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* x86: ZERO_UPPER_VEC_REGISTERS_RETURN_XTEST expect no transactionsNoah Goldstein2022-06-071-3/+3
| | | | | | | | Give fall-through path to `vzeroupper` and taken-path to `vzeroall`. Generally even on machines with RTM the expectation is the string-library functions will not be called in transactions. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Shrink code size of memchr-evex.SNoah Goldstein2022-06-071-21/+25
| | | | | | | | | | | | | This is not meant as a performance optimization. The previous code was far to liberal in aligning targets and wasted code size unnecissarily. The total code size saving is: 64 bytes There are no non-negligible changes in the benchmarks. Geometric Mean of all benchmarks New / Old: 1.000 Full xcheck passes on x86_64. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Shrink code size of memchr-avx2.SNoah Goldstein2022-06-072-50/+60
| | | | | | | | | | | | | This is not meant as a performance optimization. The previous code was far to liberal in aligning targets and wasted code size unnecissarily. The total code size saving is: 59 bytes There are no major changes in the benchmarks. Geometric Mean of all benchmarks New / Old: 0.967 Full xcheck passes on x86_64. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize memrchr-avx2.SNoah Goldstein2022-06-072-278/+257
| | | | | | | | | | | | | | | | | | | | | | | | | | The new code: 1. prioritizes smaller user-arg lengths more. 2. optimizes target placement more carefully 3. reuses logic more 4. fixes up various inefficiencies in the logic. The biggest case here is the `lzcnt` logic for checking returns which saves either a branch or multiple instructions. The total code size saving is: 306 bytes Geometric Mean of all benchmarks New / Old: 0.760 Regressions: There are some regressions. Particularly where the length (user arg length) is large but the position of the match char is near the beginning of the string (in first VEC). This case has roughly a 10-20% regression. This is because the new logic gives the hot path for immediate matches to shorter lengths (the more common input). This case has roughly a 15-45% speedup. Full xcheck passes on x86_64. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize memrchr-evex.SNoah Goldstein2022-06-071-271/+268
| | | | | | | | | | | | | | | | | | | | | | | | | | The new code: 1. prioritizes smaller user-arg lengths more. 2. optimizes target placement more carefully 3. reuses logic more 4. fixes up various inefficiencies in the logic. The biggest case here is the `lzcnt` logic for checking returns which saves either a branch or multiple instructions. The total code size saving is: 263 bytes Geometric Mean of all benchmarks New / Old: 0.755 Regressions: There are some regressions. Particularly where the length (user arg length) is large but the position of the match char is near the beginning of the string (in first VEC). This case has roughly a 20% regression. This is because the new logic gives the hot path for immediate matches to shorter lengths (the more common input). This case has roughly a 35% speedup. Full xcheck passes on x86_64. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize memrchr-sse2.SNoah Goldstein2022-06-071-321/+292
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new code: 1. prioritizes smaller lengths more. 2. optimizes target placement more carefully. 3. reuses logic more. 4. fixes up various inefficiencies in the logic. The total code size saving is: 394 bytes Geometric Mean of all benchmarks New / Old: 0.874 Regressions: 1. The page cross case is now colder, especially re-entry from the page cross case if a match is not found in the first VEC (roughly 50%). My general opinion with this patch is this is acceptable given the "coldness" of this case (less than 4%) and generally performance improvement in the other far more common cases. 2. There are some regressions 5-15% for medium/large user-arg lengths that have a match in the first VEC. This is because the logic was rewritten to optimize finds in the first VEC if the user-arg length is shorter (where we see roughly 20-50% performance improvements). It is not always the case this is a regression. My intuition is some frontend quirk is partially explaining the data although I haven't been able to find the root cause. Full xcheck passes on x86_64. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Add COND_VZEROUPPER that can replace vzeroupper if no `ret`Noah Goldstein2022-06-072-0/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The RTM vzeroupper mitigation has no way of replacing inline vzeroupper not before a return. This can be useful when hoisting a vzeroupper to save code size for example: ``` L(foo): cmpl %eax, %edx jz L(bar) tzcntl %eax, %eax addq %rdi, %rax VZEROUPPER_RETURN L(bar): xorl %eax, %eax VZEROUPPER_RETURN ``` Can become: ``` L(foo): COND_VZEROUPPER cmpl %eax, %edx jz L(bar) tzcntl %eax, %eax addq %rdi, %rax ret L(bar): xorl %eax, %eax ret ``` This code does not change any existing functionality. There is no difference in the objdump of libc.so before and after this patch. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Create header for VEC classes in x86 strings libraryNoah Goldstein2022-06-077-0/+327
