Re: [dpdk-dev] [PATCH v7 1/6] Move common functions in eal_thread.c

[Neil Horman <nhorman@tuxdriver.com>]

On Sat, Apr 25, 2015 at 08:32:42AM -0400, Neil Horman wrote:
> On Fri, Apr 24, 2015 at 06:45:06PM -0700, Ravi Kerur wrote:
> > On Fri, Apr 24, 2015 at 2:24 PM, Ravi Kerur <rkerur@gmail.com> wrote:
> > 
> > >
> > >
> > > On Fri, Apr 24, 2015 at 12:51 PM, Neil Horman <nhorman@tuxdriver.com>
> > > wrote:
> > >
> > >> On Fri, Apr 24, 2015 at 12:21:23PM -0700, Ravi Kerur wrote:
> > >> > On Fri, Apr 24, 2015 at 11:53 AM, Neil Horman <nhorman@tuxdriver.com>
> > >> wrote:
> > >> >
> > >> > > On Fri, Apr 24, 2015 at 09:45:24AM -0700, Ravi Kerur wrote:
> > >> > > > On Fri, Apr 24, 2015 at 8:22 AM, Neil Horman <nhorman@tuxdriver.com
> > >> >
> > >> > > wrote:
> > >> > > >
> > >> > > > > On Fri, Apr 24, 2015 at 08:14:04AM -0700, Ravi Kerur wrote:
> > >> > > > > > On Fri, Apr 24, 2015 at 6:51 AM, Neil Horman <
> > >> nhorman@tuxdriver.com>
> > >> > > > > wrote:
> > >> > > > > >
> > >> > > > > > > On Thu, Apr 23, 2015 at 02:35:31PM -0700, Ravi Kerur wrote:
> > >> > > > > > > > Changes in v7
> > >> > > > > > > > Remove _setname_ pthread calls.
> > >> > > > > > > > Use rte_gettid() API in RTE_LOG to print thread_id.
> > >> > > > > > > >
> > >> > > > > > > > Changes in v6
> > >> > > > > > > > Remove RTE_EXEC_ENV_BSDAPP from eal_common_thread.c file.
> > >> > > > > > > > Add pthread_setname_np/pthread_set_name_np for Linux/FreeBSD
> > >> > > > > > > > respectively. Plan to use _getname_ in RTE_LOG when
> > >> available.
> > >> > > > > > > > Use existing rte_get_systid() in RTE_LOG to print thread_id.
> > >> > > > > > > >
> > >> > > > > > > > Changes in v5
> > >> > > > > > > > Rebase to latest code.
> > >> > > > > > > >
> > >> > > > > > > > Changes in v4
> > >> > > > > > > > None
> > >> > > > > > > >
> > >> > > > > > > > Changes in v3
> > >> > > > > > > > Changed subject to be more explicit on file name inclusion.
> > >> > > > > > > >
> > >> > > > > > > > Changes in v2
> > >> > > > > > > > None
> > >> > > > > > > >
> > >> > > > > > > > Changes in v1
> > >> > > > > > > > eal_thread.c has minor differences between Linux and BSD,
> > >> move
> > >> > > > > > > > entire file into common directory.
> > >> > > > > > > > Use RTE_EXEC_ENV_BSDAPP to differentiate on minor
> > >> differences.
> > >> > > > > > > > Rename eal_thread.c to eal_common_thread.c
> > >> > > > > > > > Makefile changes to reflect file move and name change.
> > >> > > > > > > > Fix checkpatch warnings.
