| Message ID | 1419239071-4637-1-git-send-email-fhunleth@troodon-software.com |
|---|---|
| State | Superseded |
| Headers | show |
Franck, All, On 2014-12-22 04:04 -0500, Frank Hunleth spake thusly: > Erlang can use either the system libatomic_ops or its own version. > However, if using the system version, it must find implementations for > AO_compare_and_swap() and other calls. Since these are not available on > all platforms, selectively enable the use of the system libatomic_ops. > > Fixes: > http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/ > http://autobuild.buildroot.net/results/c74/c743cfca629fb332bbb1327cf4ea360f0a4e4bfe/ > http://autobuild.buildroot.net/results/095/095348d4d309c2a408a3b297b4325348ed1dd7e8/ > > Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com> > --- > package/erlang/Config.in | 10 ++++++++++ > package/erlang/erlang.mk | 4 +++- > 2 files changed, 13 insertions(+), 1 deletion(-) > > diff --git a/package/erlang/Config.in b/package/erlang/Config.in > index 56830da..9caf1ec 100644 > --- a/package/erlang/Config.in > +++ b/package/erlang/Config.in > @@ -26,6 +26,16 @@ config BR2_PACKAGE_ERLANG_SMP > If you do not need SMP support, turning this option off reduces > compile time and the size of the Erlang installation. > > +config BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS > + bool > + select BR2_PACKAGE_LIBATOMIC_OPS > + default y if BR2_ARM_CPU_ARMV7A || BR2_x86_64 Well, we already have BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS that defines which architecture libatomic_ops supports. So, unless AO_compare_and_swap() is not available on all those architectures (and it seems it is), you should use that symbol instead. > + help > + Use the system libatomic_ops on platforms that provide > + implementations for AO_store(), AO_load(), and AO_compare_and_swap(). > + Platforms without support for those functions must still use the > + Erlang-provided implementation. > + > config BR2_PACKAGE_ERLANG_MEGACO > bool "install megaco application" > help > diff --git a/package/erlang/erlang.mk b/package/erlang/erlang.mk > index 0b8619e..007053a 100644 > --- a/package/erlang/erlang.mk > +++ b/package/erlang/erlang.mk > @@ -22,9 +22,11 @@ ERLANG_CONF_ENV += erl_xcomp_sysroot=$(STAGING_DIR) > > ERLANG_CONF_OPTS = --without-javac > > -ifeq ($(BR2_PACKAGE_LIBATOMIC_OPS),y) > +ifeq ($(BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS),y) > ERLANG_DEPENDENCIES += libatomic_ops > ERLANG_CONF_OPTS += --with-libatomic_ops=$(STAGING_DIR)/usr > +else > +ERLANG_CONF_OPTS += --without-libatomic_ops > endif So the consition for this block should stay the same, but the --without-libatomic_ops addition is still welcome. Regards, Yann E. MORIN. > # erlang uses openssl for all things crypto. Since the host tools (such as > -- > 1.9.1 > > _______________________________________________ > buildroot mailing list > buildroot@busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot
Hi Yann, On Mon, Dec 22, 2014 at 12:13 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote: > Franck, All, > > On 2014-12-22 04:04 -0500, Frank Hunleth spake thusly: >> Erlang can use either the system libatomic_ops or its own version. >> However, if using the system version, it must find implementations for >> AO_compare_and_swap() and other calls. Since these are not available on >> all platforms, selectively enable the use of the system libatomic_ops. >> >> Fixes: >> http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/ >> http://autobuild.buildroot.net/results/c74/c743cfca629fb332bbb1327cf4ea360f0a4e4bfe/ >> http://autobuild.buildroot.net/results/095/095348d4d309c2a408a3b297b4325348ed1dd7e8/ >> >> Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com> >> --- >> package/erlang/Config.in | 10 ++++++++++ >> package/erlang/erlang.mk | 4 +++- >> 2 files changed, 13 insertions(+), 1 deletion(-) >> >> diff --git a/package/erlang/Config.in b/package/erlang/Config.in >> index 56830da..9caf1ec 100644 >> --- a/package/erlang/Config.in >> +++ b/package/erlang/Config.in >> @@ -26,6 +26,16 @@ config BR2_PACKAGE_ERLANG_SMP >> If you do not need SMP support, turning this option off reduces >> compile time and the size of the Erlang installation. >> >> +config BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS >> + bool >> + select BR2_PACKAGE_LIBATOMIC_OPS >> + default y if BR2_ARM_CPU_ARMV7A || BR2_x86_64 > > Well, we already have BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS that defines > which architecture libatomic_ops supports. > > So, unless AO_compare_and_swap() is not available on all those > architectures (and it seems it is), you should use that symbol instead. That was my first thought, but if you look at the configs for the failed builds, BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS=y is defined. E.g.: http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/config Unfortunately, configure only prints the following to the build log so it's not immediately obvious which function was missing: checking for a usable libatomic_ops implementation... no configure: error: No usable libatomic_ops implementation found My assumption is that AO_compare_and_swap() is missing since that's what I saw on a BR2_ARM_CPU_ARMV4 platform, but it could be something else on BR2_ARM_CPU_ARMV5 (the config that I referenced above). Thanks, Frank > >> + help >> + Use the system libatomic_ops on platforms that provide >> + implementations for AO_store(), AO_load(), and AO_compare_and_swap(). >> + Platforms without support for those functions must still use the >> + Erlang-provided implementation. >> + >> config BR2_PACKAGE_ERLANG_MEGACO >> bool "install megaco application" >> help >> diff --git a/package/erlang/erlang.mk b/package/erlang/erlang.mk >> index 0b8619e..007053a 100644 >> --- a/package/erlang/erlang.mk >> +++ b/package/erlang/erlang.mk >> @@ -22,9 +22,11 @@ ERLANG_CONF_ENV += erl_xcomp_sysroot=$(STAGING_DIR) >> >> ERLANG_CONF_OPTS = --without-javac >> >> -ifeq ($(BR2_PACKAGE_LIBATOMIC_OPS),y) >> +ifeq ($(BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS),y) >> ERLANG_DEPENDENCIES += libatomic_ops >> ERLANG_CONF_OPTS += --with-libatomic_ops=$(STAGING_DIR)/usr >> +else >> +ERLANG_CONF_OPTS += --without-libatomic_ops >> endif > > So the consition for this block should stay the same, but the > --without-libatomic_ops addition is still welcome. > > Regards, > Yann E. MORIN. > >> # erlang uses openssl for all things crypto. Since the host tools (such as >> -- >> 1.9.1 >> >> _______________________________________________ >> buildroot mailing list >> buildroot@busybox.net >> http://lists.busybox.net/mailman/listinfo/buildroot > > -- > .-----------------.--------------------.------------------.--------------------. > | Yann E. MORIN | Real-Time Embedded | /"\ ASCII RIBBON | Erics' conspiracy: | > | +33 662 376 056 | Software Designer | \ / CAMPAIGN | ___ | > | +33 223 225 172 `------------.-------: X AGAINST | \e/ There is no | > | http://ymorin.is-a-geek.org/ | _/*\_ | / \ HTML MAIL | v conspiracy. | > '------------------------------^-------^------------------^--------------------'
Frank, All, On 2014-12-22 12:49 -0500, Frank Hunleth spake thusly: > On Mon, Dec 22, 2014 at 12:13 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote: > > Franck, All, > > > > On 2014-12-22 04:04 -0500, Frank Hunleth spake thusly: > >> Erlang can use either the system libatomic_ops or its own version. > >> However, if using the system version, it must find implementations for > >> AO_compare_and_swap() and other calls. Since these are not available on > >> all platforms, selectively enable the use of the system libatomic_ops. > >> > >> Fixes: > >> http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/ > >> http://autobuild.buildroot.net/results/c74/c743cfca629fb332bbb1327cf4ea360f0a4e4bfe/ > >> http://autobuild.buildroot.net/results/095/095348d4d309c2a408a3b297b4325348ed1dd7e8/ > >> > >> Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com> > >> --- > >> package/erlang/Config.in | 10 ++++++++++ > >> package/erlang/erlang.mk | 4 +++- > >> 2 files changed, 13 insertions(+), 1 deletion(-) > >> > >> diff --git a/package/erlang/Config.in b/package/erlang/Config.in > >> index 56830da..9caf1ec 100644 > >> --- a/package/erlang/Config.in > >> +++ b/package/erlang/Config.in > >> @@ -26,6 +26,16 @@ config BR2_PACKAGE_ERLANG_SMP > >> If you do not need SMP support, turning this option off reduces > >> compile time and the size of the Erlang installation. > >> > >> +config BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS > >> + bool > >> + select BR2_PACKAGE_LIBATOMIC_OPS > >> + default y if BR2_ARM_CPU_ARMV7A || BR2_x86_64 > > > > Well, we already have BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS that defines > > which architecture libatomic_ops supports. > > > > So, unless AO_compare_and_swap() is not available on all those > > architectures (and it seems it is), you should use that symbol instead. > > That was my first thought, but if you look at the configs for the > failed builds, BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS=y is defined. E.g.: > > http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/config > > Unfortunately, configure only prints the following to the build log so > it's not immediately obvious which function was missing: > > checking for a usable libatomic_ops implementation... no > configure: error: No usable libatomic_ops implementation found > > My assumption is that AO_compare_and_swap() is missing since that's > what I saw on a BR2_ARM_CPU_ARMV4 platform, but it could be something > else on BR2_ARM_CPU_ARMV5 (the config that I referenced above). Well, looking at output/build/erlang-17.4/erts/config.log, one can see: conftest.c:84:2: error: #error No compare_and_swap which is consistent with the corresponding check, that looks for some variant of AO_compare_and_swap. So you were right, it's AO_compare_and_swap that is missing. Let's see why... Any definition of AO_compare_and_swap is enclosed in a pre-processor block, conditional on AO_ARM_HAVE_LDREX. AO_ARM_HAVE_LDREX is defined for anything armv6+ (except armv6m which is thumb-only, but I doubt we have support for that, and that Linux even runs on that processor). So for ARM, we need armv6+ to use libatomic_ops. However, I fail to see the reasoning for singling-out armv7a (and armv6) and x86_64. Is there no other architecture that has AO_compare_and_swap() or any of its variants? What about armv8 (AArch64), i386, sparc and the others? Maybe we could add this instead: config BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS bool default y depends on BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS # On ARM, only armv6+ has the necessary AO_compare_and_swap() depends on BR2_ARM_CPU_ARMV6 || BR2_ARM_CPU_ARMV7A || !(BR2_arm || BR2_armeb) help Use the system libatomic_ops on platforms that provide implementations for AO_store(), AO_load(), and AO_compare_and_swap(). Platforms without support for those functions must still use the Erlang-provided implementation. > >> config BR2_PACKAGE_ERLANG_MEGACO > >> bool "install megaco application" > >> help > >> diff --git a/package/erlang/erlang.mk b/package/erlang/erlang.mk > >> index 0b8619e..007053a 100644 > >> --- a/package/erlang/erlang.mk > >> +++ b/package/erlang/erlang.mk > >> @@ -22,9 +22,11 @@ ERLANG_CONF_ENV += erl_xcomp_sysroot=$(STAGING_DIR) > >> > >> ERLANG_CONF_OPTS = --without-javac > >> > >> -ifeq ($(BR2_PACKAGE_LIBATOMIC_OPS),y) > >> +ifeq ($(BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS),y) > >> ERLANG_DEPENDENCIES += libatomic_ops > >> ERLANG_CONF_OPTS += --with-libatomic_ops=$(STAGING_DIR)/usr > >> +else > >> +ERLANG_CONF_OPTS += --without-libatomic_ops It would also be good to add a comment that says something like: # --without-libatomic_ops means: do not use an external libatomic_ops; # atomic operations use an internal implementation instead. Regards, Yann E. MORIN.