| | | | | | | | | | This patch does not touch any existing code and is only meant to be a tool for future patches so that simple source files can more easily be maintained to target multiple VEC classes. There is no difference in the objdump of libc.so before and after this patch. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86_64: Add strstr function with 512-bit EVEXRaghuveer Devulapalli2022-06-064-4/+242
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Adding a 512-bit EVEX version of strstr. The algorithm works as follows: (1) We spend a few cycles at the begining to peek into the needle. We locate an edge in the needle (first occurance of 2 consequent distinct characters) and also store the first 64-bytes into a zmm register. (2) We search for the edge in the haystack by looking into one cache line of the haystack at a time. This avoids having to read past a page boundary which can cause a seg fault. (3) If an edge is found in the haystack we first compare the first 64-bytes of the needle (already stored in a zmm register) before we proceed with a full string compare performed byte by byte. Benchmarking results: (old = strstr_sse2_unaligned, new = strstr_avx512) Geometric mean of all benchmarks: new / old = 0.66 Difficult skiptable(0) : new / old = 0.02 Difficult skiptable(1) : new / old = 0.01 Difficult 2-way : new / old = 0.25 Difficult testing first 2 : new / old = 1.26 Difficult skiptable(0) : new / old = 0.05 Difficult skiptable(1) : new / old = 0.06 Difficult 2-way : new / old = 0.26 Difficult testing first 2 : new / old = 1.05 Difficult skiptable(0) : new / old = 0.42 Difficult skiptable(1) : new / old = 0.24 Difficult 2-way : new / old = 0.21 Difficult testing first 2 : new / old = 1.04 Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86_64: Optimize sincos where sin/cos is optimized (bug 29193)Andreas Schwab2022-06-015-3/+48
| | | | | | | The compiler may substitute calls to sin or cos with calls to sincos, thus we should have the same optimized implementations for sincos. The optimized implementations may produce results that differ, that also makes sure that the sincos call aggrees with the sin and cos calls.
* x86_64: Remove _dl_skip_args usageAdhemerval Zanella2022-05-302-22/+3
| | | | | | | | | | | Since ad43cac44a the generic code already shuffles the argv/envp/auxv on the stack to remove the ld.so own arguments and thus _dl_skip_args is always 0. So there is no need to adjust the argc or argv. Checked on x86_64-linux-gnu and i686-linux-gnu. Reviewed-by: H.J. Lu <hjl.tools@gmail.com> Reviewed-by: Carlos O'Donell <carlos@redhat.com>
* x86-64: Ignore r_addend for R_X86_64_GLOB_DAT/R_X86_64_JUMP_SLOTH.J. Lu2022-05-261-2/+4
| | | | | | | | According to x86-64 psABI, r_addend should be ignored for R_X86_64_GLOB_DAT and R_X86_64_JUMP_SLOT. Since linkers always set their r_addends to 0, we can ignore their r_addends. Reviewed-by: Fangrui Song <maskray@google.com>
* x86_64: Implement evex512 version of strlen, strnlen, wcslen and wcsnlenSunil K Pandey2022-05-267-0/+346
| | | | | | | | | | | | | | | This patch implements following evex512 version of string functions. Perf gain for evex512 version is up to 50% as compared to evex, depending on length and alignment. Placeholder function, not used by any processor at the moment. - String length function using 512 bit vectors. - String N length using 512 bit vectors. - Wide string length using 512 bit vectors. - Wide string N length using 512 bit vectors. Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* math: Add math-use-builtins-fabs (BZ#29027)Adhemerval Zanella2022-05-231-28/+0
| | | | | | | | | | | | | | | | | | Both float, double, and _Float128 are assumed to be supported (float and double already only uses builtins). Only long double is parametrized due GCC bug 29253 which prevents its usage on powerpc. It allows to remove i686, ia64, x86_64, powerpc, and sparc arch specific implementation. On ia64 it also fixes the sNAN handling: math/test-float64x-fabs math/test-ldouble-fabs Checked on x86_64-linux-gnu, i686-linux-gnu, powerpc-linux-gnu, powerpc64-linux-gnu, sparc64-linux-gnu, and ia64-linux-gnu.
