From: Luca Boccassi <lboccass@Brocade.com>
To: "thomas@monjalon.net" <thomas@monjalon.net>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v3 7/8] mk: sort object files when building deps lists
Date: Wed, 28 Jun 2017 14:49:11 +0000 [thread overview]
Message-ID: <1498661351.21465.8.camel@brocade.com> (raw)
In-Reply-To: <1711733.oN2V1mqmzG@xps>
On Wed, 2017-06-28 at 16:37 +0200, Thomas Monjalon wrote:
> 28/06/2017 16:07, Luca Boccassi:
> > On Tue, 2017-06-27 at 18:14 +0200, Thomas Monjalon wrote:
> > > 27/06/2017 16:51, Luca Boccassi:
> > > > On Tue, 2017-06-27 at 15:52 +0200, Thomas Monjalon wrote:
> > > > > 27/06/2017 12:43, Luca Boccassi:
> > > > > > On Tue, 2017-06-27 at 01:20 +0200, Thomas Monjalon wrote:
> > > > > > > 23/06/2017 20:41, lboccass@brocade.com:
> > > > > > > > From: Luca Boccassi <luca.boccassi@gmail.com>
> > > > > > > >
> > > > > > > > In order to achieve reproducible builds, always use the
> > > > > > > > same
> > > > > > > > order when listing object files to build dependencies
> > > > > > > > lists.
> > > > > > > >
> > > > > > > > Signed-off-by: Luca Boccassi <luca.boccassi@gmail.com>
> > > > > > > > ---
> > > > > > > > mk/rte.app.mk | 4 ++--
> > > > > > > > mk/rte.hostapp.mk | 4 ++--
> > > > > > > > mk/rte.shared.mk | 4 ++--
> > > > > > > > 3 files changed, 6 insertions(+), 6 deletions(-)
> > > > > > > >
> > > > > > > > --- a/mk/rte.app.mk
> > > > > > > > +++ b/mk/rte.app.mk
> > > > > > > > @@ -263,8 +263,8 @@ LDLIBS_NAMES += $(patsubst
> > > > > > > > -Wl$(comma)-
> > > > > > > > l%,lib%.a,$(filter -Wl$(comma)-l%,$(LDLIB
> > > > > > > >
> > > > > > > > # list of found libraries files (useful for deps). If
> > > > > > > > not
> > > > > > > > found,
> > > > > > > > the
> > > > > > > > # library is silently ignored and dep won't be checked
> > > > > > > > -LDLIBS_FILES := $(wildcard $(foreach
> > > > > > > > dir,$(LDLIBS_PATH),\
> > > > > > > > - $(addprefix $(dir)/,$(LDLIBS_NAMES))))
> > > > > > > > +LDLIBS_FILES := $(sort $(wildcard $(foreach
> > > > > > > > dir,$(LDLIBS_PATH),\
> > > > > > > > + $(addprefix $(dir)/,$(LDLIBS_NAMES)))))
> > > > > > >
> > > > > > > You cannot sort libraries.
> > > > > > > Check - for instance - this comment above in this file:
> > > > > > > # Eliminate duplicates without sorting, only keep the
> > > > > > > last
> > > > > > > occurrence
> > > > > > > filter-libs = \
> > > > > >
> > > > > > Not sure I follow - what's the reason for avoiding to sort
> > > > > > the
> > > > > > list
> > > > > > of
> > > > > > libs to link against?
> > > > >
> > > > > Sorry, the ordering issue is with LDLIBS not LDLIBS_FILES.
> > > > >
> > > > > > > Why sorting them?
> > > > > > > What is random in libraries list?
> > > > > >
> > > > > > The issue is that the output of wildcard is not fully
> > > > > > deterministic. It
> > > > > > can depend on the filesystem, and even on the locale
> > > > > > settings
> > > > > > [1].
> > > > > > Before GNU Make 3.82 (2009) it used to automatically sort
> > > > > > the
> > > > > > output,
> > > > > > but that was removed (to make it faster... sigh). [2]
> > > > >
> > > > > It is not a true wildcard here. It is just filtering files
> > > > > which
> > > > > do not exist.
> > > > > I think you do not need this patch for deterministic build.
> > > >
> > > > But then those lists are passed down in the .SECONDEXPANSION
> > > > rule
> > > > right?
> > >
> > > I do not follow you.
> > > Please explain what is the benefit of the patch in the next
> > > version.
