powerpc: hypot refactor and optimization

System Internals / glibc - Adhemerval Zanella [linaro.org] - 8 July 2019 20:21 EDT

The powerpc hypot is slight optimized by:

- Commit 8df4e219e43, both isnan and isinf are always inlined and thus the check TEST_INF_NAN does not make sense anymore. The generic check for POWER7 should be faster on all powerpc configuration.

- The redundant check 'y > two60factor && (x / y) > two60' is removed.

Both changes leads to unrequired ifunc especialization for power7 and thus they are removed. Finally The code is also cleanup a bit by inlining the constants floating points.

The performance changes using the hypot benchtests are:

- POWER9 without patch: "hypot": { "overflow": { "duration": 4.98585e+09, "iterations": 4.84932e+08, "max": 46.551, "min": 10.229, "mean": 10.2815 }, "higher_two500": { "duration": 5.00192e+09, "iterations": 4.24843e+08, "max": 33.319, "min": 11.606, "mean": 11.7736 }, "subnormal": { "duration": 5.0075e+09, "iterations": 4.06792e+08, "max": 22.178, "min": 12.15, "mean": 12.3097 }, "less_two500": { "duration": 5.00685e+09, "iterations": 4.08772e+08, "max": 22.784, "min": 12.052, "mean": 12.2485 }, "default": { "duration": 5.06002e+09, "iterations": 4.09894e+08, "max": 20.648, "min": 11.874, "mean": 12.3447 } }

- POWER9 with patch: "hypot": { "overflow": { "duration": 4.91848e+09, "iterations": 7.28039e+08, "max": 47.958, "min": 6.436, "mean": 6.75579 }, "higher_two500": { "duration": 4.9359e+09, "iterations": 6.63376e+08, "max": 20.783, "min": 7.321, "mean": 7.44057 }, "subnormal": { "duration": 4.9479e+09, "iterations": 6.19772e+08, "max": 18.856, "min": 7.817, "mean": 7.98341 }, "less_two500": { "duration": 4.94275e+09, "iterations": 6.3889e+08, "max": 17.452, "min": 7.597, "mean": 7.73647 }, "default": { "duration": 5.03645e+09, "iterations": 5.70718e+08, "max": 18.904, "min": 8.55, "mean": 8.82476 } }

- POWER7 without patch "hypot": { "overflow": { "duration": 4.86637e+09, "iterations": 6.43196e+08, "max": 53.958, "min": 7.328, "mean": 7.56592 }, "higher_two500": { "duration": 4.99842e+09, "iterations": 3.11012e+08, "max": 78.227, "min": 15.696, "mean": 16.0715 }, "subnormal": { "duration": 4.99841e+09, "iterations": 3.08935e+08, "max": 51.392, "min": 15.983, "mean": 16.1795 }, "less_two500": { "duration": 5.00108e+09, "iterations": 2.99464e+08, "max": 73.247, "min": 16.416, "mean": 16.7001 }, "default": { "duration": 5.04645e+09, "iterations": 3.52608e+08, "max": 70.073, "min": 13.38, "mean": 14.3118 } }

- POWER7 with patch "hypot": { "overflow": { "duration": 4.80785e+09, "iterations": 8.00001e+08, "max": 66.262, "min": 5.888, "mean": 6.00981 }, "higher_two500": { "duration": 4.9859e+09, "iterations": 3.39449e+08, "max": 5148.44, "min": 14.539, "mean": 14.6882 }, "subnormal": { "duration": 4.9905e+09, "iterations": 3.28874e+08, "max": 64.905, "min": 14.971, "mean": 15.1745 }, "less_two500": { "duration": 4.99494e+09, "iterations": 3.19755e+08, "max": 103.696, "min": 14.972, "mean": 15.6211 }, "default": { "duration": 5.03951e+09, "iterations": 4.02502e+08, "max": 61.008, "min": 12.368, "mean": 12.5205 } }

Checked on powerpc-linux-gnu (built without --with-cpu, with--with-cpu=power4 and with --with-cpu=power5+ and --disable-multi-arch), powerpc64-linux-gnu (built without --with-cp and with --with-cpu=power5+ and --disable-multi-arch).

- sysdeps/powerpc/fpu/e_hypot.c (two60, two500, two600, two1022, twoM500, twoM600, two60factor, pdnum): Remove. (TEST_INFO_NAN, GET_TW0_HIGH_WORD): Remove macro. (__ieee754_hypot): Replace static variables with inline definition, remove ununsed branches.
- sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile (libm-sysdep_routines): Remove e_hypot-* objects. (CFLAGS-e_hypot-power7.c, CFLAGS-e_hypotf-power7.c): Remove rule.
- sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot-power7.c: Remove file.
- sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot-ppc64.c: Likewise.
- sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot.c: Likewise.
- sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf-power7.c: Likewise.
- sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf-ppc64.c: Likewise.
- sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf.c: Likewise.

69461d9896 powerpc: hypot refactor and optimization
ChangeLog | 16 ++++
sysdeps/powerpc/fpu/e_hypot.c | 94 +++++-----------------
sysdeps/powerpc/powerpc64/fpu/multiarch/Makefile | 5 +-
.../powerpc64/fpu/multiarch/e_hypot-power7.c | 19 -----
.../powerpc64/fpu/multiarch/e_hypot-ppc64.c | 26 ------
sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypot.c | 33 --------
.../powerpc64/fpu/multiarch/e_hypotf-power7.c | 19 -----
.../powerpc64/fpu/multiarch/e_hypotf-ppc64.c | 26 ------
sysdeps/powerpc/powerpc64/fpu/multiarch/e_hypotf.c | 33 --------
9 files changed, 39 insertions(+), 232 deletions(-)

Upstream: sourceware.org


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