From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Panu Matilainen <pmatilai@redhat.com>,
Christian Ehrhardt <christian.ehrhardt@canonical.com>
Cc: Thomas Monjalon <thomas.monjalon@6wind.com>, dev <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH] mk: fix underlinking issues of most librte libraries
Date: Fri, 27 May 2016 17:15:47 +0100 [thread overview]
Message-ID: <574872B3.6040702@intel.com> (raw)
In-Reply-To: <c65769c5-f392-8a51-42b9-2e1398e9d41a@redhat.com>
On 5/27/2016 6:59 AM, Panu Matilainen wrote:
> On 05/26/2016 04:13 PM, Ferruh Yigit wrote:
>> On 5/24/2016 11:11 AM, Christian Ehrhardt wrote:
>>> Hi Panu,
>>> I already agreed to Thomas on IRC but won't have time until next week.
>>> Thanks for making a patch that does that already - I'll give it a look and
>>> some test on my end next week then.
>>>
>>>
>>>
>>> Christian Ehrhardt
>>> Software Engineer, Ubuntu Server
>>> Canonical Ltd
>>>
>>> On Tue, May 24, 2016 at 11:56 AM, Panu Matilainen <pmatilai@redhat.com>
>>> wrote:
>>>
>>>> On 05/20/2016 08:08 PM, Thomas Monjalon wrote:
>>>>
>>>>> 2016-05-20 18:50, Christian Ehrhardt:
>>>>>
>>>>>> The individual libraries have various cross dependencies.
>>>>>> This is already refelcted in the DEPDIR dependency, but not yet in
>>>>>> proper DT_NEEDED flags in the .so's.
>>>>>> This adds the -l flags so that is properly stored in the .so's ELF
>>>>>> headers.
>>>>>>
>>>>>
>>>>> Why not filling LDLIBS by parsing DEPDIRS-y in rte.lib.mk?
>>>>>
>>>>>
>>>> A fair question :) The thought has passed my mind too, but I thought it'd
>>>> be too messy with differing library vs directory names and other
>>>> exceptions. But in reality manually maintained separate LDLIBS is only
>>>> going to get out of sync sooner or later, and turns out its not that bad
>>>> anyway:
>>>>
>>>> diff --git a/mk/rte.lib.mk b/mk/rte.lib.mk
>>>> index b420280..88b4e98 100644
>>>> --- a/mk/rte.lib.mk
>>>> +++ b/mk/rte.lib.mk
>>>> @@ -77,6 +77,12 @@ else
>>>> _CPU_LDFLAGS := $(CPU_LDFLAGS)
>>>> endif
>>>>
>>>> +# Translate DEPDIRS-y into LDLIBS
>>>> +IGNORE_DEPS = -lrte_eal/% -lrte_net -lrte_compat
>>>> +_LDDIRS = $(subst librte_ether,libethdev,$(DEPDIRS-y))
>>>> +_LDDEPS = $(subst lib/lib,-l,$(_LDDIRS))
>>>> +LDLIBS += $(filter-out $(IGNORE_DEPS), $(_LDDEPS))
>>>> +
>>>> O_TO_A = $(AR) crDs $(LIB) $(OBJS-y)
>>>> O_TO_A_STR = $(subst ','\'',$(O_TO_A)) #'# fix syntax highlight
>>>> O_TO_A_DISP = $(if $(V),"$(O_TO_A_STR)"," AR $(@)")
>>>>
>>>> I'm also sure somebody more familiar with gmake could improve it, but it
>>>> seems to work quite fine here. I'll wait a bit to see if there are other
>>>> suggestions before sending it as a proper patch.
>>>>
>>>> - Panu -
>>>>
>>
>> I did test the patch with minor diff in rte.vars.mk [1], otherwise all
>> libraries kept needed in final library.
>>
>> Patch itself looks good, overlinking problem in final binary seems fixed
>> [2] [3].
>>
>> But this cause a compilation error for cmdline_test [4]. This is because
>> of cyclic dependency between librte_eal <-> librte_mempool.
>>
>> Other applications don't have this compilation error because they use
>> librte_mempool, and since it is linked against application, this error
>> not observed. cmdline_test itself doesn't have any direct call to
>> librte_mempool.
>>
>> It is possible to add workaround to cmdline_test [5], (introduce
>> overlinking back), but should we attack on cyclic dependency instead?
>
> Cyclic dependencies are nasty, eliminating it would be good.
>
> But in the meanwhile it can be worked around in a generic manner by
> handling it in the libdpdk.so linker script, see
> http://dpdk.org/ml/archives/dev/2016-May/039413.html
>
Won't linker script has same problem, unless it is possible to select
some libraries to force link and some other to as-needed, than this can
be workaround, but I think using "--as-needed" as linker argument and
applying workaround to single test application is better.
Also when overlinking removed, getting compilation error for lpcap too.
