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[Qemu-devel] [PATCH v4 14/14] hardfloat: support float32/64 comparison
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From: |
Emilio G. Cota |
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Subject: |
[Qemu-devel] [PATCH v4 14/14] hardfloat: support float32/64 comparison |
|
Date: |
Mon, 11 Jun 2018 21:49:00 -0400 |
Performance results for fp-bench:
1. Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
- before:
cmp-single: 113.01 MFlops
cmp-double: 115.54 MFlops
- after:
cmp-single: 527.83 MFlops
cmp-double: 457.21 MFlops
2. ARM Aarch64 A57 @ 2.4GHz
- before:
cmp-single: 39.32 MFlops
cmp-double: 39.80 MFlops
- after:
cmp-single: 162.74 MFlops
cmp-double: 167.08 MFlops
3. IBM POWER8E @ 2.1 GHz
- before:
cmp-single: 60.81 MFlops
cmp-double: 62.76 MFlops
- after:
cmp-single: 235.39 MFlops
cmp-double: 283.44 MFlops
Here using float{32,64}_is_any_nan is faster than using isnan
for all machines. On x86_64 the perf difference is just a few
percentage points, but on aarch64 we go from 117/119 to
164/169 MFlops for single/double precision, respectively.
Aggregate performance improvement for the last few patches:
[ all charts in png: https://imgur.com/a/4yV8p ]
1. Host: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
qemu-aarch64 NBench score; higher is better
Host: Intel(R) Core(TM) i7-6700K CPU @ 4.00GHz
16 +-+-----------+-------------+----===-------+---===-------+-----------+-+
14 +-+..........................@@@&&.=.......@@@&&.=...................+-+
12 address@hidden@.&address@hidden@.&.=.....+befor=== +-+
10 address@hidden@.&address@hidden@.&.=.....+ad@@&& = +-+
8 address@hidden&address@hidden@.&.=.....+ @@u& = +-+
6 +-+............@@@&&address@hidden&address@hidden&address@hidden& = +-+
4 address@hidden&address@hidden&address@hidden&.=+**.#+$ address@hidden& =
+-+
2 address@hidden&address@hidden&address@hidden&.=.**.#+$+sqr& = +-+
0 +-+-----***##$%%@@&&=-***##$$%@@&&==***##$$%@@&&==-**##$$%+cmp==-----+-+
FOURIER NEURAL NELU DECOMPOSITION gmean
qemu-aarch64 SPEC06fp (test set) speedup over
QEMU 4c2c1015905
Host: Intel(R) Core(TM) i7-6700K CPU @
4.00GHz
error bars: 95% confidence interval
4.5
+-+---+-----+----+-----+-----+-&---+-----+----+-----+-----+-----+----+-----+-----+-----+-----+----+-----+---+-+
4
+-+..........................+@@+...........................................................................+-+
3.5
+-+..............%%@&.........@@..............%%@&............................................+++dsub
+-+
2.5
+-+....&&+.......%%@&address@hidden&+..@@&+.%%@&....................................+%%&+.+%@&++%%@&
+-+
2
+-+..+%%&..+%@&+.%%@&address@hidden&.+$$@&..%%@&..%%@&.......+%%&+.%%@&+......+%%@&.+%%&++$$@&++d%@&
%%@&+-+
1.5
+-+**#$%&**#$@&**#%@&address@hidden@**#$%&**#$@&**$%@&address@hidden@**#$%&**#%@&**$%@&address@hidden&**#$@&*+f%@&**$%@&+-+
0.5
+-+**#$%&**#$@&**#%@&address@hidden@**#$%&**#$@&**$%@&address@hidden@**#$%&**#%@&**$%@&address@hidden&**#$@&+sqr@&**$%@&+-+
0
+-+**#$%&**#$@&**#%@&address@hidden@**#$%&**#$@&**$%@&address@hidden@**#$%&**#%@&**$%@&address@hidden&**#$@&*+cmp&**$%@&+-+
410.bw416.gam433.434.z435.436.cac437.lesli444.447.de450.so453454.ca459.GemsF465.tont470.lb4482.sphinxgeomean
2. Host: ARM Aarch64 A57 @ 2.4GHz
qemu-aarch64 NBench score; higher is better
Host: Applied Micro X-Gene, Aarch64 A57 @ 2.4 GHz
5 +-+-----------+-------------+-------------+-------------+-----------+-+
4.5 +-+........................................@@@&==...................+-+
3 4 +-+..........................@@@&address@hidden@&.=.....+before +-+
3 address@hidden@&address@hidden@&.=.....+ad@@@&== +-+
2.5 +-+.....................##$$%%.@&address@hidden@&.=.....+ @m@& = +-+
2 +-+............@@@&==.***#.$.%.@&.=.***#$$%%.@&.=.***#$$%%d@& = +-+
1.5 +-+.....***#$$%%.@&.=.*.*#.$.%.@&.=.*.*#.$.%.@&.=.*.*#+$ +f@& = +-+
0.5 +-+.....*.*#.$.%.@&.=.*.*#.$.%.@&.=.*.*#.$.%.@&.=.*.*#+$+sqr& = +-+
0 +-+-----***#$$%%@@&==-***#$$%%@@&==-***#$$%%@@&==-***#$$%+cmp==-----+-+
FOURIER NEURAL NLU DECOMPOSITION gmean
Note that by not inlining the soft-fp primitives we end up
with a smaller softfloat.o--in particular, see the difference
for the softfloat.o built for fp-bench:
- before this series:
text data bss dec hex filename
103235 0 0 103235 19343 softfloat.o
- after:
text data bss dec hex filename
93369 0 0 93369 16cb9 softfloat.o
Signed-off-by: Emilio G. Cota <address@hidden>