Yann, On Mon, Dec 22, 2014 at 4:24 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote: > Frank, All, > > On 2014-12-22 12:49 -0500, Frank Hunleth spake thusly: >> On Mon, Dec 22, 2014 at 12:13 PM, Yann E. MORIN <yann.morin.1998@free.fr> wrote: >> > Franck, All, >> > >> > On 2014-12-22 04:04 -0500, Frank Hunleth spake thusly: >> >> Erlang can use either the system libatomic_ops or its own version. >> >> However, if using the system version, it must find implementations for >> >> AO_compare_and_swap() and other calls. Since these are not available on >> >> all platforms, selectively enable the use of the system libatomic_ops. >> >> >> >> Fixes: >> >> http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/ >> >> http://autobuild.buildroot.net/results/c74/c743cfca629fb332bbb1327cf4ea360f0a4e4bfe/ >> >> http://autobuild.buildroot.net/results/095/095348d4d309c2a408a3b297b4325348ed1dd7e8/ >> >> >> >> Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com> >> >> --- >> >> package/erlang/Config.in | 10 ++++++++++ >> >> package/erlang/erlang.mk | 4 +++- >> >> 2 files changed, 13 insertions(+), 1 deletion(-) >> >> >> >> diff --git a/package/erlang/Config.in b/package/erlang/Config.in >> >> index 56830da..9caf1ec 100644 >> >> --- a/package/erlang/Config.in >> >> +++ b/package/erlang/Config.in >> >> @@ -26,6 +26,16 @@ config BR2_PACKAGE_ERLANG_SMP >> >> If you do not need SMP support, turning this option off reduces >> >> compile time and the size of the Erlang installation. >> >> >> >> +config BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS >> >> + bool >> >> + select BR2_PACKAGE_LIBATOMIC_OPS >> >> + default y if BR2_ARM_CPU_ARMV7A || BR2_x86_64 >> > >> > Well, we already have BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS that defines >> > which architecture libatomic_ops supports. >> > >> > So, unless AO_compare_and_swap() is not available on all those >> > architectures (and it seems it is), you should use that symbol instead. >> >> That was my first thought, but if you look at the configs for the >> failed builds, BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS=y is defined. E.g.: >> >> http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/config >> >> Unfortunately, configure only prints the following to the build log so >> it's not immediately obvious which function was missing: >> >> checking for a usable libatomic_ops implementation... no >> configure: error: No usable libatomic_ops implementation found >> >> My assumption is that AO_compare_and_swap() is missing since that's >> what I saw on a BR2_ARM_CPU_ARMV4 platform, but it could be something >> else on BR2_ARM_CPU_ARMV5 (the config that I referenced above). > > Well, looking at output/build/erlang-17.4/erts/config.log, one can see: > conftest.c:84:2: error: #error No compare_and_swap > > which is consistent with the corresponding check, that looks for some > variant of AO_compare_and_swap. > > So you were right, it's AO_compare_and_swap that is missing. > > Let's see why... > > Any definition of AO_compare_and_swap is enclosed in a pre-processor > block, conditional on AO_ARM_HAVE_LDREX. > > AO_ARM_HAVE_LDREX is defined for anything armv6+ (except armv6m which is > thumb-only, but I doubt we have support for that, and that Linux even > runs on that processor). > > So for ARM, we need armv6+ to use libatomic_ops. > > However, I fail to see the reasoning for singling-out armv7a (and armv6) > and x86_64. Is there no other architecture that has AO_compare_and_swap() > or any of its variants? What about armv8 (AArch64), i386, sparc and the > others? > > Maybe we could add this instead: > > config BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS > bool > default y > depends on BR2_PACKAGE_LIBATOMIC_ARCH_SUPPORTS > # On ARM, only armv6+ has the necessary AO_compare_and_swap() > depends on BR2_ARM_CPU_ARMV6 || BR2_ARM_CPU_ARMV7A || !