| Message ID | 20210418183658.1675843-1-glex.spb@gmail.com |
|---|---|
| State | Rejected |
| Headers | show |
| Series | [1/1] package/valgrind: Add a setting for LTO build | expand |
Hello Gleb, On Sun, 18 Apr 2021 19:36:58 +0100, Gleb Mazovetskiy <glex.spb@gmail.com> wrote: > Valgrind LTO build takes over an hour on my Ryzen 3950x. > Can confirm a build time increase (AMD Ryzen 7 1800X): - without LTO: real 0m54,741s user 3m29,941s sys 0m10,949s - with LTO: real 5m48,009s user 6m23,040s sys 0m13,197s > This is not always worth it for the ~10% size reduction and a small > performance improvement it offers (see https://www.valgrind.org/docs/manual/dist.news.html) > > Adds a new `BR2_VALGRIND_ENABLE_LTO` setting to control LTO enablement > for Valgrind separately from the global BR2_GCC_ENABLE_LTO setting. > > Signed-off-by: Gleb Mazovetskiy <glex.spb@gmail.com> > --- > package/valgrind/Config.in | 10 ++++++++++ > package/valgrind/valgrind.mk | 2 +- > 2 files changed, 11 insertions(+), 1 deletion(-) > > diff --git a/package/valgrind/Config.in b/package/valgrind/Config.in > index 56e4af21fa..eff54e7949 100644 > --- a/package/valgrind/Config.in > +++ b/package/valgrind/Config.in > @@ -84,4 +84,14 @@ config BR2_PACKAGE_VALGRIND_NULGRIND > help > This option allows to install the Nulgrind tool > > +if BR2_GCC_ENABLE_LTO > + > +config BR2_VALGRIND_ENABLE_LTO > + bool "Build Valgrind with link-time optimization" > + help > + This produces a faster / smaller valgrind (up to 10%) at the cost > + of massively increased build time (can be over an hour). Be careful with absolute times, depends strongly on the used hardware... (out of interest, what is your baseline compile time?)... Would move this section up-to/before the tools selection section... Regards, Peter > + > +endif > + > endif > diff --git a/package/valgrind/valgrind.mk b/package/valgrind/valgrind.mk > index b87e1e518f..07fb1f7d42 100644 > --- a/package/valgrind/valgrind.mk > +++ b/package/valgrind/valgrind.mk > @@ -50,7 +50,7 @@ VALGRIND_CONF_OPTS += \ > --host=$(patsubst arm-%,armv7-%,$(GNU_TARGET_NAME)) > endif > > -ifeq ($(BR2_GCC_ENABLE_LTO),y) > +ifeq ($(BR2_VALGRIND_ENABLE_LTO),y) > VALGRIND_CONF_OPTS += --enable-lto > else > VALGRIND_CONF_OPTS += --disable-lto
By the way, I should've mentioned that it's over 1 hour for MIPS32R2 with uclibc On Sun, Apr 18, 2021 at 10:59 PM Peter Seiderer <ps.report@gmx.net> wrote: > Hello Gleb, > On Sun, 18 Apr 2021 19:36:58 +0100, Gleb Mazovetskiy <glex.spb@gmail.com> > wrote: > > > Valgrind LTO build takes over an hour on my Ryzen 3950x. > > > > Can confirm a build time increase (AMD Ryzen 7 1800X): > > - without LTO: > > real 0m54,741s > user 3m29,941s > sys 0m10,949s > > - with LTO: > > real 5m48,009s > user 6m23,040s > sys 0m13,197s > > > This is not always worth it for the ~10% size reduction and a small > > performance improvement it offers (see > https://www.valgrind.org/docs/manual/dist.news.html) > > > > Adds a new `BR2_VALGRIND_ENABLE_LTO` setting to control LTO enablement > > for Valgrind separately from the global BR2_GCC_ENABLE_LTO setting. > > > > Signed-off-by: Gleb Mazovetskiy <glex.spb@gmail.com> > > --- > > package/valgrind/Config.in | 10 ++++++++++ > > package/valgrind/valgrind.mk | 2 +- > > 2 files changed, 11 insertions(+), 1 deletion(-) > > > > diff --git a/package/valgrind/Config.in b/package/valgrind/Config.in > > index 56e4af21fa..eff54e7949 100644 > > --- a/package/valgrind/Config.in > > +++ b/package/valgrind/Config.in > > @@ -84,4 +84,14 @@ config BR2_PACKAGE_VALGRIND_NULGRIND > > help > > This option allows to install the Nulgrind tool > > > > +if BR2_GCC_ENABLE_LTO > > + > > +config BR2_VALGRIND_ENABLE_LTO > > + bool "Build Valgrind with link-time optimization" > > + help > > + This produces a faster / smaller valgrind (up to 10%) at the cost > > + of massively increased build time (can be over an hour). > > Be careful with absolute times, depends strongly on the used hardware... > (out of interest, what is your baseline compile time?)... > > Would move this section up-to/before the tools selection section... > > Regards, > Peter > > > + > > +endif > > + > > endif > > diff --git a/package/valgrind/valgrind.mk b/package/valgrind/valgrind.mk > > index b87e1e518f..07fb1f7d42 100644 > > --- a/package/valgrind/valgrind.mk > > +++ b/package/valgrind/valgrind.mk > > @@ -50,7 +50,7 @@ VALGRIND_CONF_OPTS += \ > > --host=$(patsubst arm-%,armv7-%,$(GNU_TARGET_NAME)) > > endif > > > > -ifeq ($(BR2_GCC_ENABLE_LTO),y) > > +ifeq ($(BR2_VALGRIND_ENABLE_LTO),y) > > VALGRIND_CONF_OPTS += --enable-lto > > else > > VALGRIND_CONF_OPTS += --disable-lto > >