---
fpu/softfloat.c | 74 ++++++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 60 insertions(+), 14 deletions(-)
diff --git a/fpu/softfloat.c b/fpu/softfloat.c
index f89e872..1cf74d1 100644
--- a/fpu/softfloat.c
+++ b/fpu/softfloat.c
@@ -2671,28 +2671,74 @@ static int compare_floats(FloatParts a, FloatParts b,
bool is_quiet,
}
}
-#define COMPARE(sz) \
-int float ## sz ## _compare(float ## sz a, float ## sz b, \
- float_status *s) \
+#define COMPARE(name, attr, sz) \
+static int attr \
+name(float ## sz a, float ## sz b, bool is_quiet, float_status *s) \
{ \
FloatParts pa = float ## sz ## _unpack_canonical(a, s); \
FloatParts pb = float ## sz ## _unpack_canonical(b, s); \
- return compare_floats(pa, pb, false, s); \
-} \
-int float ## sz ## _compare_quiet(float ## sz a, float ## sz b, \
- float_status *s) \
-{ \
- FloatParts pa = float ## sz ## _unpack_canonical(a, s); \
- FloatParts pb = float ## sz ## _unpack_canonical(b, s); \
- return compare_floats(pa, pb, true, s); \
+ return compare_floats(pa, pb, is_quiet, s); \
}
-COMPARE(16)
-COMPARE(32)
-COMPARE(64)
+COMPARE(soft_float16_compare, , 16)
+COMPARE(soft_float32_compare, QEMU_SOFTFLOAT_ATTR, 32)
+COMPARE(soft_float64_compare, QEMU_SOFTFLOAT_ATTR, 64)
#undef COMPARE
+int __attribute__((flatten))
+float16_compare(float16 a, float16 b, float_status *s)
+{
+ return soft_float16_compare(a, b, false, s);
+}
+
+int __attribute__((flatten))
+float16_compare_quiet(float16 a, float16 b, float_status *s)
+{
+ return soft_float16_compare(a, b, true, s);
+}
+
+#define GEN_FPU_COMPARE(name, quiet_name, soft_t, host_t) \
+ static int \
+ fpu_ ## name(soft_t a, soft_t b, bool is_quiet, float_status *s) \
+ { \
+ host_t ha, hb; \
+ \
+ if (QEMU_NO_HARDFLOAT) { \
+ return soft_ ## name(a, b, is_quiet, s); \
+ } \
+ soft_t ## _input_flush2(&a, &b, s); \
+ ha = soft_t ## _to_ ## host_t(a); \
+ hb = soft_t ## _to_ ## host_t(b); \
+ if (unlikely(soft_t ## _is_any_nan(a) || \
+ soft_t ## _is_any_nan(b))) { \
+ return soft_ ## name(a, b, is_quiet, s); \
+ } \
+ if (isgreater(ha, hb)) { \
+ return float_relation_greater; \
+ } \
+ if (isless(ha, hb)) { \
+ return float_relation_less; \
+ } \
+ return float_relation_equal; \
+ } \
+ \
+ int __attribute__((flatten)) \
+ name(soft_t a, soft_t b, float_status *s) \
+ { \
+ return fpu_ ## name(a, b, false, s); \
+ } \
+ \
+ int __attribute__((flatten)) \
+ quiet_name(soft_t a, soft_t b, float_status *s) \
+ { \
+ return fpu_ ## name(a, b, true, s); \
+ }
+
+GEN_FPU_COMPARE(float32_compare, float32_compare_quiet, float32, float)
+GEN_FPU_COMPARE(float64_compare, float64_compare_quiet, float64, double)
+#undef GEN_FPU_COMPARE
+
/* Multiply A by 2 raised to the power N. */
static FloatParts scalbn_decomposed(FloatParts a, int n, float_status *s)
{
--
2.7.4
- [Qemu-devel] [PATCH v4 00/14] fp-test + hardfloat, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 07/14] softfloat: add float{32, 64}_is_zero_or_normal, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 06/14] softfloat: rename canonicalize to sf_canonicalize, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 09/14] hardfloat: support float32/64 addition and subtraction, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 11/14] hardfloat: support float32/64 division, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 05/14] tests/fp: add fp-bench, a collection of simple floating point microbenchmarks, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 01/14] tests: add fp-test, a floating point test suite, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 03/14] softfloat: add float{32, 64}_is_{de, }normal, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 04/14] target/tricore: use float32_is_denormal, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 14/14] hardfloat: support float32/64 comparison,
Emilio G. Cota <=
- [Qemu-devel] [PATCH v4 13/14] hardfloat: support float32/64 square root, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 12/14] hardfloat: support float32/64 fused multiply-add, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 02/14] fp-test: add muladd variants, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 08/14] fpu: introduce hardfloat, Emilio G. Cota, 2018/06/11
- [Qemu-devel] [PATCH v4 10/14] hardfloat: support float32/64 multiplication, Emilio G. Cota, 2018/06/11
- Re: [Qemu-devel] [PATCH v4 00/14] fp-test + hardfloat, no-reply, 2018/06/12