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* x86: Don't set Prefer_No_AVX512 for processors with AVX512 and AVX-VNNIH.J. Lu2021-12-061-2/+5
| | | | | | Don't set Prefer_No_AVX512 on processors with AVX512 and AVX-VNNI since they won't lower CPU frequency when ZMM load and store instructions are used.
* linux: Add generic ioctl implementationAdhemerval Zanella2021-12-063-31/+85
| | | | The powerpc is refactor to use the default implementation.
* linux: Add generic syscall implementationAdhemerval Zanella2021-12-064-67/+65
| | | | | It allows also to remove hppa specific implementation and simplify riscv implementation a bit.
* misc, nptl: Remove stray references to __condvar_load_64_relaxedFlorian Weimer2021-12-062-3/+3
| | | | | | The function was renamed to __atomic_wide_counter_load_relaxed in commit 8bd336a00a5311bf7a9e99b3b0e9f01ff5faa74b ("nptl: Extract <bits/atomic_wide_counter.h> from pthread_cond_common.c").
* csu: Always use __executable_start in gmon-start.cFlorian Weimer2021-12-054-89/+3
| | | | | | | | | | | | | | Current binutils defines __executable_start as the lowest text address, so using the entry point address as a fallback is no longer necessary. As a result, overriding <entry.h> is only necessary if the entry point is not called _start. The previous approach to define __ASSEMBLY__ to suppress the declaration breaks if headers included by <entry.h> are not compatible with __ASSEMBLY__. This happens with rseq integration because it is necessary to include kernel headers in more places. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* elf: execve statically linked programs instead of crashing [BZ #28648]Florian Weimer2021-12-056-8/+161
| | | | | | | | | | | | | | | Programs without dynamic dependencies and without a program interpreter are now run via execve. Previously, the dynamic linker either crashed while attempting to read a non-existing dynamic segment (looking for DT_AUDIT/DT_DEPAUDIT data), or the self-relocated in the static PIE executable crashed because the outer dynamic linker had already applied RELRO protection. <dl-execve.h> is needed because execve is not available in the dynamic loader on Hurd. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* Add --with-timeoutfactor=NUM to specify TIMEOUTFACTORH.J. Lu2021-12-046-1/+37
| | | | | | | | | On Ice Lake and Tiger Lake laptops, some test programs timeout when there are 3 "make check -j8" runs in parallel. Add --with-timeoutfactor=NUM to specify an integer to scale the timeout of test programs, which can be overriden by TIMEOUTFACTOR environment variable. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* x86-64: Use notl in EVEX strcmp [BZ #28646]Noah Goldstein2021-12-032-6/+36
| | | | | | | | Must use notl %edi here as lower bits are for CHAR comparisons potentially out of range thus can be 0 without indicating mismatch. This fixes BZ #28646. Co-Authored-By: H.J. Lu <hjl.tools@gmail.com>
* nptl: Increase default TCB alignment to 32Florian Weimer2021-12-0318-50/+4
| | | | | | | | | | rseq support will use a 32-byte aligned field in struct pthread, so the whole struct needs to have at least that alignment. nptl/tst-tls3mod.c uses TCB_ALIGNMENT, therefore include <descr.h> to obtain the fallback definition. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* elf: add definition for ELF_NOTE_FDO and NT_FDO_PACKAGING_METADATA noteLuca Boccassi2021-12-021-0/+6
| | | | | | | As defined on: https://systemd.io/COREDUMP_PACKAGE_METADATA/ this note will be used starting from Fedora 36. Signed-off-by: Luca Boccassi <bluca@debian.org>
* AArch64: Improve A64FX memcpyWilco Dijkstra2021-12-021-321/+225