* x86_64: Remove bzero optimizationAdhemerval Zanella2022-05-1611-235/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Both symbols are marked as legacy in POSIX.1-2001 and removed on POSIX.1-2008, although the prototypes are defined for _GNU_SOURCE or _DEFAULT_SOURCE. GCC also replaces bcopy with a memmove and bzero with memset on default configuration (to actually get a bzero libc call the code requires to omit string.h inclusion and built with -fno-builtin), so it is highly unlikely programs are actually calling libc bzero symbol. On a recent Linux distro (Ubuntu 22.04), there is no bzero calls by the installed binaries. $ cat count_bstring.sh #!/bin/bash files=`IFS=':';for i in $PATH; do test -d "$i" && find "$i" -maxdepth 1 -executable -type f; done` total=0 for file in $files; do symbols=`objdump -R $file 2>&1` if [ $? -eq 0 ]; then ncalls=`echo $symbols | grep -w $1 | wc -l` ((total=total+ncalls)) if [ $ncalls -gt 0 ]; then echo "$file: $ncalls" fi fi done echo "TOTAL=$total" $ ./count_bstring.sh bzero TOTAL=0 Checked on x86_64-linux-gnu.
* nptl: Add backoff mechanism to spinlock loopWangyang Guo2022-05-091-0/+39
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When mutiple threads waiting for lock at the same time, once lock owner releases the lock, waiters will see lock available and all try to lock, which may cause an expensive CAS storm. Binary exponential backoff with random jitter is introduced. As try-lock attempt increases, there is more likely that a larger number threads compete for adaptive mutex lock, so increase wait time in exponential. A random jitter is also added to avoid synchronous try-lock from other threads. v2: Remove read-check before try-lock for performance. v3: 1. Restore read-check since it works well in some platform. 2. Make backoff arch dependent, and enable it for x86_64. 3. Limit max backoff to reduce latency in large critical section. v4: Fix strict-prototypes error in sysdeps/nptl/pthread_mutex_backoff.h v5: Commit log updated for regression in large critical section. Result of pthread-mutex-locks bench Test Platform: Xeon 8280L (2 socket, 112 CPUs in total) First Row: thread number First Col: critical section length Values: backoff vs upstream, time based, low is better non-critical-length: 1 1 2 4 8 16 32 64 112 140 0 0.99 0.58 0.52 0.49 0.43 0.44 0.46 0.52 0.54 1 0.98 0.43 0.56 0.50 0.44 0.45 0.50 0.56 0.57 2 0.99 0.41 0.57 0.51 0.45 0.47 0.48 0.60 0.61 4 0.99 0.45 0.59 0.53 0.48 0.49 0.52 0.64 0.65 8 1.00 0.66 0.71 0.63 0.56 0.59 0.66 0.72 0.71 16 0.97 0.78 0.91 0.73 0.67 0.70 0.79 0.80 0.80 32 0.95 1.17 0.98 0.87 0.82 0.86 0.89 0.90 0.90 64 0.96 0.95 1.01 1.01 0.98 1.00 1.03 0.99 0.99 128 0.99 1.01 1.01 1.17 1.08 1.12 1.02 0.97 1.02 non-critical-length: 32 1 2 4 8 16 32 64 112 140 0 1.03 0.97 0.75 0.65 0.58 0.58 0.56 0.70 0.70 1 0.94 0.95 0.76 0.65 0.58 0.58 0.61 0.71 0.72 2 0.97 0.96 0.77 0.66 0.58 0.59 0.62 0.74 0.74 4 0.99 0.96 0.78 0.66 0.60 0.61 0.66 0.76 0.77 8 0.99 0.99 0.84 0.70 0.64 0.66 0.71 0.80 0.80 16 0.98 0.97 0.95 0.76 0.70 0.73 0.81 0.85 0.84 32 1.04 1.12 1.04 0.89 0.82 0.86 0.93 0.91 0.91 64 0.99 1.15 1.07 1.00 0.99 1.01 1.05 0.99 0.99 128 1.00 1.21 1.20 1.22 1.25 1.31 1.12 1.10 0.99 