Since -lpcap argument is before -lrte_pmd_pcap, symbols used by
rte_pmd_pcap not resolved, increasing --start-group scope fixes this.
Not related to overlinking, but while updating linker flags, as far as I
understand --whole-archive argument is only necessary for static pmd
libraries, but currently has wider scope, reducing its scope to pmd
slightly reduces final library sizes.
I will send a patch on top of your patch, with above updates.
Thanks,
ferruh
> - Panu -
>
>>
>> Thanks,
>> ferruh
>>
>> ---
>>
>> [1]
>> diff --git a/mk/exec-env/linuxapp/rte.vars.mk
>> b/mk/exec-env/linuxapp/rte.vars.mk
>> index d51bd17..10d37d5 100644
>> --- a/mk/exec-env/linuxapp/rte.vars.mk
>> +++ b/mk/exec-env/linuxapp/rte.vars.mk
>> @@ -46,7 +46,7 @@ EXECENV_CFLAGS = -pthread
>> endif
>>
>> # Workaround lack of DT_NEEDED entry
>> -EXECENV_LDFLAGS = --no-as-needed
>> +EXECENV_LDFLAGS = --as-needed
>>
>> EXECENV_LDLIBS =
>> EXECENV_ASFLAGS =
>>
>>
>> [2]
>> # ldd build/app/testpmd
>> linux-vdso.so.1 (0x00007ffcff92e000)
>> librte_mbuf.so.2.1 => .../build/lib/librte_mbuf.so.2.1
>> libethdev.so.4.1 => .../build/lib/libethdev.so.4.1
>> librte_mempool.so.2.1 => .../build/lib/librte_mempool.so.2.1
>> librte_ring.so.1.1 => .../build/lib/librte_ring.so.1.1
>> librte_eal.so.2.1 => .../build/lib/librte_eal.so.2.1
>> librte_cmdline.so.2.1 => .../build/lib/librte_cmdline.so.2.1
>> librte_pmd_bond.so.1.1 => .../build/lib/librte_pmd_bond.so.1.1
>> libpthread.so.0 => /lib64/libpthread.so.0 (0x00007f6879ff1000)
>> libc.so.6 => /lib64/libc.so.6 (0x00007f6879c30000)
>> /lib64/ld-linux-x86-64.so.2 (0x0000564998dbd000)
>> libdl.so.2 => /lib64/libdl.so.2 (0x00007f6879a2c000)
>> libgcc_s.so.1 => /lib64/libgcc_s.so.1 (0x00007f6879814000)
>> librt.so.1 => /lib64/librt.so.1 (0x00007f687960c000)
>> librte_kvargs.so.1.1 => .../build/lib/librte_kvargs.so.1.1
>>
>> [3]
>> # ldd -u -r build/app/testpmd
>> #
>>
>>
>> [4]
>> == Build app/cmdline_test
>> CC cmdline_test.o
>> CC commands.o
>> LD cmdline_test
>> .../build/lib/librte_eal.so: undefined reference to `rte_mempool_lookup'
>> .../build/lib/librte_eal.so: undefined reference to `rte_mempool_create'
>> collect2: error: ld returned 1 exit status
>> .../mk/rte.app.mk:243: recipe for target 'cmdline_test' failed
>> make[3]: *** [cmdline_test] Error 1
>>
>>
>> [5]
>> diff --git a/app/cmdline_test/Makefile b/app/cmdline_test/Makefile
>> index c6169f5..69ebfb2 100644
>> --- a/app/cmdline_test/Makefile
>> +++ b/app/cmdline_test/Makefile
>> @@ -46,6 +46,7 @@ SRCS-y += commands.c
>>
>> CFLAGS += -O3
>> CFLAGS += $(WERROR_FLAGS)
>> +LDFLAGS += --no-as-needed
>>
>> # this application needs libraries first
>> DEPDIRS-y += lib drivers
>>
>
next prev parent reply other threads:[~2016-05-27 16:15 UTC|newest]
Thread overview: 62+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-05-19 15:38 [dpdk-dev] Underlinked libs and overlinked applications - an issue? Christian Ehrhardt
2016-05-19 18:17 ` Thomas Monjalon
2016-05-20 11:01 ` Panu Matilainen
2016-05-20 12:41 ` Christian Ehrhardt
2016-05-20 16:43 ` Christian Ehrhardt
2016-05-20 16:50 ` [dpdk-dev] [PATCH] mk: fix underlinking issues of most librte libraries Christian Ehrhardt
2016-05-20 17:08 ` Thomas Monjalon
2016-05-24 9:56 ` Panu Matilainen
2016-05-24 10:11 ` Christian Ehrhardt
2016-05-26 13:13 ` Ferruh Yigit
2016-05-27 5:59 ` Panu Matilainen
2016-05-27 16:15 ` Ferruh Yigit [this message]