> >
> > I thought that these lists are used to determine which files to
> > recompile - and incidentally, in which order as they are passed in
> > this
> > snippet in rte.compile-pre.mk:
> >
> > .SECONDEXPANSION:
> > %.o: %.c $$(wildcard $$(dep_$$@)) $$(DEP_$$(@)) FORCE
> > @[ -d $(dir $@) ] || mkdir -p $(dir $@)
> > $(if $(D),\
> > @echo -n "$< -> $@ " ; \
> > echo -n "file_missing=$(call boolean,$(file_missing)) "
> > ; \
> > echo -n "cmdline_changed=$(call boolean,$(call
> > cmdline_changed,$(C_TO_O))) " ; \
> > echo -n "depfile_missing=$(call
> > boolean,$(depfile_missing)) " ; \
> > echo "depfile_newer=$(call boolean,$(depfile_newer))")
> > $(if $(or \
> > $(file_missing),\
> > $(call cmdline_changed,$(C_TO_O)),\
> > $(depfile_missing),\
> > $(depfile_newer)),\
> > $(C_TO_O_DO))
> >
> > Did I get that wrong? (It is a bit convoluted :-P )
>
> LDLIBS_FILES are just used to link the executable AFAIK.
> The libraries are built in separate recursive make calls.
>
> > But nevertheless, I've finally found the root cause for the
> > "wandering
> > header" - when building the libraries, CFLAGS lists
> > -I$(RTE_OUTDIR)/include first and then -I$(SRCDIR) last. There is a
> > race, and sometimes when GCC is called the public header has
> > already
> > been installed in RTE_OUTDIR and sometimes it has not. This causes
> > the
> > instability, and causes the expansion of __FILE__ and the directory
> > listing in the DWARF objects to randomly list the full path to
> > either
> > RTE_OUTDIR/include or SRCDIR for each library.
> >
> > By always passing -I$(SRCDIR) first this instability is solved.
>
> Good news.
BTW as an example here's the diff between 2 builds, if anyone is
interested:
https://paste.debian.net/973727/
--
Kind regards,
Luca Boccassi
next prev parent reply other threads:[~2017-06-28 14:50 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-22 13:58 [dpdk-dev] [PATCH 0/4] reproducible builds - docs and linker script lboccass
2017-06-22 13:58 ` [dpdk-dev] [PATCH 1/4] mk: use make silent flag to print HTML doc version lboccass
2017-06-22 13:58 ` [dpdk-dev] [PATCH 2/4] mk: fix excluding .doctrees when installing docs lboccass
2017-06-22 13:58 ` [dpdk-dev] [PATCH 3/4] mk: sort list of shared objects in linker script lboccass
2017-06-22 13:58 ` [dpdk-dev] [PATCH 4/4] mk: sort list of files in examples.dox lboccass
2017-06-23 18:16 ` [dpdk-dev] [PATCH v2 0/7] Reproducible build lboccass
2017-06-23 18:16 ` [dpdk-dev] [PATCH v2 1/7] mk: fix excluding .doctrees when installing docs lboccass
2017-06-23 18:16 ` [dpdk-dev] [PATCH v2 2/7] mk: sort list of shared objects in linker script lboccass
2017-06-23 18:16 ` [dpdk-dev] [PATCH v2 3/7] mk: sort list of files in examples.dox lboccass
2017-06-23 18:16 ` [dpdk-dev] [PATCH v2 4/7] mk: sort headers before wildcard inclusion lboccass
2017-06-23 18:33 ` [dpdk-dev] [PATCH v2 5/7] mk: sort source files before passing them to the compiler lboccass
2017-06-23 18:33 ` [dpdk-dev] [PATCH v2 6/7] mk: sort object files when building deps lists lboccass
2017-06-23 18:33 ` [dpdk-dev] [PATCH v2 7/7] mk: always rebuild in the same order lboccass
2017-06-23 18:41 ` [dpdk-dev] [PATCH v2 0/7] Reproducible build Luca Boccassi
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 0/8] " lboccass
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 1/8] mk: use make silent flag to print HTML doc version lboccass
2017-06-26 14:45 ` Mcnamara, John
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 2/8] mk: fix excluding .doctrees when installing docs lboccass
2017-06-26 14:46 ` Mcnamara, John