non-critical-length: 128 1 2 4 8 16 32 64 112 140 0 1.02 1.00 0.99 0.67 0.61 0.61 0.61 0.74 0.73 1 0.95 0.99 1.00 0.68 0.61 0.60 0.60 0.74 0.74 2 1.00 1.04 1.00 0.68 0.59 0.61 0.65 0.76 0.76 4 1.00 0.96 0.98 0.70 0.63 0.63 0.67 0.78 0.77 8 1.01 1.02 0.89 0.73 0.65 0.67 0.71 0.81 0.80 16 0.99 0.96 0.96 0.79 0.71 0.73 0.80 0.84 0.84 32 0.99 0.95 1.05 0.89 0.84 0.85 0.94 0.92 0.91 64 1.00 0.99 1.16 1.04 1.00 1.02 1.06 0.99 0.99 128 1.00 1.06 0.98 1.14 1.39 1.26 1.08 1.02 0.98 There is regression in large critical section. But adaptive mutex is aimed for "quick" locks. Small critical section is more common when users choose to use adaptive pthread_mutex. Signed-off-by: Wangyang Guo <wangyang.guo@intel.com> Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* benchtests: Better libmvec integrationSiddhesh Poyarekar2022-04-291-4/+0
| | | | | | | | Improve libmvec benchmark integration so that in future other architectures may be able to run their libmvec benchmarks as well. This now allows libmvec benchmarks to be run with `make BENCHSET=bench-math`. Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* benchtests: Add UNSUPPORTED benchmark statusSiddhesh Poyarekar2022-04-291-6/+6
| | | | | | | | | | | | The libmvec benchmarks print a message indicating that a certain CPU feature is unsupported and exit prematurelyi, which breaks the JSON in bench.out. Handle this more elegantly in the bench makefile target by adding support for an UNSUPPORTED exit status (77) so that bench.out continues to have output for valid tests. Signed-off-by: Siddhesh Poyarekar <siddhesh@sourceware.org>
* x86: Optimize {str|wcs}rchr-evexNoah Goldstein2022-04-221-181/+290
| | | | | | | | | | | The new code unrolls the main loop slightly without adding too much overhead and minimizes the comparisons for the search CHAR. Geometric Mean of all benchmarks New / Old: 0.755 See email for all results. Full xcheck passes on x86_64 with and without multiarch enabled. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize {str|wcs}rchr-avx2Noah Goldstein2022-04-221-157/+269
| | | | | | | | | | | The new code unrolls the main loop slightly without adding too much overhead and minimizes the comparisons for the search CHAR. Geometric Mean of all benchmarks New / Old: 0.832 See email for all results. Full xcheck passes on x86_64 with and without multiarch enabled. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize {str|wcs}rchr-sse2Noah Goldstein2022-04-224-444/+339
| | | | | | | | | | | The new code unrolls the main loop slightly without adding too much overhead and minimizes the comparisons for the search CHAR. Geometric Mean of all benchmarks New / Old: 0.741 See email for all results. Full xcheck passes on x86_64 with and without multiarch enabled. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86-64: Fix SSE2 memcmp and SSSE3 memmove for x32H.J. Lu2022-04-222-0/+8
| | | | | | | | | | | | | | | | Clear the upper 32 bits in RDX (memory size) for x32 to fix FAIL: string/tst-size_t-memcmp FAIL: string/tst-size_t-memcmp-2 FAIL: string/tst-size_t-memcpy FAIL: wcsmbs/tst-size_t-wmemcmp on x32 introduced by 8804157ad9 x86: Optimize memcmp SSE2 in memcmp.S 26b2478322 x86: Reduce code size of mem{move|pcpy|cpy}-ssse3 Reviewed-by: Noah Goldstein <goldstein.w.n@gmail.com>