| | | | | | | | | | | | | v2 is a complete rewrite of the A64FX memcpy. Performance is improved by streamlining the code, aligning all large copies and using a single unrolled loop for all sizes. The code size for memcpy and memmove goes down from 1796 bytes to 868 bytes. Performance is better in all cases: bench-memcpy-random is 2.3% faster overall, bench-memcpy-large is ~33% faster for large sizes, bench-memcpy-walk is 25% faster for small sizes and 20% for the largest sizes. The geomean of all tests in bench-memcpy is 5.1% faster, and total time is reduced by 4%. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* AArch64: Optimize memcmpWilco Dijkstra2021-12-021-107/+134
| | | | | | | | Rewrite memcmp to improve performance. On small and medium inputs performance is 10-20% better. Large inputs use a SIMD loop processing 64 bytes per iteration, which is 30-50% faster depending on the size. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* powerpc64[le]: Fix CFI and LR save address for asm syscalls [BZ #28532]Matheus Castanho2021-11-301-4/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Syscalls based on the assembly templates are missing CFI for r31, which gets clobbered when scv is used, and info for LR is inaccurate, placed in the wrong LOC and not using the proper offset. LR was also being saved to the callee's frame, while the ABI mandates it to be saved to the caller's frame. These are fixed by this commit. After this change: $ readelf -wF libc.so.6 | grep 0004b9d4.. -A 7 && objdump --disassemble=kill libc.so.6 00004a48 0000000000000020 00004a4c FDE cie=00000000 pc=000000000004b9d4..000000000004ba3c LOC CFA r31 ra 000000000004b9d4 r1+0 u u 000000000004b9e4 r1+48 u u 000000000004b9e8 r1+48 c-16 u 000000000004b9fc r1+48 c-16 c+16 000000000004ba08 r1+48 c-16 000000000004ba18 r1+48 u 000000000004ba1c r1+0 u libc.so.6: file format elf64-powerpcle Disassembly of section .text: 000000000004b9d4 <kill>: 4b9d4: 1f 00 4c 3c addis r2,r12,31 4b9d8: 2c c3 42 38 addi r2,r2,-15572 4b9dc: 25 00 00 38 li r0,37 4b9e0: d1 ff 21 f8 stdu r1,-48(r1) 4b9e4: 20 00 e1 fb std r31,32(r1) 4b9e8: 98 8f ed eb ld r31,-28776(r13) 4b9ec: 10 00 ff 77 andis. r31,r31,16 4b9f0: 1c 00 82 41 beq 4ba0c <kill+0x38> 4b9f4: a6 02 28 7d mflr r9 4b9f8: 40 00 21 f9 std r9,64(r1) 4b9fc: 01 00 00 44 scv 0 4ba00: 40 00 21 e9 ld r9,64(r1) 4ba04: a6 03 28 7d mtlr r9 4ba08: 08 00 00 48 b 4ba10 <kill+0x3c> 4ba0c: 02 00 00 44 sc 4ba10: 00 00 bf 2e cmpdi cr5,r31,0 4ba14: 20 00 e1 eb ld r31,32(r1) 4ba18: 30 00 21 38 addi r1,r1,48 4ba1c: 18 00 96 41 beq cr5,4ba34 <kill+0x60> 4ba20: 01 f0 20 39 li r9,-4095 4ba24: 40 48 23 7c cmpld r3,r9 4ba28: 20 00 e0 4d bltlr+ 4ba2c: d0 00 63 7c neg r3,r3 4ba30: 08 00 00 48 b 4ba38 <kill+0x64> 4ba34: 20 00 e3 4c bnslr+ 4ba38: c8 32 fe 4b b 2ed00 <__syscall_error> ... 4ba44: 40 20 0c 00 .long 0xc2040 4ba48: 68 00 00 00 .long 0x68 4ba4c: 06 00 5f 5f rlwnm r31,r26,r0,0,3 4ba50: 6b 69 6c 6c xoris r12,r3,26987
* linux: Implement pipe in terms of __NR_pipe2Adhemerval Zanella2021-11-3010-221/+3
| | | | | | | | | The syscall pipe2 was added in linux 2.6.27 and glibc requires linux 3.2.0. The patch removes the arch-specific implementation for alpha, ia64, mips, sh, and sparc which requires a different kernel ABI than the usual one. Checked on x86_64-linux-gnu and with a build for the affected ABIs.
* linux: Implement mremap in CAdhemerval Zanella2021-11-303-1/+42
| | | | | | | | | Variadic function calls in syscalls.list does not work for all ABIs (for instance where the argument are passed on the stack instead of registers) and might have underlying issues depending of the variadic type (for instance if a 64-bit argument is used). Checked on x86_64-linux-gnu.
