don't know what you mean here, you would rather they be named PCI and Virtual,
> > or something else?
>
> Yes please.
>
No, If you're removing the types, and you're sure of that, I'm just going to
remove the description entirely. If you're unsure about exactly whats going to
happen, we should reflect the state of the build now, and make the appropriate
change when it lands.
> > > [...]
> > > > + if (info.drivers) {
> > > > + output_pmd_info_string(&info, argv[2]);
> > > > + rc = 0;
> > > > + } else {
> > > > + fprintf(stderr, "Hmm, Appears to be a driver but no drivers registered\n");
> > >
> > > Why it appears to be a driver?
> > > What means "no drivers registered" exactly?
> > >
> > It means that the tool has identified this file as a driver based on some
> > criteria (in this case the source code contained a use of the
> > PMD_REGISTER_DRIVER macro, but for whatever reason, when this tool scanned it,
> > it never located the pmd_driver_name<n> symbol. It should never happen, and
> > serves as a indicator to the developer that they need to investigate either the
> > construction of the driver or the use of this tool.
>
> OK
>
> > > > +++ b/buildtools/pmdinfogen/pmdinfogen.h
> > > [...]
> > > > +#define Elf_Ehdr Elf64_Ehdr
> > > > +#define Elf_Shdr Elf64_Shdr
> > > > +#define Elf_Sym Elf64_Sym
> > > > +#define Elf_Addr Elf64_Addr
> > > > +#define Elf_Sword Elf64_Sxword
> > > > +#define Elf_Section Elf64_Half
> > > > +#define ELF_ST_BIND ELF64_ST_BIND
> > > > +#define ELF_ST_TYPE ELF64_ST_TYPE
> > > > +
> > > > +#define Elf_Rel Elf64_Rel
> > > > +#define Elf_Rela Elf64_Rela
> > > > +#define ELF_R_SYM ELF64_R_SYM
> > > > +#define ELF_R_TYPE ELF64_R_TYPE
> > >
> > > Why these defines are needed?
> > >
> > Because I borrowed the code from modpost.c, which allows for both ELF32 and
> > ELF64 compilation. I wanted to keep it in place should DPDK ever target
> > different sized architectures.
>
> Maybe a comment is needed.
> Is ELF32 used on 32-bit archs like i686 or ARMv7?
It depends on exactly how its built, but that would be a common use, yes.
>
> > > > +struct rte_pci_id {
> > > > + uint16_t vendor_id; /**< Vendor ID or PCI_ANY_ID. */
> > > > + uint16_t device_id; /**< Device ID or PCI_ANY_ID. */
> > > > + uint16_t subsystem_vendor_id; /**< Subsystem vendor ID or PCI_ANY_ID. */
> > > > + uint16_t subsystem_device_id; /**< Subsystem device ID or PCI_ANY_ID. */
> > > > +};
> > > [...]
> > > > +struct pmd_driver {
> > > > + Elf_Sym *name_sym;
> > > > + const char *name;
> > > > + struct rte_pci_id *pci_tbl;
> > > > + struct pmd_driver *next;
> > > > +
> > > > + const char* opt_vals[PMD_OPT_MAX];
> > > > +};
> > >
> > > Are you duplicating some structures from EAL?
> > > It will be out of sync easily.
> > >
> > Only the rte_pci_id, which hasn't changed since the initial public release of
> > the DPDK. We can clean this up later if you like, but I'm really not too
> > worried about it.
>
> I would prefer an include if possible.
> rte_pci_id is changing in 16.07 ;)
>
So, we've had this discussion before :). Its really not fair to ask anyone to
write code based on predictive changes. If theres some patch out there thats
planning on making a change, we can't be expected to write with it in mind. If
you want people to use it, then get it merged. I understand thats not really
the issue here, and I'm making the change because you're right, we should avoid
duplicating the structures if we can, but please understand that its impossible
to write for change thats predicted to come at a later date.
> > > > +struct elf_info {
> > > > + unsigned long size;
> > > > + Elf_Ehdr *hdr;
> > > > + Elf_Shdr *sechdrs;
> > > > + Elf_Sym *symtab_start;
> > > > + Elf_Sym *symtab_stop;
> > > > + Elf_Section export_sec;
> > > > + Elf_Section export_unused_sec;
> > > > + Elf_Section export_gpl_sec;
> > > > + Elf_Section export_unused_gpl_sec;
> > > > + Elf_Section export_gpl_future_sec;
> > > > + char *strtab;
> > > > + char *modinfo;
> > > > + unsigned int modinfo_len;
> > >
> > > Why these fields?
> > >
> > Because thats how you parse an ELF file and look up the information you need to
> > extract the data this tool then exports. I don't mean to sound short, but your
> > question doesn't really make any sense. The members of this structure are
> > needed to extract the info from object files to build the export strings that
> > pmdinfo.py needs later.
>
> Sorry, I haven't parse the whole code but some fields are unused.
> And modinfo looks wrong.
>
Yup, your right, modifo did get orphaned when I was doing previous cleanup, and
can be removed.
> > > > +++ b/mk/rte.buildtools.mk
> > >
> > > This file must be removed I think.
> > > We are going to be sick after digesting so much makefiles ;)
> > >
> > See above, given that I just tested this, and rte.hostapp.mk isn't used, I'd
> > recommend deleting the latter, rather than deleting this one and moving to the
> > old one.
>
> See above, I do not agree :)
>
Then we're not going to agree about this :). I'll re-iterate my stance. Moving to
use rte.hotapp.mk, causes alot more work for me, makes the use of the tool
somewhat uglier, and by all rights shouldn't be there at all, due to your
previously mentioned commit. It just makes more sense to use the buildtools
makefile and remove the vesitgial rte.hostapp.mk makefile.
Neil
>