* x86: Fix missing __wmemcmp def for disable-multiarch buildNoah Goldstein2022-04-192-8/+6
| | | | | | | | | | | | | | | | commit 8804157ad9da39631703b92315460808eac86b0c Author: Noah Goldstein <goldstein.w.n@gmail.com> Date: Fri Apr 15 12:27:59 2022 -0500 x86: Optimize memcmp SSE2 in memcmp.S Only defined wmemcmp and missed __wmemcmp. This commit fixes that by defining __wmemcmp and setting wmemcmp as a weak alias to __wmemcmp. Both multiarch and disable-multiarch builds succeed and full xchecks pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Cleanup page cross code in memcmp-avx2-movbe.SNoah Goldstein2022-04-151-37/+61
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Old code was both inefficient and wasted code size. New code (-62 bytes) and comparable or better performance in the page cross case. geometric_mean(N=20) of page cross cases New / Original: 0.960 size, align0, align1, ret, New Time/Old Time 1, 4095, 0, 0, 1.001 1, 4095, 0, 1, 0.999 1, 4095, 0, -1, 1.0 2, 4094, 0, 0, 1.0 2, 4094, 0, 1, 1.0 2, 4094, 0, -1, 1.0 3, 4093, 0, 0, 1.0 3, 4093, 0, 1, 1.0 3, 4093, 0, -1, 1.0 4, 4092, 0, 0, 0.987 4, 4092, 0, 1, 1.0 4, 4092, 0, -1, 1.0 5, 4091, 0, 0, 0.984 5, 4091, 0, 1, 1.002 5, 4091, 0, -1, 1.005 6, 4090, 0, 0, 0.993 6, 4090, 0, 1, 1.001 6, 4090, 0, -1, 1.003 7, 4089, 0, 0, 0.991 7, 4089, 0, 1, 1.0 7, 4089, 0, -1, 1.001 8, 4088, 0, 0, 0.875 8, 4088, 0, 1, 0.881 8, 4088, 0, -1, 0.888 9, 4087, 0, 0, 0.872 9, 4087, 0, 1, 0.879 9, 4087, 0, -1, 0.883 10, 4086, 0, 0, 0.878 10, 4086, 0, 1, 0.886 10, 4086, 0, -1, 0.873 11, 4085, 0, 0, 0.878 11, 4085, 0, 1, 0.881 11, 4085, 0, -1, 0.879 12, 4084, 0, 0, 0.873 12, 4084, 0, 1, 0.889 12, 4084, 0, -1, 0.875 13, 4083, 0, 0, 0.873 13, 4083, 0, 1, 0.863 13, 4083, 0, -1, 0.863 14, 4082, 0, 0, 0.838 14, 4082, 0, 1, 0.869 14, 4082, 0, -1, 0.877 15, 4081, 0, 0, 0.841 15, 4081, 0, 1, 0.869 15, 4081, 0, -1, 0.876 16, 4080, 0, 0, 0.988 16, 4080, 0, 1, 0.99 16, 4080, 0, -1, 0.989 17, 4079, 0, 0, 0.978 17, 4079, 0, 1, 0.981 17, 4079, 0, -1, 0.98 18, 4078, 0, 0, 0.981 18, 4078, 0, 1, 0.98 18, 4078, 0, -1, 0.985 19, 4077, 0, 0, 0.977 19, 4077, 0, 1, 0.979 19, 4077, 0, -1, 0.986 20, 4076, 0, 0, 0.977 20, 4076, 0, 1, 0.986 20, 4076, 0, -1, 0.984 21, 4075, 0, 0, 0.977 21, 4075, 0, 1, 0.983 21, 4075, 0, -1, 0.988 22, 4074, 0, 0, 0.983 22, 4074, 0, 1, 0.994 22, 4074, 0, -1, 0.993 23, 4073, 0, 0, 0.98 23, 4073, 0, 1, 0.992 23, 4073, 0, -1, 0.995 24, 4072, 0, 0, 0.989 24, 4072, 0, 1, 0.989 24, 4072, 0, -1, 0.991 25, 4071, 0, 0, 0.99 25, 4071, 0, 1, 0.999 25, 4071, 0, -1, 0.996 26, 4070, 0, 0, 0.993 26, 4070, 0, 1, 0.995 26, 4070, 0, -1, 0.998 27, 4069, 0, 0, 0.993 27, 4069, 0, 1, 0.999 27, 4069, 0, -1, 1.0 28, 4068, 0, 0, 0.997 28, 4068, 0, 1, 1.0 28, 4068, 0, -1, 0.999 29, 4067, 0, 0, 0.996 29, 4067, 0, 1, 0.999 29, 4067, 0, -1, 0.999 30, 4066, 0, 0, 0.991 30, 4066, 0, 1, 1.001 30, 4066, 0, -1, 0.999 31, 4065, 0, 0, 0.988 31, 4065, 0, 1, 0.998 31, 4065, 0, -1, 0.998 Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove memcmp-sse4.SNoah Goldstein2022-04-154-813/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Code didn't actually use any sse4 instructions