* linux: Add prlimit64 C implementationAdhemerval Zanella2021-11-3018-27/+47
| | | | | | | | | | | The LFS prlimit64 requires a arch-specific implementation in syscalls.list. Instead add a generic one that handles the required symbol alias for __RLIM_T_MATCHES_RLIM64_T. HPPA is the only outlier which requires a different default symbol. Checked on x86_64-linux-gnu and with build for the affected ABIs.
* elf: Include <stdbool.h> in tst-tls20.cFlorian Weimer2021-11-301-0/+1
| | | | The test uses the bool type.
* elf: Include <stdint.h> in tst-tls20.cFlorian Weimer2021-11-301-0/+1
| | | | The test uses standard integer types.
* hurd: Let report-wait use a weak reference to _hurd_itimer_threadSamuel Thibault2021-11-281-5/+0
| | | | libc.so.0.3 does not seem to need this defined any more.
* linux: Use /proc/stat fallback for __get_nprocs_conf (BZ #28624)Adhemerval Zanella2021-11-251-25/+35
| | | | | | | The /proc/statm fallback was removed by f13fb81ad3159 if sysfs is not available, reinstate it. Checked on x86_64-linux-gnu.
* linux: Add fanotify_mark C implementationAdhemerval Zanella2021-11-2518-22/+42
| | | | | | | | | Passing 64-bit arguments on syscalls.list is tricky: it requires to reimplement the expected kernel abi in each architecture. This is way to better to represent in C code where we already have macros for this (SYSCALL_LL64). Checked on x86_64-linux-gnu.
* linux: Only build fstatat fallback if requiredAdhemerval Zanella2021-11-251-7/+11
| | | | | | | For 32-bit architecture with __ASSUME_STATX there is no need to build fstatat64_time64_stat. Checked on i686-linux-gnu.
* regex: fix buffer read overrun in search [BZ#28470]Paul Eggert2021-11-241-4/+3
| | | | | | Problem reported by Benno Schulenberg in: https://lists.gnu.org/r/bug-gnulib/2021-10/msg00035.html * posix/regexec.c (re_search_internal): Use better bounds check.
* x86-64: Add vector sin/sinf to libmvec microbenchmarkSunil K Pandey2021-11-243-0/+8201
| | | | | | | | | | | | | | | | | | | | Add vector sin/sinf and input files to libmvec microbenchmark. libmvec-sin-inputs: 90% Normal random distribution range: (-DBL_MAX, DBL_MAX) mean: 0.0 sigma: 5.0 10% uniform random distribution in range (-1000.0, 1000.0) libmvec-sinf-inputs: 90% Normal random distribution range: (-FLT_MAX, FLT_MAX) mean: 0.0f sigma: 5.0f 10% uniform random distribution in range (-1000.0f, 1000.0f) Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86-64: Add vector pow/powf to libmvec microbenchmarkSunil K Pandey2021-11-243-0/+8201
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add vector pow/powf and input files to libmvec microbenchmark. libmvec-pow-inputs: arg1: 90% Normal random distribution range: (0.0, 256.0) mean: 0.0 sigma: 32.0 10% uniform random distribution in range (0.0, 256.0) arg2: 90% Normal random distribution range: (-127.0, 127.0) mean: 0.0 sigma: 16.0 10% uniform random distribution in range (-127.0, 127.0) libmvec-powf-inputs: arg1: 90% Normal random distribution range: (0.0f, 100.0f) mean: 0.0f sigma: 16.0f 10% uniform random distribution in range (0.0f, 100.0f) arg2: 90% Normal random distribution range: (-10.0f, 10.0f) mean: 0.0f sigma: 8.0f 10% uniform random distribution in range (-10.0f, 10.0f) Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86-64: Add vector log/logf to libmvec microbenchmarkSunil K Pandey2021-11-243-0/+8201
| | | | | | | | | | | | | | | | | | | | Add vector log/logf and input files to libmvec microbenchmark. libmvec-log-inputs: 70% Normal random distribution range: (0.0, DBL_MAX) mean: 1.0 sigma: 50.0 30% uniform random distribution in range (0.0, DBL_MAX) libmvec-logf-inputs: 70% Normal random distribution range: (0.0f, FLT_MAX) mean: 1.0f sigma: 50.0f 30% uniform random distribution in range (0.0f, FLT_MAX) Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86-64: Add vector exp/expf to libmvec microbenchmarkSunil K Pandey2021-11-243-0/+8201
