From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Thomas Monjalon <thomas.monjalon@6wind.com>
Cc: dev@dpdk.org, Panu Matilainen <pmatilai@redhat.com>,
Christian Ehrhardt <christian.ehrhardt@canonical.com>
Subject: Re: [dpdk-dev] [PATCH 1/2] mk: prevent overlinking in applications
Date: Thu, 9 Jun 2016 14:05:13 +0100 [thread overview]
Message-ID: <57596989.50601@intel.com> (raw)
In-Reply-To: <7354386.zBuGXxEf9j@xps13>
On 6/9/2016 11:10 AM, Thomas Monjalon wrote:
> Hi Ferruh,
>
> 2016-05-27 17:48, Ferruh Yigit:
>> Replace --no-as-needed linker flag with --as-needed flag, which will
>> only link libraries directly called by application. This requires inter
>> library dependencies resolved correctly.
>>
>> Not linking all libraries cause a compile error for lpcap and possible
>> to have other similar compiler errors, so increasing the scope of
>> --start-group argument.
>
> What is the error?
>
This is with -as-needed flag, and static library compilation:
.../dpdk/build/lib/librte_pmd_pcap.a(rte_eth_pcap.o): In function
`eth_dev_stop':
rte_eth_pcap.c:(.text+0xcc1): undefined reference to `pcap_dump_close'
rte_eth_pcap.c:(.text+0xcd6): undefined reference to `pcap_close'
rte_eth_pcap.c:(.text+0xd19): undefined reference to `pcap_close'
rte_eth_pcap.c:(.text+0xd58): undefined reference to `pcap_close'
/root/development/dpdk/build/lib/librte_pmd_pcap.a(rte_eth_pcap.o): In
function `open_tx_pcap':
rte_eth_pcap.c:(.text+0x190b): undefined reference to `pcap_open_dead'
rte_eth_pcap.c:(.text+0x191b): undefined reference to `pcap_dump_open'
...
pcap pmd has libpcap calls, but while linking final application
(testpmd), linker is not able to find objects that has these.
The command line for compilation is:
gcc ... -o test ... -Wl,--whole-archive <dpdk libs> -Wl,-lpcap
-Wl,--start-group <more dpdk libs> -Wl,-lrte_pmd_pcap <more dpdk libs>
-Wl,--end-group -Wl,--no-whole-archive
-lpcap is provided, but since before -lrte_pmd_pcap, references not
resolved.
Previously, with "-no-as-needed" flag, all shared libraries linked
always, which was preventing compile error.
>> cmdline_test application causes compile error because of cyclic
>> dependency between librte_eal <-> librte_mempool. A workaround added to
>> cmdline_test for compile error.
>>
>> Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
>
>> --- a/app/cmdline_test/Makefile
>> +++ b/app/cmdline_test/Makefile
>> @@ -46,6 +46,7 @@ SRCS-y += commands.c
>>
>> CFLAGS += -O3
>> CFLAGS += $(WERROR_FLAGS)
>
> A comment is required here to explain the workaround.
>
Sure, I will add a comment and send a new version of the patch.
>> +LDFLAGS += -no-as-needed
>
> The option should be --no-as-needed.
Right
>
>> --- a/mk/exec-env/linuxapp/rte.vars.mk
>> +++ b/mk/exec-env/linuxapp/rte.vars.mk
>> @@ -46,7 +46,7 @@ EXECENV_CFLAGS = -pthread
>> endif
>>
>> # Workaround lack of DT_NEEDED entry
>
> This comment is obsolete now.
Will remove.
>
>> -EXECENV_LDFLAGS = --no-as-needed
>> +EXECENV_LDFLAGS = --as-needed
>
> Why put this option for Linux only?
When this option not defined at all, different compilers behave
different, some has --as-needed as default and cause compilation issues,
I guess that is why for Linux --no-as-needed is forces. I assume BSD
compilers by default use --no-as-needed, so we don't have any
compilation problem.
And it looks like there is no specific reason to not force BSD to
--as-needed, I will test it.
> Shouldn't we restrict this option to app.mk only?
Having --no-needed flag only for app should be OK. Let me test first,
and as a result should we move this to app.mk?
>
>> --- a/mk/rte.app.mk
>> +++ b/mk/rte.app.mk
>> @@ -58,6 +58,7 @@ _LDLIBS-y += -L$(RTE_SDK_BIN)/lib
>> #
>>
>> _LDLIBS-y += --whole-archive
>> +_LDLIBS-y += --start-group
>
> --start-group must be used only to solve circular dependencies.
> Ideally we should not use it. I think it's needed only because
> of EAL logs using mempool (must be removed).
No, this is not the reason, please check above lpcap compile error, that
is the reason of this update.
> Why extending it?
> I'm afraid we are masking some issues.
But if we have a convention to add external libraries after dpdk
libraries, that also should solve this issue, but that is more update
than just updating --start-group.
>
>> _LDLIBS-$(CONFIG_RTE_LIBRTE_DISTRIBUTOR) += -lrte_distributor
>> _LDLIBS-$(CONFIG_RTE_LIBRTE_REORDER) += -lrte_reorder
>> @@ -111,8 +112,6 @@ _LDLIBS-y += -lcrypto
>> endif
>> endif # !CONFIG_RTE_BUILD_SHARED_LIBS
>>
>> -_LDLIBS-y += --start-group
>> -
>> _LDLIBS-$(CONFIG_RTE_LIBRTE_KVARGS) += -lrte_kvargs
>> _LDLIBS-$(CONFIG_RTE_LIBRTE_MBUF) += -lrte_mbuf
>> _LDLIBS-$(CONFIG_RTE_LIBRTE_IP_FRAG) += -lrte_ip_frag
>
next prev parent reply other threads:[~2016-06-09 13:06 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
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 [this message]
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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