[PATCH u-boot v2.1 38/38] ARM: enable LTO for some boards

Tom Rini trini at konsulko.com
Fri Mar 12 21:47:12 CET 2021 

On Fri, Mar 12, 2021 at 06:36:05PM +0100, Marek Behun wrote:
> On Fri, 12 Mar 2021 18:19:08 +0100
> Heinrich Schuchardt <xypron.glpk at gmx.de> wrote:
> 
> > On 12.03.21 18:03, Marek Behun wrote:
> > > On Fri, 12 Mar 2021 08:34:41 -0800
> > > Tim Harvey <tharvey at gateworks.com> wrote:
> > >  
> > >> On Fri, Mar 12, 2021 at 5:47 AM Marek Behún <marek.behun at nic.cz> wrote:  
> > >>>
> > >>> Enable LTO for some boards that were tested by people on U-Boot Mailing
> > >>> List.
> > >>>
> > >>> Signed-off-by: Marek Behún <marek.behun at nic.cz>
> > >>> Tested-by: Adam Ford <aford173 at gmail.com>
> > >>> Tested-by: Pali Rohár <pali at kernel.org>
> > >>> Tested-by: Tim Harvey <tharvey at gateworks.com>
> > >>> ---
> > >>>  configs/am3517_evm_defconfig          | 1 +
> > >>>  configs/da850evm_defconfig            | 1 +
> > >>>  configs/da850evm_direct_nor_defconfig | 1 +
> > >>>  configs/da850evm_nand_defconfig       | 1 +
> > >>>  configs/imx6q_logic_defconfig         | 1 +
> > >>>  configs/imx8mm_beacon_defconfig       | 1 +
> > >>>  configs/imx8mm_venice_defconfig       | 1 +
> > >>>  configs/imx8mn_beacon_2g_defconfig    | 1 +
> > >>>  configs/imx8mn_beacon_defconfig       | 1 +
> > >>>  configs/nokia_rx51_defconfig          | 1 +
> > >>>  configs/omap3_logic_defconfig         | 1 +
> > >>>  configs/r8a774a1_beacon_defconfig     | 1 +
> > >>>  configs/r8a774b1_beacon_defconfig     | 1 +
> > >>>  configs/r8a774e1_beacon_defconfig     | 1 +
> > >>>  configs/turris_mox_defconfig          | 1 +
> > >>>  configs/turris_omnia_defconfig        | 1 +
> > >>>  16 files changed, 16 insertions(+)
> > >>>
> > >>> diff --git a/configs/am3517_evm_defconfig b/configs/am3517_evm_defconfig
> > >>> index bae0e0af35..d61eec94a4 100644
> > >>> --- a/configs/am3517_evm_defconfig
> > >>> +++ b/configs/am3517_evm_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  # CONFIG_SPL_USE_ARCH_MEMCPY is not set
> > >>>  # CONFIG_SPL_USE_ARCH_MEMSET is not set
> > >>> diff --git a/configs/da850evm_defconfig b/configs/da850evm_defconfig
> > >>> index 26e76a2929..6ff5e21bc6 100644
> > >>> --- a/configs/da850evm_defconfig
> > >>> +++ b/configs/da850evm_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_SYS_THUMB_BUILD=y
> > >>>  CONFIG_ARCH_DAVINCI=y
> > >>> diff --git a/configs/da850evm_direct_nor_defconfig b/configs/da850evm_direct_nor_defconfig
> > >>> index d3860a963d..06c7ce7c47 100644
> > >>> --- a/configs/da850evm_direct_nor_defconfig
> > >>> +++ b/configs/da850evm_direct_nor_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_CPU_INIT=y
> > >>>  CONFIG_ARCH_DAVINCI=y
> > >>> diff --git a/configs/da850evm_nand_defconfig b/configs/da850evm_nand_defconfig
> > >>> index 0d0e9a148d..be737564e1 100644
> > >>> --- a/configs/da850evm_nand_defconfig
> > >>> +++ b/configs/da850evm_nand_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_SYS_THUMB_BUILD=y
> > >>>  CONFIG_ARCH_DAVINCI=y
> > >>> diff --git a/configs/imx6q_logic_defconfig b/configs/imx6q_logic_defconfig
> > >>> index 36dc24d080..0f8aea6983 100644
> > >>> --- a/configs/imx6q_logic_defconfig
> > >>> +++ b/configs/imx6q_logic_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_MX6=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x17800000
> > >>> diff --git a/configs/imx8mm_beacon_defconfig b/configs/imx8mm_beacon_defconfig
> > >>> index 045b19f4f3..e8bb44eea6 100644
> > >>> --- a/configs/imx8mm_beacon_defconfig
> > >>> +++ b/configs/imx8mm_beacon_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_IMX8M=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x40200000
> > >>> diff --git a/configs/imx8mm_venice_defconfig b/configs/imx8mm_venice_defconfig
> > >>> index a15c3641f6..dff8f64540 100644
> > >>> --- a/configs/imx8mm_venice_defconfig
> > >>> +++ b/configs/imx8mm_venice_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_IMX8M=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x40200000
> > >>> diff --git a/configs/imx8mn_beacon_2g_defconfig b/configs/imx8mn_beacon_2g_defconfig
> > >>> index 58b8e49486..1c8cbc2c89 100644
> > >>> --- a/configs/imx8mn_beacon_2g_defconfig
> > >>> +++ b/configs/imx8mn_beacon_2g_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_IMX8M=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x40200000
> > >>> diff --git a/configs/imx8mn_beacon_defconfig b/configs/imx8mn_beacon_defconfig
> > >>> index d6a3385d8d..6457b9409a 100644
> > >>> --- a/configs/imx8mn_beacon_defconfig
> > >>> +++ b/configs/imx8mn_beacon_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_IMX8M=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x40200000
