Avoid cpuid instructions in cache info discovery.

When multiarch is enabled we have this information stored.  Use it.

diff --git a/ChangeLog b/ChangeLog
index 29e4468..f0a6675 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,9 @@
 2009-07-23  Ulrich Drepper  <drepper@redhat.com>
 
+       * sysdeps/x86_64/cacheinfo.c [USE_MULTIARCH]: Rearrange code to
+       avoid additional cpuid instructions.  Most of the information is
+       stored somewhere.
+
        * sysdeps/unix/sysv/linux/i386/sysconf.c (intel_02_known): Add more
        cache descriptors.
        * sysdeps/x86_64/cacheinfo.c (intel_02_known): Likewise.

diff --git a/sysdeps/x86_64/cacheinfo.c b/sysdeps/x86_64/cacheinfo.c
index 0793909..75b8195 100644 (file)
--- a/sysdeps/x86_64/cacheinfo.c
+++ b/sysdeps/x86_64/cacheinfo.c
@@ -25,6 +25,17 @@
 
 #ifdef USE_MULTIARCH
 # include "multiarch/init-arch.h"
+
+# define is_intel __cpu_features.kind == arch_kind_intel
+# define is_amd __cpu_features.kind == arch_kind_amd
+# define max_cpuid __cpu_features.max_cpuid
+#else
+  /* This spells out "GenuineIntel".  */
+# define is_intel \
+  ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69
+  /* This spells out "AuthenticAMD".  */
+# define is_amd \
+  ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65
 #endif
 
 static const struct intel_02_cache_info
@@ -155,6 +166,12 @@ intel_check_word (int name, unsigned int value, bool *has_level_2,
              /* Intel reused this value.  For family 15, model 6 it
                 specifies the 3rd level cache.  Otherwise the 2nd
                 level cache.  */
+             unsigned int family;
+             unsigned int model;
+#ifdef USE_MULTIARCH
+             family = __cpu_features.family;
+             model = __cpu_features.model;
+#else
              unsigned int eax;
              unsigned int ebx;
              unsigned int ecx;
@@ -163,9 +180,10 @@ intel_check_word (int name, unsigned int value, bool *has_level_2,
                            : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
                            : "0" (1));
 
-             unsigned int family = ((eax >> 20) & 0xff) + ((eax >> 8) & 0xf);
-             unsigned int model = ((((eax >>16) & 0xf) << 4)
-                                   + ((eax >> 4) & 0xf));
+             family = ((eax >> 20) & 0xff) + ((eax >> 8) & 0xf);
+             model = (((eax >>16) & 0xf) << 4) + ((eax >> 4) & 0xf);
+#endif
+
              if (family == 15 && model == 6)
                {
                  /* The level 3 cache is encoded for this model like
@@ -397,21 +415,24 @@ long int
 attribute_hidden
 __cache_sysconf (int name)
 {
+#ifdef USE_MULTIARCH
+  if (__cpu_features.kind == arch_kind_unknown)
+    __init_cpu_features ();
+#else
   /* Find out what brand of processor.  */
-  unsigned int eax;
+  unsigned int max_cpuid;
   unsigned int ebx;
   unsigned int ecx;
   unsigned int edx;
   asm volatile ("cpuid"
-               : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx)
+               : "=a" (max_cpuid), "=b" (ebx), "=c" (ecx), "=d" (edx)
                : "0" (0));
+#endif
 
-  /* This spells out "GenuineIntel".  */
-  if (ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69)
-    return handle_intel (name, eax);
+  if (is_intel)
+    return handle_intel (name, max_cpuid);
 
-  /* This spells out "AuthenticAMD".  */
-  if (ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65)
+  if (is_amd)
     return handle_amd (name);
 
   // XXX Fill in more vendors.
@@ -460,20 +481,11 @@ init_cacheinfo (void)
 #ifdef USE_MULTIARCH
   if (__cpu_features.kind == arch_kind_unknown)
     __init_cpu_features ();
-# define is_intel __cpu_features.kind == arch_kind_intel
-# define is_amd __cpu_features.kind == arch_kind_amd
-# define max_cpuid __cpu_features.max_cpuid
 #else
   int max_cpuid;
   asm volatile ("cpuid"
                : "=a" (max_cpuid), "=b" (ebx), "=c" (ecx), "=d" (edx)
                : "0" (0));
-  /* This spells out "GenuineIntel".  */
-# define is_intel \
-  ebx == 0x756e6547 && ecx == 0x6c65746e && edx == 0x49656e69
-  /* This spells out "AuthenticAMD".  */
-# define is_amd \
-  ebx == 0x68747541 && ecx == 0x444d4163 && edx == 0x69746e65
 #endif
 
   if (is_intel)