since `ptest` was removed in: commit 2f9062d7171850451e6044ef78d91ff8c017b9c0 Author: Noah Goldstein <goldstein.w.n@gmail.com> Date: Wed Nov 10 16:18:56 2021 -0600 x86: Shrink memcmp-sse4.S code size The new memcmp-sse2 implementation is also faster. geometric_mean(N=20) of page cross cases SSE2 / SSE4: 0.905 Note there are two regressions preferring SSE2 for Size = 1 and Size = 65. Size = 1: size, align0, align1, ret, New Time/Old Time 1, 1, 1, 0, 1.2 1, 1, 1, 1, 1.197 1, 1, 1, -1, 1.2 This is intentional. Size == 1 is significantly less hot based on profiles of GCC11 and Python3 than sizes [4, 8] (which is made hotter). Python3 Size = 1 -> 13.64% Python3 Size = [4, 8] -> 60.92% GCC11 Size = 1 -> 1.29% GCC11 Size = [4, 8] -> 33.86% size, align0, align1, ret, New Time/Old Time 4, 4, 4, 0, 0.622 4, 4, 4, 1, 0.797 4, 4, 4, -1, 0.805 5, 5, 5, 0, 0.623 5, 5, 5, 1, 0.777 5, 5, 5, -1, 0.802 6, 6, 6, 0, 0.625 6, 6, 6, 1, 0.813 6, 6, 6, -1, 0.788 7, 7, 7, 0, 0.625 7, 7, 7, 1, 0.799 7, 7, 7, -1, 0.795 8, 8, 8, 0, 0.625 8, 8, 8, 1, 0.848 8, 8, 8, -1, 0.914 9, 9, 9, 0, 0.625 Size = 65: size, align0, align1, ret, New Time/Old Time 65, 0, 0, 0, 1.103 65, 0, 0, 1, 1.216 65, 0, 0, -1, 1.227 65, 65, 0, 0, 1.091 65, 0, 65, 1, 1.19 65, 65, 65, -1, 1.215 This is because A) the checks in range [65, 96] are now unrolled 2x and B) because smaller values <= 16 are now given a hotter path. By contrast the SSE4 version has a branch for Size = 80. The unrolled version has get better performance for returns which need both comparisons. size, align0, align1, ret, New Time/Old Time 128, 4, 8, 0, 0.858 128, 4, 8, 1, 0.879 128, 4, 8, -1, 0.888 As well, out of microbenchmark environments that are not full predictable the branch will have a real-cost. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize memcmp SSE2 in memcmp.SNoah Goldstein2022-04-158-376/+575
| | | | | | | | New code save size (-303 bytes) and has significantly better performance. geometric_mean(N=20) of page cross cases New / Original: 0.634 Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Reduce code size of mem{move|pcpy|cpy}-ssse3Noah Goldstein2022-04-143-3156/+380
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | The goal is to remove most SSSE3 function as SSE4, AVX2, and EVEX are generally preferable. memcpy/memmove is one exception where avoiding unaligned loads with `palignr` is important for some targets. This commit replaces memmove-ssse3 with a better optimized are lower code footprint verion. As well it aliases memcpy to memmove. Aside from this function all other SSSE3 functions should be safe to remove. The performance is not changed drastically although shows overall improvements without any major regressions or gains. bench-memcpy geometric_mean(N=50) New / Original: 0.957 bench-memcpy-random geometric_mean(N=50) New / Original: 0.912 bench-memcpy-large geometric_mean(N=50) New / Original: 0.892 Benchmarks where run on Zhaoxin KX-6840@2000MHz See attached numbers for all results. More important this saves 7246 bytes of code size in memmove an additional 10741 bytes by reusing memmove code for memcpy (total 17987 bytes saves). As well an additional 896 bytes of rodata for the jump table entries.