> > >> > > > > > > >
> > >> > > > > > > > Signed-off-by: Ravi Kerur <rkerur@gmail.com>
> > >> > > > > > > > ---
> > >> > > > > > > >  lib/librte_eal/bsdapp/eal/Makefile        |   2 +-
> > >> > > > > > > >  lib/librte_eal/bsdapp/eal/eal_thread.c    | 152
> > >> > > > > > > ------------------------------
> > >> > > > > > > >  lib/librte_eal/common/eal_common_thread.c | 147
> > >> > > > > > > ++++++++++++++++++++++++++++-
> > >> > > > > > > >  lib/librte_eal/linuxapp/eal/eal_thread.c  | 152
> > >> > > > > > > +-----------------------------
> > >> > > > > > > >  4 files changed, 148 insertions(+), 305 deletions(-)
> > >> > > > > > > >
> > >> > > > > > > > diff --git a/lib/librte_eal/bsdapp/eal/Makefile
> > >> > > > > > > b/lib/librte_eal/bsdapp/eal/Makefile
> > >> > > > > > > > index 2357cfa..55971b9 100644
> > >> > > > > > > > --- a/lib/librte_eal/bsdapp/eal/Makefile
> > >> > > > > > > > +++ b/lib/librte_eal/bsdapp/eal/Makefile
> > >> > > > > > > > @@ -87,7 +87,7 @@ CFLAGS_eal_common_log.o := -D_GNU_SOURCE
> > >> > > > > > > >  # workaround for a gcc bug with noreturn attribute
> > >> > > > > > > >  # http://gcc.gnu.org/bugzilla/show_bug.cgi?id=12603
> > >> > > > > > > >  ifeq ($(CONFIG_RTE_TOOLCHAIN_GCC),y)
> > >> > > > > > > > -CFLAGS_eal_thread.o += -Wno-return-type
> > >> > > > > > > > +CFLAGS_eal_common_thread.o += -Wno-return-type
> > >> > > > > > > >  CFLAGS_eal_hpet.o += -Wno-return-type
> > >> > > > > > > >  endif
> > >> > > > > > > >
> > >> > > > > > > > diff --git a/lib/librte_eal/bsdapp/eal/eal_thread.c
> > >> > > > > > > b/lib/librte_eal/bsdapp/eal/eal_thread.c
> > >> > > > > > > > index 9a03437..5714b8f 100644
> > >> > > > > > > > --- a/lib/librte_eal/bsdapp/eal/eal_thread.c
> > >> > > > > > > > +++ b/lib/librte_eal/bsdapp/eal/eal_thread.c
> > >> > > > > > > > @@ -35,163 +35,11 @@
> > >> > > > > > > >  #include <stdio.h>
> > >> > > > > > > >  #include <stdlib.h>
> > >> > > > > > > >  #include <stdint.h>
> > >> > > > > > > > -#include <unistd.h>
> > >> > > > > > > > -#include <sched.h>
> > >> > > > > > > > -#include <pthread_np.h>
> > >> > > > > > > > -#include <sys/queue.h>
> > >> > > > > > > >  #include <sys/thr.h>
> > >> > > > > > > >
> > >> > > > > > > > -#include <rte_debug.h>
> > >> > > > > > > > -#include <rte_atomic.h>
> > >> > > > > > > > -#include <rte_launch.h>
> > >> > > > > > > > -#include <rte_log.h>
> > >> > > > > > > > -#include <rte_memory.h>
> > >> > > > > > > > -#include <rte_memzone.h>
> > >> > > > > > > > -#include <rte_per_lcore.h>
> > >> > > > > > > > -#include <rte_eal.h>
> > >> > > > > > > > -#include <rte_per_lcore.h>
> > >> > > > > > > > -#include <rte_lcore.h>
> > >> > > > > > > > -
> > >> > > > > > > >  #include "eal_private.h"
> > >> > > > > > > >  #include "eal_thread.h"
> > >> > > > > > > >
> > >> > > > > > > > -RTE_DEFINE_PER_LCORE(unsigned, _lcore_id) = LCORE_ID_ANY;
> > >> > > > > > > NAK, these are exported symbols, you can't remove them without
> > >> > > going
> > >> > > > > > > through the
> > >> > > > > > > deprecation process.