On 18/04/2021 23:59, Peter Seiderer wrote: > Hello Gleb, > On Sun, 18 Apr 2021 19:36:58 +0100, Gleb Mazovetskiy <glex.spb@gmail.com> wrote: > >> Valgrind LTO build takes over an hour on my Ryzen 3950x. >> > > Can confirm a build time increase (AMD Ryzen 7 1800X): > > - without LTO: > > real 0m54,741s > user 3m29,941s > sys 0m10,949s > > - with LTO: > > real 5m48,009s > user 6m23,040s > sys 0m13,197s > >> This is not always worth it for the ~10% size reduction and a small >> performance improvement it offers (see https://www.valgrind.org/docs/manual/dist.news.html) >> >> Adds a new `BR2_VALGRIND_ENABLE_LTO` setting to control LTO enablement >> for Valgrind separately from the global BR2_GCC_ENABLE_LTO setting. Adding per-package options to enable debug and optimisation features is really not the way to go. Instead what I've done is to create a series [1] that turns the LTO option in a global option, that clearly explains in the help text that it may have a big impact on build time. I've removed the BR2_GCC_ENABLE_LTO option entirely because it was not actually doing what it advertises. Let me know what you think. I've marked this patch as Rejected. Regards, Arnout [1] https://patchwork.ozlabs.org/project/buildroot/list/?series=311175 >> >> Signed-off-by: Gleb Mazovetskiy <glex.spb@gmail.com> >> --- >> package/valgrind/Config.in | 10 ++++++++++ >> package/valgrind/valgrind.mk | 2 +- >> 2 files changed, 11 insertions(+), 1 deletion(-) >> >> diff --git a/package/valgrind/Config.in b/package/valgrind/Config.in >> index 56e4af21fa..eff54e7949 100644 >> --- a/package/valgrind/Config.in >> +++ b/package/valgrind/Config.in >> @@ -84,4 +84,14 @@ config BR2_PACKAGE_VALGRIND_NULGRIND >> help >> This option allows to install the Nulgrind tool >> >> +if BR2_GCC_ENABLE_LTO >> + >> +config BR2_VALGRIND_ENABLE_LTO >> + bool "Build Valgrind with link-time optimization" >> + help >> + This produces a faster / smaller valgrind (up to 10%) at the cost >> + of massively increased build time (can be over an hour). > > Be careful with absolute times, depends strongly on the used hardware... > (out of interest, what is your baseline compile time?)... > > Would move this section up-to/before the tools selection section... > > Regards, > Peter > >> + >> +endif >> + >> endif >> diff --git a/package/valgrind/valgrind.mk b/package/valgrind/valgrind.mk >> index b87e1e518f..07fb1f7d42 100644 >> --- a/package/valgrind/valgrind.mk >> +++ b/package/valgrind/valgrind.mk >> @@ -50,7 +50,7 @@ VALGRIND_CONF_OPTS += \ >> --host=$(patsubst arm-%,armv7-%,$(GNU_TARGET_NAME)) >> endif >> >> -ifeq ($(BR2_GCC_ENABLE_LTO),y) >> +ifeq ($(BR2_VALGRIND_ENABLE_LTO),y) >> VALGRIND_CONF_OPTS += --enable-lto >> else >> VALGRIND_CONF_OPTS += --disable-lto > > _______________________________________________ > buildroot mailing list > buildroot@busybox.net > http://lists.busybox.net/mailman/listinfo/buildroot
We don't want to disable LTO globally only for certain packages We want LTO generally but not for a development tool that takes over 1 hour to build with LTO vs 1 minute without it. Is it possible to do it on a per-package basis? By the way, it would also be useful to control BR2_STATIC_LIBS on a per-package basis (recent example: https://patchwork.ozlabs.org/project/buildroot/patch/20220620115510.33792-1-paul@crapouillou.net/ ) On Mon, Jul 25, 2022 at 4:27 PM Arnout Vandecappelle <arnout@mind.be> wrote: > > > On 18/04/2021 23:59, Peter Seiderer wrote: > > Hello Gleb, > > On Sun, 18 Apr 2021 19:36:58 +0100, Gleb Mazovetskiy <glex.spb@gmail.com> > wrote: > > > >> Valgrind LTO build takes over an hour on my Ryzen 3950x. > >> > > > > Can confirm a build time increase (AMD Ryzen 7 1800X): > > > > - without LTO: > > > > real 0m54,741s > > user 3m29,941s > > sys 0m10,949s > > > > - with LTO: > > > > real 