2016-05-27 16:48 ` [dpdk-dev] [PATCH 1/2] mk: prevent overlinking in applications Ferruh Yigit
2016-05-27 16:48 ` [dpdk-dev] [PATCH 2/2] mk: reduce scope of whole-archive to pmd libraries Ferruh Yigit
2016-06-10 9:03 ` Thomas Monjalon
2016-06-10 9:57 ` Ferruh Yigit
2016-06-10 10:18 ` Thomas Monjalon
2016-06-10 11:06 ` Ferruh Yigit
2016-06-10 12:21 ` Thomas Monjalon
2016-06-10 13:35 ` Ferruh Yigit
2016-06-09 10:10 ` [dpdk-dev] [PATCH 1/2] mk: prevent overlinking in applications Thomas Monjalon
2016-06-09 13:05 ` Ferruh Yigit
2016-06-10 13:19 ` [dpdk-dev] [PATCH v2 0/6] reduce " Thomas Monjalon
2016-06-10 13:19 ` [dpdk-dev] [PATCH v2 1/6] mk: sort drivers in static application link list Thomas Monjalon
2016-06-10 13:19 ` [dpdk-dev] [PATCH v2 2/6] mk: fix driver dependencies order for static application Thomas Monjalon
2016-06-10 14:49 ` Ferruh Yigit
2016-06-10 14:54 ` Thomas Monjalon
2016-06-10 13:19 ` [dpdk-dev] [PATCH v2 3/6] mk: remove library grouping during application linking Thomas Monjalon
2016-06-10 14:54 ` Ferruh Yigit
2016-06-10 15:14 ` Thomas Monjalon
2016-06-10 13:19 ` [dpdk-dev] [PATCH v2 4/6] mk: prevent overlinking in applications Thomas Monjalon
2016-06-10 14:56 ` Ferruh Yigit
2016-06-10 15:15 ` Thomas Monjalon
2016-06-10 13:19 ` [dpdk-dev] [PATCH v2 5/6] mk: sort libraries in level order when linking Thomas Monjalon
2016-06-10 13:19 ` [dpdk-dev] [PATCH v2 6/6] mk: reduce scope of whole-archive static linking Thomas Monjalon
2016-06-10 15:03 ` Ferruh Yigit
2016-06-10 15:18 ` Thomas Monjalon
2016-06-10 18:32 ` [dpdk-dev] [PATCH v3 0/6] reduce overlinking in applications Ferruh Yigit
2016-06-10 18:32 ` [dpdk-dev] [PATCH v3 1/6] mk: sort drivers in static application link list Ferruh Yigit
2016-06-10 19:38 ` Wiles, Keith
2016-06-10 18:32 ` [dpdk-dev] [PATCH v3 2/6] mk: fix driver dependencies order for static application Ferruh Yigit
2016-06-10 18:32 ` [dpdk-dev] [PATCH v3 3/6] mk: sort libraries when linking, move pmd libs to higher level Ferruh Yigit
2016-06-13 9:29 ` Thomas Monjalon
2016-06-13 10:04 ` Ferruh Yigit
2016-06-13 10:21 ` Thomas Monjalon
2016-06-13 10:29 ` Ferruh Yigit
2016-06-10 18:32 ` [dpdk-dev] [PATCH v3 4/6] mk: sort libraries when linking, move external libs to lower level Ferruh Yigit
2016-06-10 18:32 ` [dpdk-dev] [PATCH v3 5/6] mk: remove library grouping during application linking Ferruh Yigit
2016-06-10 18:32 ` [dpdk-dev] [PATCH v3 6/6] mk: prevent overlinking in applications Ferruh Yigit
2016-06-11 6:34 ` Thomas Monjalon
2016-06-13 9:05 ` Ferruh Yigit
2016-06-13 9:24 ` Christian Ehrhardt
2016-06-13 9:48 ` [dpdk-dev] [PATCH] mk: fix missing DEPDIRS to avoid libarary underlinking Christian Ehrhardt
2016-06-13 10:08 ` Thomas Monjalon
2016-06-13 10:20 ` Christian Ehrhardt
2016-06-13 11:06 ` [dpdk-dev] [PATCH v2 0/2] mk: fix more library underlinking Christian Ehrhardt
2016-06-13 11:06 ` [dpdk-dev] [PATCH v2 1/2] mk: fix missing vhost dependency to pthread to avoid libarary underlinking Christian Ehrhardt
2016-06-13 11:06 ` [dpdk-dev] [PATCH v2 2/2] mk: fix missing DEPDIRS " Christian Ehrhardt
2016-06-13 14:16 ` [dpdk-dev] [PATCH v2 0/2] mk: fix more library underlinking Thomas Monjalon
2016-06-13 14:14 ` [dpdk-dev] [PATCH v2 0/6] reduce overlinking in applications Thomas Monjalon
2016-06-07 8:23 ` [dpdk-dev] [PATCH] mk: fix underlinking issues of most librte libraries Thomas Monjalon
2016-06-07 9:25 ` Panu Matilainen
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