| | | | | | | | | | | | | | | | | | | | Add vector exp/expf and input files to libmvec microbenchmark. libmvec-exp-inputs: 90% Normal random distribution range: (-708.0, 709.0) mean: 0.0 sigma: 16.0 10% uniform random distribution in range (-500.0, 500.0) libmvec-expf-inputs: 90% Normal random distribution range: (-87.0f, 88.0f) mean: 0.0f sigma: 8.0f 10% uniform random distribution in range (-50.0f, 50.0f) Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86-64: Add vector cos/cosf to libmvec microbenchmarkSunil K Pandey2021-11-243-0/+8201
| | | | | | | | | | | | | | | | | | | | Add vector cos/cosf and input files to libmvec microbenchmark. libmvec-cos-inputs: 90% Normal random distribution range: (-DBL_MAX, DBL_MAX) mean: 0.0 sigma: 5.0 10% uniform random distribution in range (-1000.0, 1000.0) libmvec-cosf-inputs: 90% Normal random distribution range: (-FLT_MAX, FLT_MAX) mean: 0.0f sigma: 5.0f 10% uniform random distribution in range (-1000.0f, 1000.0f) Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* io: Refactor close_range and closefromAdhemerval Zanella2021-11-2415-68/+76
| | | | | | | | | | | | | | | | | | | | | | | | | | Now that Hurd implementis both close_range and closefrom (f2c996597d), we can make close_range() a base ABI, and make the default closefrom() implementation on top of close_range(). The generic closefrom() implementation based on __getdtablesize() is moved to generic close_range(). On Linux it will be overriden by the auto-generation syscall while on Hurd it will be a system specific implementation. The closefrom() now calls close_range() and __closefrom_fallback(). Since on Hurd close_range() does not fail, __closefrom_fallback() is an empty static inline function set by__ASSUME_CLOSE_RANGE. The __ASSUME_CLOSE_RANGE also allows optimize Linux __closefrom_fallback() implementation when --enable-kernel=5.9 or higher is used. Finally the Linux specific tst-close_range.c is moved to io and enabled as default. The Linuxism and CLOSE_RANGE_UNSHARE are guarded so it can be built for Hurd (I have not actually test it). Checked on x86_64-linux-gnu, i686-linux-gnu, and with a i686-gnu build.
* nptl: Do not set signal mask on second setjmp return [BZ #28607]Florian Weimer2021-11-243-2/+48
| | | | | | | | | | | | __libc_signal_restore_set was in the wrong place: It also ran when setjmp returned the second time (after pthread_exit or pthread_cancel). This is observable with blocked pending signals during thread exit. Fixes commit b3cae39dcbfa2432b3f3aa28854d8ac57f0de1b8 ("nptl: Start new threads with all signals blocked [BZ #25098]"). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* powerpc: Define USE_PPC64_NOTOC iff compiler supports itAdhemerval Zanella2021-11-222-24/+43
| | | | | | | | | | | | | | | | | | The @notoc usage only yields an advantage on ISA 3.1+ machine (power10) and for ld.bfd also when it sees pcrel relocations used on the code (generated if compiler targets ISA 3.1+). On bfd case ISA 3.1+ instruction on stubs are used iff linker also sees the new pc-relative relocations (for instance R_PPC64_D34), otherwise it generates default stubs (ppc64_elf_check_relocs:4700). This patch also help on linkers that do not implement this optimization, since building for older ISA (such as 3.0 / power9) will also trigger power10 stubs generation in the assembly code uses the NOTOC imacro. Checked on powerpc64le-linux-gnu. Reviewed-by: Fangrui Song <maskray@google.com> Reviewed-by: Tulio Magno Quites Machado Filho <tuliom@linux.ibm.com>
* setjmp: Replace jmp_buf-macros.h with jmp_buf-macros.symAdhemerval Zanella2021-11-2233-297/+72
| | | | | | | | | | | | It requires less boilerplate code for newer ports. The _Static_assert checks from internal setjmp are moved to its own internal test since setjmp.h is included early by multiple headers (to generate rtld-sizes.sym). The riscv jmp_buf-macros.h check is also redundant, it is already done by riscv configure.ac. Checked with a build for the affected architectures.