(BR2_arm || BR2_armeb) > help > Use the system libatomic_ops on platforms that provide > implementations for AO_store(), AO_load(), and AO_compare_and_swap(). > Platforms without support for those functions must still use the > Erlang-provided implementation. > Completely agree. I've updated the patch. Thanks for investigating more into which systems should have an AO_compare_and_swap() implementation. >> >> config BR2_PACKAGE_ERLANG_MEGACO >> >> bool "install megaco application" >> >> help >> >> diff --git a/package/erlang/erlang.mk b/package/erlang/erlang.mk >> >> index 0b8619e..007053a 100644 >> >> --- a/package/erlang/erlang.mk >> >> +++ b/package/erlang/erlang.mk >> >> @@ -22,9 +22,11 @@ ERLANG_CONF_ENV += erl_xcomp_sysroot=$(STAGING_DIR) >> >> >> >> ERLANG_CONF_OPTS = --without-javac >> >> >> >> -ifeq ($(BR2_PACKAGE_LIBATOMIC_OPS),y) >> >> +ifeq ($(BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS),y) >> >> ERLANG_DEPENDENCIES += libatomic_ops >> >> ERLANG_CONF_OPTS += --with-libatomic_ops=$(STAGING_DIR)/usr >> >> +else >> >> +ERLANG_CONF_OPTS += --without-libatomic_ops > > It would also be good to add a comment that says something like: > > # --without-libatomic_ops means: do not use an external libatomic_ops; > # atomic operations use an internal implementation instead. Done. Thank you very much for spending time looking into the patch. Frank
diff --git a/package/erlang/Config.in b/package/erlang/Config.in index 56830da..9caf1ec 100644 --- a/package/erlang/Config.in +++ b/package/erlang/Config.in @@ -26,6 +26,16 @@ config BR2_PACKAGE_ERLANG_SMP If you do not need SMP support, turning this option off reduces compile time and the size of the Erlang installation. +config BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS + bool + select BR2_PACKAGE_LIBATOMIC_OPS + default y if BR2_ARM_CPU_ARMV7A || BR2_x86_64 + help + Use the system libatomic_ops on platforms that provide + implementations for AO_store(), AO_load(), and AO_compare_and_swap(). + Platforms without support for those functions must still use the + Erlang-provided implementation. + config BR2_PACKAGE_ERLANG_MEGACO bool "install megaco application" help diff --git a/package/erlang/erlang.mk b/package/erlang/erlang.mk index 0b8619e..007053a 100644 --- a/package/erlang/erlang.mk +++ b/package/erlang/erlang.mk @@ -22,9 +22,11 @@ ERLANG_CONF_ENV += erl_xcomp_sysroot=$(STAGING_DIR) ERLANG_CONF_OPTS = --without-javac -ifeq ($(BR2_PACKAGE_LIBATOMIC_OPS),y) +ifeq ($(BR2_PACKAGE_ERLANG_USE_LIBATOMIC_OPS),y) ERLANG_DEPENDENCIES += libatomic_ops ERLANG_CONF_OPTS += --with-libatomic_ops=$(STAGING_DIR)/usr +else +ERLANG_CONF_OPTS += --without-libatomic_ops endif # erlang uses openssl for all things crypto. Since the host tools (such as
Erlang can use either the system libatomic_ops or its own version. However, if using the system version, it must find implementations for AO_compare_and_swap() and other calls. Since these are not available on all platforms, selectively enable the use of the system libatomic_ops. Fixes: http://autobuild.buildroot.net/results/eba/eba5bf85e9ff98916cd3638b5f13ab5bd54564d8/ http://autobuild.buildroot.net/results/c74/c743cfca629fb332bbb1327cf4ea360f0a4e4bfe/ http://autobuild.buildroot.net/results/095/095348d4d309c2a408a3b297b4325348ed1dd7e8/ Signed-off-by: Frank Hunleth <fhunleth@troodon-software.com> --- package/erlang/Config.in | 10 ++++++++++ package/erlang/erlang.mk | 4 +++- 2 files changed, 13 insertions(+), 1 deletion(-)