> > >> > > > > > >
> > >> > > > > > >
> > >> > > > > > They are not removed/deleted, they are moved from eal_thread.c
> > >> to
> > >> > > > > > eal_common_thread.c file since it is common to both Linux and
> > >> BSD.
> > >> > > > > >
> > >> > > > > Then perhaps you forgot to export the symbol?  Its showing up as
> > >> > > removed
> > >> > > > > on the
> > >> > > > > ABI checker utility.
> > >> > > > >
> > >> > > > > Neil
> > >> > > > >
> > >> > > >
> > >> > > > Can you please show me in the current code where it is being
> > >> exported? I
> > >> > > > have only moved definitions to _common_ files, not sure why it
> > >> should be
> > >> > > > exported now.  I searched in the current code for
> > >> RTE_DEFINE_PER_LCORE
> > >> > > >
> > >> > > > #home/rkerur/dpdk-tmp/dpdk# grep -ir RTE_DEFINE_PER_LCORE *
> > >> > > > app/test/test_per_lcore.c:static RTE_DEFINE_PER_LCORE(unsigned,
> > >> test) =
> > >> > > > 0x12345678;
> > >> > > >
> > >> lib/librte_eal/linuxapp/eal/eal_thread.c:RTE_DEFINE_PER_LCORE(unsigned,
> > >> > > > _lcore_id) = LCORE_ID_ANY;
> > >> > > >
> > >> lib/librte_eal/linuxapp/eal/eal_thread.c:RTE_DEFINE_PER_LCORE(unsigned,
> > >> > > > _socket_id) = (unsigned)SOCKET_ID_ANY;
> > >> > > >
> > >> > >
> > >> lib/librte_eal/linuxapp/eal/eal_thread.c:RTE_DEFINE_PER_LCORE(rte_cpuset_t,
> > >> > > > _cpuset);
> > >> > > >
> > >> lib/librte_eal/bsdapp/eal/eal_thread.c:RTE_DEFINE_PER_LCORE(unsigned,
> > >> > > > _lcore_id) = LCORE_ID_ANY;
> > >> > > >
> > >> lib/librte_eal/bsdapp/eal/eal_thread.c:RTE_DEFINE_PER_LCORE(unsigned,
> > >> > > > _socket_id) = (unsigned)SOCKET_ID_ANY;
> > >> > > >
> > >> lib/librte_eal/bsdapp/eal/eal_thread.c:RTE_DEFINE_PER_LCORE(rte_cpuset_t,
> > >> > > > _cpuset);
> > >> > > > lib/librte_eal/common/include/rte_per_lcore.h:#define
> > >> > > > RTE_DEFINE_PER_LCORE(type, name)            \
> > >> > > > lib/librte_eal/common/include/rte_eal.h:    static
> > >> > > > RTE_DEFINE_PER_LCORE(int, _thread_id) = -1;
> > >> > > > lib/librte_eal/common/eal_common_errno.c:RTE_DEFINE_PER_LCORE(int,
> > >> > > > _rte_errno);
> > >> > > > lib/librte_eal/common/eal_common_errno.c:    static
> > >> > > > RTE_DEFINE_PER_LCORE(char[RETVAL_SZ], retval);
> > >> > > >
> > >> > > >
> > >> > > > > > Thanks
> > >> > > > > > Ravi
> > >> > > > > >
> > >> > > > > > Regards
> > >> > > > > > > Neil
> > >> > > > > > >
> > >> > > > > > >
> > >> > > > >
> > >> > > Its exported in the version map file:
> > >> > >  per_lcore__lcore_id;
> > >> > >
> > >> > >
> > >> > Thanks Neil, I checked and both linux and bsd rte_eal_version.map have
> > >> it.
> > >> > I compared .map file between "changed code" and the original, they are
> > >> same
> > >> > for both linux and bsd. In fact you had ACK'd v4 version of this patch
> > >> > series and no major changes after that. Please let me know if I missed
> > >> > something.
