[19/30] x86_64: Add glibc-hwcaps support

Message ID 6b56704d61b2fddf9e03eb5d0781d0fff57db96a.1592836143.git.fweimer@redhat.com
State New
Headers show
Series
  • RFC: elf: glibc-hwcaps support
Related show

Commit Message

Adhemerval Zanella via Libc-alpha June 22, 2020, 3:14 p.m.
Details of the supported CPU flags and the names are still subject to
changes.
---
 sysdeps/x86_64/dl-hwcaps-subdirs.c | 73 ++++++++++++++++++++++++++++++
 1 file changed, 73 insertions(+)
 create mode 100644 sysdeps/x86_64/dl-hwcaps-subdirs.c

-- 
2.25.4

Comments

Adhemerval Zanella via Libc-alpha June 25, 2020, 10:13 a.m. | #1
* Florian Weimer via Libc-alpha:

> Details of the supported CPU flags and the names are still subject to

> changes.

> +int32_t

> +_dl_hwcaps_subdirs_active (void)

> +{

> +  const struct cpu_features *cpu_features = __get_cpu_features ();

> +  int32_t result = 0;

> +  int32_t bit = 1 << 3;

> +

> +  /* Test in reverse preference order.  */

> +

> +  /* x86-100.  */

> +  if (!(CPU_FEATURES_ARCH_P (cpu_features, CMPXCHG16B_Usable)

> +        && CPU_FEATURES_ARCH_P (cpu_features, POPCNT_Usable)

> +        && CPU_FEATURES_ARCH_P (cpu_features, SSE3_Usable)

> +        && CPU_FEATURES_ARCH_P (cpu_features, SSE4_1_Usable)

> +        && CPU_FEATURES_ARCH_P (cpu_features, SSE4_2_Usable)

> +        && CPU_FEATURES_ARCH_P (cpu_features, SSSE3_Usable)))

> +    return result;


This misuses CPU_FEATURES_ARCH_P, and the recent <cpu-features.h> update
on the master branch makes it finally fail to compile.  The version
below should fix the build and also correct the feature detection logic.

Thanks,
Florian

diff --git a/sysdeps/x86_64/dl-hwcaps-subdirs.c b/sysdeps/x86_64/dl-hwcaps-subdirs.c
new file mode 100644
index 0000000000..1a90854b69
--- /dev/null
+++ b/sysdeps/x86_64/dl-hwcaps-subdirs.c
@@ -0,0 +1,73 @@
+/* Architecture-specific glibc-hwcaps subdirectories.  x86 version.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dl-hwcaps.h>
+#include <cpu-features.h>
+
+const char _dl_hwcaps_subdirs[] = "x86-103:x86-102:x86-101:x86-100";
+
+int32_t
+_dl_hwcaps_subdirs_active (void)
+{
+  const struct cpu_features *cpu_features = __get_cpu_features ();
+  int32_t result = 0;
+  int32_t bit = 1 << 3;
+
+  /* Test in reverse preference order.  */
+
+  /* x86-100.  */
+  if (!(CPU_FEATURES_CPU_P (cpu_features, CMPXCHG16B)
+        && CPU_FEATURES_CPU_P (cpu_features, POPCNT)
+        && CPU_FEATURES_CPU_P (cpu_features, SSE3)
+        && CPU_FEATURES_CPU_P (cpu_features, SSE4_1)
+        && CPU_FEATURES_CPU_P (cpu_features, SSE4_2)
+        && CPU_FEATURES_CPU_P (cpu_features, SSSE3)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+  /* x86-101.  */
+  if (!(CPU_FEATURES_ARCH_P (cpu_features, AVX_Usable)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+  /* x86-102.  */
+  if (!(CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable)
+        && CPU_FEATURES_CPU_P (cpu_features, BMI1)
+        && CPU_FEATURES_CPU_P (cpu_features, BMI2)
+        && CPU_FEATURES_ARCH_P (cpu_features, F16C_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, FMA_Usable)
+        && CPU_FEATURES_CPU_P (cpu_features, LZCNT)
+        && CPU_FEATURES_CPU_P (cpu_features, MOVBE)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+ /* x86-103.  */
+  if (!(CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512BW)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512CD)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512DQ)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512VL)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+  return result;
+}
Adhemerval Zanella via Libc-alpha June 25, 2020, 1:50 p.m. | #2
On Thu, Jun 25, 2020 at 3:14 AM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>

> * Florian Weimer via Libc-alpha:

>

> > Details of the supported CPU flags and the names are still subject to

> > changes.