* Update kernel version to 5.15 in tst-mman-consts.pyJoseph Myers2021-11-221-1/+1
| | | | | | | | This patch updates the kernel version in the test tst-mman-consts.py to 5.15. (There are no new MAP_* constants covered by this test in 5.15 that need any other header changes.) Tested with build-many-glibcs.py.
* socket: Do not use AF_NETLINK in __opensockFlorian Weimer2021-11-221-8/+1
| | | | | | | It is not possible to use interface ioctls with netlink sockets on all Linux kernels. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Move la_activity (LA_ACT_ADD) after _dl_add_to_namespace_list() (BZ #28062)Adhemerval Zanella2021-11-185-37/+271
| | | | | | | | It ensures that the the namespace is guaranteed to not be empty. Checked on x86_64-linux-gnu. Reviewed-by: Florian Weimer <fweimer@redhat.com>
* Add PF_MCTP, AF_MCTP from Linux 5.15 to bits/socket.hJoseph Myers2021-11-171-1/+3
| | | | | | | Linux 5.15 adds a new address / protocol family PF_MCTP / AF_MCTP; add these constants to bits/socket.h. Tested for x86_64.
* malloc: Fix malloc debug for 2.35 onwardsStafford Horne2021-11-171-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The change 1e5a5866cb ("Remove malloc hooks [BZ #23328]") has broken ports that are using GLIBC_2_35, like the new OpenRISC port I am working on. The libc_malloc_debug.so library used to bring in the debug infrastructure is currently essentially empty for GLIBC_2_35 ports like mine causing mtrace tests to fail: cat sysdeps/unix/sysv/linux/or1k/shlib-versions DEFAULT GLIBC_2.35 ld=ld-linux-or1k.so.1 FAIL: posix/bug-glob2-mem FAIL: posix/bug-regex14-mem FAIL: posix/bug-regex2-mem FAIL: posix/bug-regex21-mem FAIL: posix/bug-regex31-mem FAIL: posix/bug-regex36-mem FAIL: malloc/tst-mtrace. The issue seems to be with the ifdefs in malloc/malloc-debug.c. The ifdefs are currently essentially exluding all symbols for ports > 2.35. Removing the top level SHLIB_COMPAT ifdef allows things to just work. Fixes: 1e5a5866cb ("Remove malloc hooks [BZ #23328]") Reviewed-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* elf: Introduce GLRO (dl_libc_freeres), called from __libc_freeresFlorian Weimer2021-11-175-1/+38
| | | | | | | This will be used to deallocate memory allocated using the non-minimal malloc. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* nptl: Extract <bits/atomic_wide_counter.h> from pthread_cond_common.cFlorian Weimer2021-11-179-198/+310
| | | | | | | | | | | | | And make it an installed header. This addresses a few aliasing violations (which do not seem to result in miscompilation due to the use of atomics), and also enables use of wide counters in other parts of the library. The debug output in nptl/tst-cond22 has been adjusted to print the 32-bit values instead because it avoids a big-endian/little-endian difference. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* x86-64: Create microbenchmark infrastructure for libmvecSunil K Pandey2021-11-164-0/+642
| | | | | | | | | | | | | Add python script to generate libmvec microbenchmark from the input values for each libmvec function using skeleton benchmark template. Creates double and float benchmarks with vector length 1, 2, 4, 8, and 16 for each libmvec function. Vector length 1 corresponds to scalar version of function and is included for vector function perf comparison. Co-authored-by: Haochen Jiang <haochen.jiang@intel.com> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* elf: hidden visibility for __minimal_malloc functionsAdhemerval Zanella2021-11-161-0/+5
| | | | | | | | Since b05fae4d8e34, __minimal malloc code is used during static startup before PIE self-relocation (_dl_relocate_static_pie). So it requires the same fix done for other objects by 47618209d05a. Checked on aarch64, x86_64, and i686 with and without static-pie.