> > >>> diff --git a/configs/nokia_rx51_defconfig b/configs/nokia_rx51_defconfig
> > >>> index 312ca3a1a9..85ca627790 100644
> > >>> --- a/configs/nokia_rx51_defconfig
> > >>> +++ b/configs/nokia_rx51_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  # CONFIG_SYS_THUMB_BUILD is not set
> > >>>  CONFIG_ARCH_OMAP2PLUS=y
> > >>> diff --git a/configs/omap3_logic_defconfig b/configs/omap3_logic_defconfig
> > >>> index 4e37237b86..cc4b727a2c 100644
> > >>> --- a/configs/omap3_logic_defconfig
> > >>> +++ b/configs/omap3_logic_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  # CONFIG_SPL_USE_ARCH_MEMCPY is not set
> > >>>  # CONFIG_SPL_USE_ARCH_MEMSET is not set
> > >>> diff --git a/configs/r8a774a1_beacon_defconfig b/configs/r8a774a1_beacon_defconfig
> > >>> index 2f45edd92e..9dd5d9192e 100644
> > >>> --- a/configs/r8a774a1_beacon_defconfig
> > >>> +++ b/configs/r8a774a1_beacon_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_RMOBILE=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x50000000
> > >>> diff --git a/configs/r8a774b1_beacon_defconfig b/configs/r8a774b1_beacon_defconfig
> > >>> index ca514bb1aa..b7d7f23f5a 100644
> > >>> --- a/configs/r8a774b1_beacon_defconfig
> > >>> +++ b/configs/r8a774b1_beacon_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_RMOBILE=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x50000000
> > >>> diff --git a/configs/r8a774e1_beacon_defconfig b/configs/r8a774e1_beacon_defconfig
> > >>> index b89729d92a..3e44edf29f 100644
> > >>> --- a/configs/r8a774e1_beacon_defconfig
> > >>> +++ b/configs/r8a774e1_beacon_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_RMOBILE=y
> > >>>  CONFIG_SYS_TEXT_BASE=0x50000000
> > >>> diff --git a/configs/turris_mox_defconfig b/configs/turris_mox_defconfig
> > >>> index f938fbb475..2a351d9180 100644
> > >>> --- a/configs/turris_mox_defconfig
> > >>> +++ b/configs/turris_mox_defconfig
> > >>> @@ -1,3 +1,4 @@
> > >>> +CONFIG_LTO=y
> > >>>  CONFIG_ARM=y
> > >>>  CONFIG_ARCH_CPU_INIT=y
> > >>>  CONFIG_ARCH_MVEBU=y
> > >>> diff --git a/configs/turris_omnia_defconfig b/configs/turris_omnia_defconfig
> > >>> index 4b8843d7be..d7a2ec3592 100644
> > >>> --- a/configs/turris_omnia_defconfig
> > >>> +++ b/configs/turris_omnia_defconfig
> > >>> @@ -1,3 +1,4 @@  
> > >>> +CONFIG_LTO=y>>>  CONFIG_ARM=y  
> > >>>  CONFIG_ARCH_CPU_INIT=y
> > >>>  CONFIG_SPL_SYS_THUMB_BUILD=y
> > >>> --
> > >>> 2.26.2
> > >>>  
> > >>
> > >> Marek,
> > >>
> > >> Perhaps I didn't test the property test before as I did not realize
> > >> there was a config to be enabled.
> > >>
> > >> Enabling CONFIG_LTO breaks linking the SPL (linking uboot is fine):
> > >>   LTO     spl/u-boot-spl
> > >> make[2]: *** read jobs pipe: No such file or directory.  Stop.
> > >> make[2]: *** Waiting for unfinished jobs....
> > >> lto-wrapper: fatal error: make returned 2 exit status
> > >> compilation terminated.
> > >> /usr/src/venice/buildroot/output/host/lib/gcc/aarch64-buildroot-linux-gnu/9.3.0/../../../../aarch64-buildroot-linux-gnu/bin/ld:
> > >> error: lto-wrapper failed
> > >> collect2: error: ld returned 1 exit status
> > >> scripts/Makefile.spl:461: recipe for target 'spl/u-boot-spl' failed
> > >> make[1]: *** [spl/u-boot-spl] Error 1
> > >> Makefile:1985: recipe for target 'spl/u-boot-spl' failed
> > >> make: *** [spl/u-boot-spl] Error 2
> > >>
> > >> I'm using your lto branch
> > >>
> > >> Best Regards,
> > >>
> > >> Tim  
> > >
> > > Tim, try compiling with only one job, i.e.
> > >   make -j1
> > >  
> > 
> > If parallel build fails, we have a bug in the Makefile. It worked fine
> > without the LTO patches.
> 
> It may be a problem with GNU make's jobserver. Tom mentioned that
> there is a known race condition or something...

I was unclear at the time, sorry.  Yes, it sounds like there's some race
condition these patches are adding that needs to be addressed.  By the
nature of race condition they aren't always easy to trigger, but we
can't just ignore them if CI doesn't trip on it every time.

> If only there was a simple way to discover inside the Makefile the
> number of jobs given to the make command via the -j parameter, we could
> use -flto=$(JOBS).
> 
> I found this
> https://blog.jgc.org/2015/03/gnu-make-insanity-finding-value-of-j.html

Well, how is this being done in the Linux kernel?  Or maybe, sigh, this
isn't a problem with Clang's LTO which is what is in mainline Linux
kernel atm.  Maybe
https://lore.kernel.org/patchwork/project/lkml/list/?series=463749&state=*
will have some clues, all the same.

-- 
Tom
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