After glibc-2.36.9000-435-g569cfcc6bf commit 569cfcc6bf35c28112ca8d7112e9eb4a22bed5b8 Author: Samuel Thibault samuel.thibault@ens-lyon.org

hurd: Fix _NOFLSH value

the following benchmarks slowed down by more than 3%: - 459.GemsFDTD failed to build - 436.cactusADM failed to build

Below reproducer instructions can be used to re-build both "first_bad" and "last_good" cross-toolchains used in this bisection. Naturally, the scripts will fail when triggerring benchmarking jobs if you don't have access to Linaro TCWG CI.

For your convenience, we have uploaded tarballs with pre-processed source and assembly files at: - First_bad save-temps: $FIRST_BAD_ARTIFACTS/save-temps/ - Last_good save-temps: $LAST_GOOD_ARTIFACTS/save-temps/ - Baseline save-temps: $BASELINE_ARTIFACTS/save-temps/

Configuration: - Benchmark: SPEC CPU2006 - Toolchain: GCC + Glibc + GNU Linker - Version: all components were built from their tip of trunk - Target: aarch64-linux-gnu - Compiler flags: -O3 -flto - Hardware:

This benchmarking CI is work-in-progress, and we welcome feedback and suggestions at linaro-toolchain@lists.linaro.org . In our improvement plans is to add support for SPEC CPU2017 benchmarks and provide "perf report/annotate" data behind these reports.

THIS IS THE END OF INTERESTING STUFF. BELOW ARE LINKS TO BUILDS, REPRODUCTION INSTRUCTIONS, AND THE RAW COMMIT.

For latest status see comments in https://linaro.atlassian.net/browse/GNU-692 . Status of glibc-2.36.9000-435-g569cfcc6bf commit for tcwg_bmk-code_speed-spec2k6: commit 569cfcc6bf35c28112ca8d7112e9eb4a22bed5b8 Author: Samuel Thibault samuel.thibault@ens-lyon.org Date: Sun Jan 15 20:54:42 2023 +0100

hurd: Fix _NOFLSH value

shifting 1 (thus an integer) left 31 bit is undefined behavior. We have to make it an unsigned integer to properly get 0x80000000 (like done in other places). * gnu-aarch64-master-O3_LTO ** After glibc-2.36.9000-435-g569cfcc6bf commit 569cfcc6bf35c28112ca8d7112e9eb4a22bed5b8 ** Author: Samuel Thibault samuel.thibault@ens-lyon.org ** ** hurd: Fix _NOFLSH value ** ** the following benchmarks slowed down by more than 3%: ** - 459.GemsFDTD failed to build ** - 436.cactusADM failed to build ** https://ci.linaro.org/job/tcwg_bmk-code_speed-spec2k6-gnu-aarch64-master-O3_...

Bad build: https://ci.linaro.org/job/tcwg_bmk-code_speed-spec2k6-gnu-aarch64-master-O3_... Good build: https://ci.linaro.org/job/tcwg_bmk-code_speed-spec2k6-gnu-aarch64-master-O3_...

Reproduce current build: <cut> mkdir -p investigate-glibc-569cfcc6bf35c28112ca8d7112e9eb4a22bed5b8 cd investigate-glibc-569cfcc6bf35c28112ca8d7112e9eb4a22bed5b8

# Fetch scripts git clone https://git.linaro.org/toolchain/jenkins-scripts

# Fetch manifests for bad and good builds mkdir -p bad/artifacts good/artifacts curl -o bad/artifacts/manifest.sh https://ci.linaro.org/job/tcwg_bmk-code_speed-spec2k6-gnu-aarch64-master-O3_... --fail curl -o good/artifacts/manifest.sh https://ci.linaro.org/job/tcwg_bmk-code_speed-spec2k6-gnu-aarch64-master-O3_... --fail

# Reproduce bad build (cd bad; ../jenkins-scripts/tcwg_bmk-build.sh ^^ true %%rr[top_artifacts] artifacts) # Reproduce good build (cd good; ../jenkins-scripts/tcwg_bmk-build.sh ^^ true %%rr[top_artifacts] artifacts) </cut>

Full commit (up to 1000 lines): <cut> commit 569cfcc6bf35c28112ca8d7112e9eb4a22bed5b8 Author: Samuel Thibault samuel.thibault@ens-lyon.org Date: Sun Jan 15 20:54:42 2023 +0100

hurd: Fix _NOFLSH value

shifting 1 (thus an integer) left 31 bit is undefined behavior. We have to make it an unsigned integer to properly get 0x80000000 (like done in other places). --- bits/termios.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/bits/termios.h b/bits/termios.h index ae62d00853..4439c2f14e 100644 --- a/bits/termios.h +++ b/bits/termios.h @@ -246,7 +246,7 @@ struct termios # define NOKERNINFO (1 << 25) /* Disable VSTATUS. */ # define PENDIN (1 << 29) /* Retype pending input (state). */ #endif -#define _NOFLSH (1 << 31) /* Disable flush after interrupt. */ +#define _NOFLSH (1U << 31) /* Disable flush after interrupt. */ #define NOFLSH _NOFLSH

/* Control characters. */ </cut>