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 3/8] mk: sort list of shared objects in linker script lboccass
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 4/8] mk: sort list of files in examples.dox lboccass
2017-06-26 14:48 ` Mcnamara, John
2017-06-26 14:56 ` Mcnamara, John
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 5/8] mk: sort headers before wildcard inclusion lboccass
2017-06-26 14:49 ` Mcnamara, John
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 6/8] mk: sort source files before passing them to the compiler lboccass
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 7/8] mk: sort object files when building deps lists lboccass
2017-06-26 23:20 ` Thomas Monjalon
2017-06-27 10:43 ` Luca Boccassi
2017-06-27 13:52 ` Thomas Monjalon
2017-06-27 14:51 ` Luca Boccassi
2017-06-27 16:14 ` Thomas Monjalon
2017-06-28 14:07 ` Luca Boccassi
2017-06-28 14:37 ` Thomas Monjalon
2017-06-28 14:49 ` Luca Boccassi [this message]
2017-06-23 18:41 ` [dpdk-dev] [PATCH v3 8/8] mk: always rebuild in the same order lboccass
2017-06-26 23:22 ` Thomas Monjalon
2017-06-27 10:36 ` Luca Boccassi
2017-06-26 22:11 ` [dpdk-dev] [PATCH v3 0/8] Reproducible build Thomas Monjalon
2017-06-26 23:15 ` Thomas Monjalon
2017-06-28 13:56 ` [dpdk-dev] [PATCH v4 0/6] " lboccass
2017-06-28 13:56 ` [dpdk-dev] [PATCH v4 1/6] mk: sort list of shared objects in linker script lboccass
2017-06-28 13:56 ` [dpdk-dev] [PATCH v4 2/6] mk: sort list of files in examples.dox lboccass
2017-06-28 13:56 ` [dpdk-dev] [PATCH v4 3/6] mk: sort headers before wildcard inclusion lboccass
2017-06-28 13:57 ` [dpdk-dev] [PATCH v4 4/6] mk: sort source files before passing them to the compiler lboccass
2017-06-28 13:57 ` [dpdk-dev] [PATCH v4 5/6] mk: sort object files when building deps lists lboccass
2017-06-28 13:57 ` [dpdk-dev] [PATCH v4 6/6] mk: set -ISCDIR before -IRTE_OUT/include in CFLAGS lboccass
2017-06-28 15:57 ` [dpdk-dev] [PATCH v4 0/6] Reproducible build Stephen Hemminger
2017-06-28 16:04 ` Bruce Richardson
2017-06-28 17:52 ` Luca Boccassi
2017-08-11 12:43 ` Luca Boccassi
2017-08-10 18:23 ` [dpdk-dev] [PATCH v5 " luca.boccassi
2017-08-10 18:23 ` [dpdk-dev] [PATCH v5 1/6] mk: sort list of shared objects in linker script luca.boccassi
2017-08-10 18:23 ` [dpdk-dev] [PATCH v5 2/6] mk: sort list of files in examples.dox luca.boccassi
2017-08-10 18:23 ` [dpdk-dev] [PATCH v5 3/6] mk: sort headers before wildcard inclusion luca.boccassi
2017-08-10 18:23 ` [dpdk-dev] [PATCH v5 4/6] mk: sort source files before passing them to the compiler luca.boccassi
2017-08-10 18:23 ` [dpdk-dev] [PATCH v5 5/6] mk: sort object files when building deps lists luca.boccassi
2017-08-10 18:23 ` [dpdk-dev] [PATCH v5 6/6] mk: set -ISCDIR before -IRTE_OUT/include in CFLAGS luca.boccassi
2017-08-18 11:03 ` [dpdk-dev] [PATCH v6 0/6] Reproducible build luca.boccassi
2017-08-18 11:03 ` [dpdk-dev] [PATCH v6 1/6] mk: sort list of shared objects in linker script luca.boccassi
2017-08-18 11:03 ` [dpdk-dev] [PATCH v6 2/6] mk: sort list of files in examples.dox luca.boccassi
2017-08-18 11:03 ` [dpdk-dev] [PATCH v6 3/6] mk: sort headers before wildcard inclusion luca.boccassi
2017-08-18 11:03 ` [dpdk-dev] [PATCH v6 4/6] mk: sort source files before passing them to the compiler luca.boccassi
2017-08-18 11:03 ` [dpdk-dev] [PATCH v6 5/6] mk: sort object files when building deps lists luca.boccassi
2017-08-18 11:03 ` [dpdk-dev] [PATCH v6 6/6] mk: set -ISCDIR before -IRTE_OUT/include in CFLAGS luca.boccassi
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