5m48,009s > > user 6m23,040s > > sys 0m13,197s > > > >> This is not always worth it for the ~10% size reduction and a small > >> performance improvement it offers (see > https://www.valgrind.org/docs/manual/dist.news.html) > >> > >> Adds a new `BR2_VALGRIND_ENABLE_LTO` setting to control LTO enablement > >> for Valgrind separately from the global BR2_GCC_ENABLE_LTO setting. > > Adding per-package options to enable debug and optimisation features is > really > not the way to go. > > Instead what I've done is to create a series [1] that turns the LTO > option in > a global option, that clearly explains in the help text that it may have a > big > impact on build time. I've removed the BR2_GCC_ENABLE_LTO option entirely > because it was not actually doing what it advertises. > > Let me know what you think. > > I've marked this patch as Rejected. > > Regards, > Arnout > > [1] https://patchwork.ozlabs.org/project/buildroot/list/?series=311175 > > >> > >> Signed-off-by: Gleb Mazovetskiy <glex.spb@gmail.com> > >> --- > >> package/valgrind/Config.in | 10 ++++++++++ > >> package/valgrind/valgrind.mk | 2 +- > >> 2 files changed, 11 insertions(+), 1 deletion(-) > >> > >> diff --git a/package/valgrind/Config.in b/package/valgrind/Config.in > >> index 56e4af21fa..eff54e7949 100644 > >> --- a/package/valgrind/Config.in > >> +++ b/package/valgrind/Config.in > >> @@ -84,4 +84,14 @@ config BR2_PACKAGE_VALGRIND_NULGRIND > >> help > >> This option allows to install the Nulgrind tool > >> > >> +if BR2_GCC_ENABLE_LTO > >> + > >> +config BR2_VALGRIND_ENABLE_LTO > >> + bool "Build Valgrind with link-time optimization" > >> + help > >> + This produces a faster / smaller valgrind (up to 10%) at the cost > >> + of massively increased build time (can be over an hour). > > > > Be careful with absolute times, depends strongly on the used hardware... > > (out of interest, what is your baseline compile time?)... > > > > Would move this section up-to/before the tools selection section... > > > > Regards, > > Peter > > > >> + > >> +endif > >> + > >> endif > >> diff --git a/package/valgrind/valgrind.mk b/package/valgrind/ > valgrind.mk > >> index b87e1e518f..07fb1f7d42 100644 > >> --- a/package/valgrind/valgrind.mk > >> +++ b/package/valgrind/valgrind.mk > >> @@ -50,7 +50,7 @@ VALGRIND_CONF_OPTS += \ > >> --host=$(patsubst arm-%,armv7-%,$(GNU_TARGET_NAME)) > >> endif > >> > >> -ifeq ($(BR2_GCC_ENABLE_LTO),y) > >> +ifeq ($(BR2_VALGRIND_ENABLE_LTO),y) > >> VALGRIND_CONF_OPTS += --enable-lto > >> else > >> VALGRIND_CONF_OPTS += --disable-lto > > > > _______________________________________________ > > buildroot mailing list > > buildroot@busybox.net > > http://lists.busybox.net/mailman/listinfo/buildroot >
diff --git a/package/valgrind/Config.in b/package/valgrind/Config.in index 56e4af21fa..eff54e7949 100644 --- a/package/valgrind/Config.in +++ b/package/valgrind/Config.in @@ -84,4 +84,14 @@ config BR2_PACKAGE_VALGRIND_NULGRIND help This option allows to install the Nulgrind tool +if BR2_GCC_ENABLE_LTO + +config BR2_VALGRIND_ENABLE_LTO + bool "Build Valgrind with link-time optimization" + help + This produces a faster / smaller valgrind (up to 10%) at the cost + of massively increased build time (can be over an hour). + +endif + endif diff --git a/package/valgrind/valgrind.mk b/package/valgrind/valgrind.mk index b87e1e518f..07fb1f7d42 100644 --- a/package/valgrind/valgrind.mk +++ b/package/valgrind/valgrind.mk @@ -50,7 +50,7 @@ VALGRIND_CONF_OPTS += \ --host=$(patsubst arm-%,armv7-%,$(GNU_TARGET_NAME)) endif -ifeq ($(BR2_GCC_ENABLE_LTO),y) +ifeq ($(BR2_VALGRIND_ENABLE_LTO),y) VALGRIND_CONF_OPTS += --enable-lto else VALGRIND_CONF_OPTS += --disable-lto
Valgrind LTO build takes over an hour on my Ryzen 3950x. This is not always worth it for the ~10% size reduction and a small performance improvement it offers (see https://www.valgrind.org/docs/manual/dist.news.html) Adds a new `BR2_VALGRIND_ENABLE_LTO` setting to control LTO enablement for Valgrind separately from the global BR2_GCC_ENABLE_LTO setting. Signed-off-by: Gleb Mazovetskiy <glex.spb@gmail.com> --- package/valgrind/Config.in | 10 ++++++++++ package/valgrind/valgrind.mk | 2 +- 2 files changed, 11 insertions(+), 1 deletion(-)