> > +int32_t

> > +_dl_hwcaps_subdirs_active (void)

> > +{

> > +  const struct cpu_features *cpu_features = __get_cpu_features ();

> > +  int32_t result = 0;

> > +  int32_t bit = 1 << 3;

> > +

> > +  /* Test in reverse preference order.  */

> > +

> > +  /* x86-100.  */

> > +  if (!(CPU_FEATURES_ARCH_P (cpu_features, CMPXCHG16B_Usable)

> > +        && CPU_FEATURES_ARCH_P (cpu_features, POPCNT_Usable)

> > +        && CPU_FEATURES_ARCH_P (cpu_features, SSE3_Usable)

> > +        && CPU_FEATURES_ARCH_P (cpu_features, SSE4_1_Usable)

> > +        && CPU_FEATURES_ARCH_P (cpu_features, SSE4_2_Usable)

> > +        && CPU_FEATURES_ARCH_P (cpu_features, SSSE3_Usable)))

> > +    return result;

>

> This misuses CPU_FEATURES_ARCH_P, and the recent <cpu-features.h> update

> on the master branch makes it finally fail to compile.  The version

> below should fix the build and also correct the feature detection logic.

>

> Thanks,

> Florian

>

> diff --git a/sysdeps/x86_64/dl-hwcaps-subdirs.c b/sysdeps/x86_64/dl-hwcaps-subdirs.c

> new file mode 100644

> index 0000000000..1a90854b69

> --- /dev/null

> +++ b/sysdeps/x86_64/dl-hwcaps-subdirs.c

> @@ -0,0 +1,73 @@

> +/* Architecture-specific glibc-hwcaps subdirectories.  x86 version.

> +   Copyright (C) 2020 Free Software Foundation, Inc.

> +   This file is part of the GNU C Library.

> +

> +   The GNU C Library is free software; you can redistribute it and/or

> +   modify it under the terms of the GNU Lesser General Public

> +   License as published by the Free Software Foundation; either

> +   version 2.1 of the License, or (at your option) any later version.

> +

> +   The GNU C Library is distributed in the hope that it will be useful,

> +   but WITHOUT ANY WARRANTY; without even the implied warranty of

> +   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

> +   Lesser General Public License for more details.

> +

> +   You should have received a copy of the GNU Lesser General Public

> +   License along with the GNU C Library; if not, see

> +   <https://www.gnu.org/licenses/>.  */

> +

> +#include <dl-hwcaps.h>

> +#include <cpu-features.h>

> +

> +const char _dl_hwcaps_subdirs[] = "x86-103:x86-102:x86-101:x86-100";

>


I understand why you use digits.  But it is very cryptic.  Since it is
user visible,
how can one tell what 103 means without looking at glibc source?

-- 
H.J.

Patch

diff --git a/sysdeps/x86_64/dl-hwcaps-subdirs.c b/sysdeps/x86_64/dl-hwcaps-subdirs.c
new file mode 100644
index 0000000000..4a8fae976e
--- /dev/null
+++ b/sysdeps/x86_64/dl-hwcaps-subdirs.c
@@ -0,0 +1,73 @@ 
+/* Architecture-specific glibc-hwcaps subdirectories.  x86 version.
+   Copyright (C) 2020 Free Software Foundation, Inc.
+   This file is part of the GNU C Library.
+
+   The GNU C Library is free software; you can redistribute it and/or
+   modify it under the terms of the GNU Lesser General Public
+   License as published by the Free Software Foundation; either
+   version 2.1 of the License, or (at your option) any later version.
+
+   The GNU C Library is distributed in the hope that it will be useful,
+   but WITHOUT ANY WARRANTY; without even the implied warranty of
+   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+   Lesser General Public License for more details.
+
+   You should have received a copy of the GNU Lesser General Public
+   License along with the GNU C Library; if not, see
+   <https://www.gnu.org/licenses/>.  */
+
+#include <dl-hwcaps.h>
+#include <cpu-features.h>
+
+const char _dl_hwcaps_subdirs[] = "x86-103:x86-102:x86-101:x86-100";
+
+int32_t
+_dl_hwcaps_subdirs_active (void)
+{
+  const struct cpu_features *cpu_features = __get_cpu_features ();
+  int32_t result = 0;
+  int32_t bit = 1 << 3;
+
+  /* Test in reverse preference order.  */
+
+  /* x86-100.  */
+  if (!(CPU_FEATURES_ARCH_P (cpu_features, CMPXCHG16B_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, POPCNT_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, SSE3_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, SSE4_1_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, SSE4_2_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, SSSE3_Usable)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+  /* x86-101.  */
+  if (!(CPU_FEATURES_ARCH_P (cpu_features, AVX_Usable)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+  /* x86-102.  */
+  if (!(CPU_FEATURES_ARCH_P (cpu_features, AVX2_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, BMI1_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, BMI2_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, F16C_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, FMA_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, LZCNT_Usable)
+        && CPU_FEATURES_ARCH_P (cpu_features, MOVBE_Usable)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+ /* x86-103.  */
+  if (!(CPU_FEATURES_ARCH_P (cpu_features, AVX512F_Usable)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512BW)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512CD)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512DQ)
+        && CPU_FEATURES_CPU_P (cpu_features, AVX512VL)))
+    return result;
+  result |= bit;
+  bit >>= 1;
+
+  return result;
+}