Re: [dpdk-dev] [PATCH v1] examples/vhost: fix ioat dependency issue

["Jiang, Cheng1" <cheng1.jiang@intel.com>]

Hi,

> -----Original Message-----
> From: David Marchand <david.marchand@redhat.com>
> Sent: Wednesday, November 11, 2020 10:36 PM
> To: Jiang, Cheng1 <cheng1.jiang@intel.com>
> Cc: Maxime Coquelin <maxime.coquelin@redhat.com>; Xia, Chenbo
> <chenbo.xia@intel.com>; dev <dev@dpdk.org>; Fu, Patrick
> <patrick.fu@intel.com>; Yang, YvonneX <yvonnex.yang@intel.com>; Hu,
> Jiayu <jiayu.hu@intel.com>; Thomas Monjalon <thomas@monjalon.net>;
> Yigit, Ferruh <ferruh.yigit@intel.com>
> Subject: Re: [PATCH v1] examples/vhost: fix ioat dependency issue
> 
> On Wed, Nov 11, 2020 at 12:29 PM Cheng Jiang <Cheng1.jiang@intel.com>
> wrote:
> >
> > Fix vhost-switch compiling issue when ioat dependency is missing.
> > Change 'RTE_x86' check into 'RTE_RAW_IOAT' check in meson build file
> > and update Makefile.
> 
> Still failing for me.
> 98b4c65506 - (HEAD) examples/vhost: fix ioat dependency issue (28
> seconds ago) <Cheng Jiang>
> a8adac0bc0 - (origin/main) doc: add instructions for building 32-bit
> DPDK (5 days ago) <Bruce Richardson>
> 
> Please try the reproducer I gave:
> 
> rm -f build/vhost-switch build/vhost-switch-static build/vhost-switch-shared
> test -d build && rmdir -p build || true
> cc -O3 -I/home/dmarchan/dpdk/installdir/usr/local/include -include
> rte_config.h -march=native -I/usr/usr/include
> -DALLOW_EXPERIMENTAL_API main.c virtio_net.c -o
> build/vhost-switch-shared -pthread -Wl,--as-needed
> -L/home/dmarchan/dpdk/installdir/usr/local/lib64 -lrte_node
> -lrte_graph -lrte_bpf -lrte_flow_classify -lrte_pipeline -lrte_table
> -lrte_port -lrte_fib -lrte_ipsec -lrte_vhost -lrte_stack
> -lrte_security -lrte_sched -lrte_reorder -lrte_rib -lrte_regexdev
> -lrte_rawdev -lrte_pdump -lrte_power -lrte_member -lrte_lpm
> -lrte_latencystats -lrte_kni -lrte_jobstats -lrte_ip_frag -lrte_gso
> -lrte_gro -lrte_eventdev -lrte_efd -lrte_distributor -lrte_cryptodev
> -lrte_compressdev -lrte_cfgfile -lrte_bitratestats -lrte_bbdev
> -lrte_acl -lrte_timer -lrte_hash -lrte_metrics -lrte_cmdline -lrte_pci
> -lrte_ethdev -lrte_meter -lrte_net -lrte_mbuf -lrte_mempool -lrte_rcu
> -lrte_ring -lrte_eal -lrte_telemetry -lrte_kvargs -lbsd
> /usr/bin/ld: /tmp/ccqE1W9S.o: in function `new_device':
> main.c:(.text+0x173): undefined reference to `ioat_transfer_data_cb'
> /usr/bin/ld: main.c:(.text+0x178): undefined reference to
> `ioat_check_completed_copies_cb'
> /usr/bin/ld: /tmp/ccqE1W9S.o: in function `main':
> main.c:(.text.startup+0x25e): undefined reference to `open_ioat'
> collect2: error: ld returned 1 exit status
> make: *** [Makefile:39: build/vhost-switch-shared] Error 1
> 
> 
> There are at least two problems:
> - the code in main.c unconditionally expects the ioat stuff to be
> available (this is why the link fails above),
> - the Makefile unconditionally compiles ioat.c, which you fixed with this patch,
> 
> There is a potential additional problem:
> I would expect a need for linking against the rte_raw_ioat driver, but
> we are "lucky" that all that is used in this example are inlines.
> So I guess it works without adding anything to LDFLAGS_SHARED.
> 
> 
> >
> > Signed-off-by: Cheng Jiang <Cheng1.jiang@intel.com>
> > ---
> >  examples/vhost/Makefile    | 5 +++++
> >  examples/vhost/ioat.h      | 2 +-
> >  examples/vhost/meson.build | 2 +-
> >  3 files changed, 7 insertions(+), 2 deletions(-)
> >
> > diff --git a/examples/vhost/Makefile b/examples/vhost/Makefile
> > index cec59d0e0f..505e443217 100644
> > --- a/examples/vhost/Makefile
> > +++ b/examples/vhost/Makefile
> > @@ -5,7 +5,12 @@
> >  APP = vhost-switch
> >
> >  # all source are stored in SRCS-y
> > +IOAT_PATH = $(shell pkg-config --cflags-only-I libdpdk | sed -e
> "s/^..//")/rte_ioat_rawdev.h
> > +ifeq ($(IOAT_PATH), $(wildcard $(IOAT_PATH)))
> > +SRCS-y := main.c virtio_net.c ioat.c
> > +else
> >  SRCS-y := main.c virtio_net.c
> > +endif
> 
> I'd rather rely on the driver define since the C code relies on it:
> Something like:
> 
>  PC_FILE := $(shell $(PKGCONF) --path libdpdk 2>/dev/null)
>  CFLAGS += -O3 $(shell $(PKGCONF) --cflags libdpdk)
>  LDFLAGS_SHARED = $(shell $(PKGCONF) --libs libdpdk)
>  LDFLAGS_STATIC = $(shell $(PKGCONF) --static --libs libdpdk)
> +
> +HAS_RAW_IOAT=$(shell echo RTE_RAW_IOAT | $(CPP) $(CFLAGS) -P - | tail
> -1)
> +ifeq ($(HAS_RAW_IOAT), 1)
> +SRCS-y += ioat.c
> +endif
> 

Sure, I will fix it in the next version, thanks a lot.

> 
> >
> >  # Build using pkg-config variables if possible
> >  ifneq ($(shell pkg-config --exists libdpdk && echo 0),0)
> > diff --git a/examples/vhost/ioat.h b/examples/vhost/ioat.h
> > index 9664fcc3ac..d6d0f7c18a 100644
> > --- a/examples/vhost/ioat.h
> > +++ b/examples/vhost/ioat.h
> > @@ -24,7 +24,7 @@ struct dma_for_vhost {
> >         uint16_t nr;
> >  };
> >
> > -#ifdef RTE_ARCH_X86
> > +#ifdef RTE_RAW_IOAT
> >  int open_ioat(const char *value);
> 
> main.c should check for RTE_RAW_IOAT before including ioat.h.
> And then in this header, you can remove this stub too.
> 

As for this one, ioat.h don't have dependency on IOAT driver, it is needed by the example regardless of whether the raw/ioat driver exists. And I added more RTE_RAW_IOAT check in ioat.h. Now it can be compiled.

Thanks,
Cheng

> 
> >  #else
> >  static int open_ioat(const char *value __rte_unused)
> 
> 
> --
> David Marchand