> > >> >
> > >> I did, and I'm retracting that, because I didn't think to check the ABI
> > >> compatibility on this.  But I ran it throught the ABI checking script
> > >> this and
> > >> this error popped out.  You should run it as well, its in the scripts
> > >> directory.
> > >>
> > >>
> > >> I see in your first patch you removed it and re-added it in the common
> > >> section.
> > >> But something about how its building is causing it to not show up as an
> > >> exported
> > >> symbol, which is problematic, as other applications are going to want
> > >> access to
> > >> it.
> > >>
> > >> It also possible that the ABI checker is throwing a false positive, but
> > >> either
> > >> way, it needs to be looked into prior to moving forward with this.
> > >>
> > >>
> > > I did following things.
> > >
> > > Put a tag (v2.0.0-before-common-eal)  before EAL common functions changes
> > > for commit (3c0c807038ad642f4be7deb9370293c39d12f029 net: remove unneeded
> > > include)
> > >
> > > Put a tag (v2.0.0-common-eal) after EAL common functions changes for
> > > commit (25737e5a7212630a7b5d8ca756860a062f403789 Move common functions in
> > > eal_pci.c)
> > >
> > > Ran validate-abi against x86_64-native-linuxapp-gcc and
> > >
> > > v2.0.0-rc3 and v2.0.0-before-common-eal, html report for librte_eal.so
> > > shows removed symbols for "per_lcore__cpuset"
> > >
> > > v2.0.0-rc3 and v2.0.0-common-eal, html report for librte_eal.so shows
> > > removed symbols for "per_lcore__cpuset"
> > >
> > > Removed symbol is different from what you have reported and in my case I
> > > see it even before my commit. If you are interested I can unicast you html
> > > report file. Please let me know how to proceed.
> > >
> > >
> > 
> > I did some experiment and found some interesting things.  I will take eal.c
> > as an example
> > 
> > eal.c is split into eal_common_sysfs.c eal_common_mem_cfg.c
> > eal_common_proc_type.c and eal_common_app_usage.c. In linuxapp/eal/Makefile
> > if I compile new files right after eal.c as shown below
> > 
> > SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) := eal.c
> > SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_sysfs.c
> > SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_mem_cfg.c
> > SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_proc_type.c
> > SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_app_usage.c
> > ...
> > 
> > validate-abi results matches baseline. Instead if i place new _common_
> > files in common area in linuxapp/eal/Makefile as shown below
> > 
> > # from common dir
> > SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_memzone.c
> > SRCS-$(CONFIG_RTE_LIBRTE_EAL_LINUXAPP) += eal_common_log.c
> > ...
> > 
> > validate-abi reports problem in binary compatibility and source
> > compatiblity
> > 
> > eal_filesystem.h, librte_eal.so.1
> >  [+] eal_parse_sysfs_value ( char const* filename, unsigned long* val )
> >  @@ DPDK_2.0 (2)
> > 
> > I believe files in common and linuxapp directory are compiled same way so
> > not sure why placement in makefile makes difference.
> > 
> > Could this be false-positive from validate-abi script??
> > 
> It could be, yes.  Though I'm more inclined to think that perhaps in the new
> version of the code we're not generating ithe same dwarf information out of it.
> In fact for some reason, I've checked both the build before and after your
> patch series, and the exported CFLAGS aren't getting passed to the build
> properly, implying that we're not building all the code in the validator with
> the -g flag, which the validator need to function properly.  I'm looking into
> that
> Neil
> 
> 
Found the problem, I was stupidly reading the report incorrectly.  The problem
regarding _lcore_id is a source compatibilty issue (because the symbol moved to
a new location), which is irrelevant to us.  Its not in any way a binary compat
problem, which is what we care about.  Sorry for the noise.

I do still have a few concerns about some changed calling conventions with a few
other functions, which I'll look into on monday.

Regards
Neil