* elf: Use a temporary file to generate Makefile fragments [BZ #28550]H.J. Lu2021-11-161-2/+8
| | | | | | | | | | | | 1. Use a temporary file to generate Makefile fragments for DSO sorting tests and use -include on them. 2. Add Makefile fragments to postclean-generated so that a "make clean" removes the autogenerated fragments and a subsequent "make" regenerates them. This partially fixes BZ #28550. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* dso-ordering-test.py: Put all sources in one directory [BZ #28550]H.J. Lu2021-11-151-13/+34
| | | | | | | | | | | | | | | | | | | | | | Put all sources for DSO sorting tests in the dso-sort-tests-src directory and compile test relocatable objects with $(objpfx)tst-dso-ordering1-dir/tst-dso-ordering1-a.os: $(objpfx)dso-sort-tests-src/tst-dso-ordering1-a.c $(compile.c) $(OUTPUT_OPTION) to avoid random $< values from $(before-compile) when compiling test relocatable objects with $(objpfx)%$o: $(objpfx)%.c $(before-compile); $$(compile-command.c) compile-command.c = $(compile.c) $(OUTPUT_OPTION) $(compile-mkdep-flags) compile.c = $(CC) $< -c $(CFLAGS) $(CPPFLAGS) for 3 "make -j 28" parallel builds on a machine with 112 cores at the same time. This partially fixes BZ #28550. Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* elf: Move LAV_CURRENT to link_lavcurrent.hAdhemerval Zanella2021-11-153-2/+27
| | | | No functional change.
* Move assignment out of the CAS conditionH.J. Lu2021-11-152-8/+6
| | | | | | | | | | | | | | | | | | | | | | | | Update commit 49302b8fdf9103b6fc0a398678668a22fa19574c Author: H.J. Lu <hjl.tools@gmail.com> Date: Thu Nov 11 06:54:01 2021 -0800 Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537] Replace boolean CAS with value CAS to avoid the extra load. and commit 0b82747dc48d5bf0871bdc6da8cb6eec1256355f Author: H.J. Lu <hjl.tools@gmail.com> Date: Thu Nov 11 06:31:51 2021 -0800 Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537] Replace boolean CAS with value CAS to avoid the extra load. by moving assignment out of the CAS condition.
* Add a comment for --enable-initfini-array [BZ #27945]H.J. Lu2021-11-131-1/+3
| | | | | Document that --enable-initfini-array is enabled by default in GCC 12, which can be removed when GCC 12 becomes the minimum requirement.
* tst-tzset: output reason when creating 4GiB file failsStafford Horne2021-11-131-0/+8
| | | | | | | Currently, if the temporary file creation fails the create_tz_file function returns NULL. The NULL pointer is then passed to setenv which causes a SIGSEGV. Rather than failing with a SIGSEGV print a warning and exit.
* Add LLL_MUTEX_READ_LOCK [BZ #28537]H.J. Lu2021-11-121-0/+7
| | | | | | | | | | | | | | | | CAS instruction is expensive. From the x86 CPU's point of view, getting a cache line for writing is more expensive than reading. See Appendix A.2 Spinlock in: https://www.intel.com/content/dam/www/public/us/en/documents/white-papers/xeon-lock-scaling-analysis-paper.pdf The full compare and swap will grab the cache line exclusive and cause excessive cache line bouncing. Add LLL_MUTEX_READ_LOCK to do an atomic load and skip CAS in spinlock loop if compare may fail to reduce cache line bouncing on contended locks. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* Avoid extra load with CAS in __pthread_mutex_clocklock_common [BZ #28537]H.J. Lu2021-11-121-5/+5
| | | | | | Replace boolean CAS with value CAS to avoid the extra load. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
* Avoid extra load with CAS in __pthread_mutex_lock_full [BZ #28537]H.J. Lu2021-11-121-5/+5
| | | | | | Replace boolean CAS with value CAS to avoid the extra load. Reviewed-by: Szabolcs Nagy <szabolcs.nagy@arm.com>
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