* x86: Remove mem{move|cpy}-ssse3-backNoah Goldstein2022-04-145-3212/+6
| | | | | | | With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer SSSE3. As a result it is no longer worth it to keep the SSSE3 versions given the code size cost. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove str{p}{n}cpy-ssse3Noah Goldstein2022-04-146-3572/+0
| | | | | | | With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer SSSE3. As a result it is no longer worth it to keep the SSSE3 versions given the code size cost. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove str{n}cat-ssse3Noah Goldstein2022-04-145-879/+0
| | | | | | | With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer SSSE3. As a result it is no longer worth it to keep the SSSE3 versions given the code size cost. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove str{n}{case}cmp-ssse3Noah Goldstein2022-04-1410-202/+30
| | | | | | | With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer SSSE3. As a result it is no longer worth it to keep the SSSE3 versions given the code size cost. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove {w}memcmp-ssse3Noah Goldstein2022-04-145-2006/+0
| | | | | | | With SSE2, SSE4.1, AVX2, and EVEX versions very few targets prefer SSSE3. As a result it is no longer worth it to keep the SSSE3 versions given the code size cost. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove fcopysign{f} implementationAdhemerval Zanella2022-04-073-115/+0
| | | | | | The builtin used by generic code generates similar code. Checked on x86_64-linux-gnu and i686-linux-gnu.
* benchtests: Only build libmvec benchmarks iff $(build-mathvec) is setAdhemerval Zanella2022-04-051-1/+1
| | | | Checked on x86_64-linux-gnu.
* Remove -z combreloc and HAVE_Z_COMBRELOCFangrui Song2022-04-041-16/+2
| | | | | | | | | | | | | -z combreloc has been the default regadless of the architecture since binutils commit f4d733664aabd7bd78c82895e030ec9779a92809 (2002). The configure check added in commit fdde83499a05 (2001) has long been unneeded. We can therefore treat HAVE_Z_COMBRELOC as always 1 and delete dead code paths in dl-machine.h files (many were copied from commit a711b01d34ca and ee0cb67ec238). Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
* x86: Remove fabs{f} implementationAdhemerval Zanella2022-04-042-54/+0
| | | | | For x86_64 is the same as the generic implementation, while for i686 the builtin generates the same code.
* x86: Small improvements for wcslenNoah Goldstein2022-03-281-45/+41
| | | | | | | | | | | | | | Just a few QOL changes. 1. Prefer `add` > `lea` as it has high execution units it can run on. 2. Don't break macro-fusion between `test` and `jcc` 3. Reduce code size by removing gratuitous padding bytes (-90 bytes). geometric_mean(N=20) of all benchmarks New / Original: 0.959 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Small improvements for wcscpy-ssse3Noah Goldstein2022-03-281-97/+97
| | | | | | | | | | | | Just a few small QOL changes. 1. Prefer `add` > `lea` as it has high execution units it can run on. 2. Don't break macro-fusion between `test` and `jcc` geometric_mean(N=20) of all benchmarks New / Original: 0.973 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove AVX str{n}casecmpNoah Goldstein2022-03-256-197/+105
| | | | | | | | | | | | | | | | | The rational is: 1. SSE42 has nearly identical logic so any benefit is minimal (3.4% regression on Tigerlake using SSE42 versus AVX across the benchtest suite). 2. AVX2 version covers the majority of targets that previously prefered it. 3. The targets where AVX would still be best (SnB and IVB) are becoming outdated. All in all the saving the code size is worth it. All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Add EVEX optimized str{n}casecmpNoah Goldstein2022-03-256-40/+321
| | | | | | | geometric_mean(N=40) of all benchmarks EVEX / SSE42: .621 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Add AVX2 optimized str{n}casecmpNoah Goldstein2022-03-258-31/+331
| | | | | | | geometric_mean(N=40) of all benchmarks AVX2 / SSE42: .702 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize str{n}casecmp TOLOWER logic in strcmp-sse42.SNoah Goldstein2022-03-251-48/+35
| | | | | | | | | | | | | Slightly faster method of doing TOLOWER that saves an instruction. Also replace the hard coded 5-byte no with .p2align 4. On builds with CET enabled this misaligned entry to strcasecmp. geometric_mean(N=40) of all benchmarks New / Original: .920 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize str{n}casecmp TOLOWER logic in strcmp.SNoah Goldstein2022-03-251-35/+29
| | | | | | | | | | | | | Slightly faster method of doing TOLOWER that saves an instruction. Also replace the hard coded 5-byte no with .p2align 4. On builds with CET enabled this misaligned entry to strcasecmp. geometric_mean(N=40) of all benchmarks New / Original: .894 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Fix fallback for wcsncmp_avx2 in strcmp-avx2.S [BZ #28896]Noah Goldstein2022-03-251-1/+1
| | | | | | | | | | | | | | | | | | | | Overflow case for __wcsncmp_avx2_rtm should be __wcscmp_avx2_rtm not __wcscmp_avx2. commit ddf0992cf57a93200e0c782e2a94d0733a5a0b87 Author: Noah Goldstein <goldstein.w.n@gmail.com> Date: Sun Jan 9 16:02:21 2022 -0600 x86: Fix __wcsncmp_avx2 in strcmp-avx2.S [BZ# 28755] Set the wrong fallback function for `__wcsncmp_avx2_rtm`. It was set to fallback on to `__wcscmp_avx2` instead of `__wcscmp_avx2_rtm` which can cause spurious aborts. This change will need to be backported. All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove strspn-sse2.S and use the generic implementationNoah Goldstein2022-03-252-116/+4
| | | | | | | | | The generic implementation is faster. geometric_mean(N=20) of all benchmarks New / Original: .710 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove strpbrk-sse2.S and use the generic implementationNoah Goldstein2022-03-252-8/+4
| | | | | | | The generic implementation is faster (see strcspn commit). All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Remove strcspn-sse2.S and use the generic implementationNoah Goldstein2022-03-252-123/+4
| | | | | | | | | The generic implementation is faster. geometric_mean(N=20) of all benchmarks New / Original: .678 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize strspn in strspn-c.cNoah Goldstein2022-03-251-47/+39
| | | | | | | | | | | | Use _mm_cmpeq_epi8 and _mm_movemask_epi8 to get strlen instead of _mm_cmpistri. Also change offset to unsigned to avoid unnecessary sign extensions. geometric_mean(N=20) of all benchmarks that dont fallback on sse2; New / Original: .901 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Optimize strcspn and strpbrk in strcspn-c.cNoah Goldstein2022-03-251-46/+37
| | | | | | | | | | | | Use _mm_cmpeq_epi8 and _mm_movemask_epi8 to get strlen instead of _mm_cmpistri. Also change offset to unsigned to avoid unnecessary sign extensions. geometric_mean(N=20) of all benchmarks that dont fallback on sse2/strlen; New / Original: .928 All string/memory tests pass. Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
* x86: Code cleanup in strchr-evex and comment justifying branchNoah Goldstein2022-03-251-66/+80
| | | | | | | | | | | Small code cleanup for size: -81 bytes. Add comment justifying using a branch to do NULL/non-null return. All string/memory tests pass and no regressions in benchtests. geometric_mean(N=20) of all benchmarks New / Original: .985 Reviewed-by: H.J. Lu <hjl.tools@gmail.com>
generated by cgit-pink 1.4.1 (git 2.36.1) at 2024-11-01 14:18:36 +0000