From 4e2d1790529a416ea6b28d6f619b33d44625c5fc Mon Sep 17 00:00:00 2001
From: Julian Kunkel <JulianKunkel@users.noreply.github.com>
Date: Mon, 3 Aug 2020 12:30:21 +0100
Subject: [PATCH] Detection of system features for number of sockets #245
 (#246)

* Configure checks for architecture-specific functions to detect nr of sockets. #245
---
 configure.ac    | 24 ++++++++++++++++++++++++
 src/ior.c       |  3 +--
 src/utilities.c | 24 ++++++++++++++++++------
 3 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/configure.ac b/configure.ac
index dc05ee7..1253b51 100755
--- a/configure.ac
+++ b/configure.ac
@@ -400,6 +400,30 @@ Consider --with-aws4c=, CPPFLAGS, LDFLAGS, etc])
             LDFLAGS=$ORIG_LDFLAGS
 ])
 
+# Check for existence of the function to detect the CPU socket ID (for multi-socket systems)
+AC_COMPILE_IFELSE(
+  [AC_LANG_SOURCE([[
+      int main(){
+      unsigned long a,d,c;
+      __asm__ volatile("rdtscp" : "=a" (a), "=d" (d), "=c" (c));
+      return 0;
+      }
+  ]])],
+  AC_DEFINE([HAVE_RDTSCP_ASM], [], [Has ASM to detect CPU socket ID]))
+
+AC_COMPILE_IFELSE(
+  [AC_LANG_SOURCE([[
+      #define _GNU_SOURCE
+      #include <unistd.h>
+      #include <sys/syscall.h>
+      unsigned long GetProcessorAndCore(int *chip, int *core){
+      	return syscall(SYS_getcpu, core, chip, NULL);
+      }
+      int main(){
+      }
+  ]])],
+  AC_DEFINE([HAVE_GETCPU_SYSCALL], [], [Has syscall to detect CPU socket ID]))
+
 
 # Enable building "IOR", in all capitals
 AC_ARG_ENABLE([caps],
diff --git a/src/ior.c b/src/ior.c
index c220ae0..196f6ec 100755
--- a/src/ior.c
+++ b/src/ior.c
@@ -792,8 +792,7 @@ void GetTestFileName(char *testFileName, IOR_param_t * test)
         strcpy(initialTestFileName, test->testFileName);
         if(test->dualMount){
                 GetProcessorAndCore(&socket, &core);
-                sprintf(tmpString, "%s%d/%s",initialTestFileName,
-                        socket, "data");
+                sprintf(tmpString, "%s%d/%s",initialTestFileName, socket, "data");
                 strcpy(initialTestFileName, tmpString);
         }
         fileNames = ParseFileName(initialTestFileName, &count);
diff --git a/src/utilities.c b/src/utilities.c
index 5b65e55..36db9c9 100755
--- a/src/utilities.c
+++ b/src/utilities.c
@@ -16,6 +16,12 @@
 #  include "config.h"
 #endif
 
+#ifdef HAVE_GETCPU_SYSCALL
+#  define _GNU_SOURCE
+#  include <unistd.h>
+#  include <sys/syscall.h>
+#endif
+
 #ifdef __linux__
 #  define _GNU_SOURCE            /* Needed for O_DIRECT in fcntl */
 #endif                           /* __linux__ */
@@ -869,17 +875,15 @@ char *HumanReadable(IOR_offset_t value, int base)
         return valueStr;
 }
 
-#if defined(__aarch64__)
-// TODO: This might be general enough to provide the functionality for any system
-// regardless of processor type given we aren't worried about thread/process migration.
+#if defined(HAVE_GETCPU_SYSCALL)
+// Assume we aren't worried about thread/process migration.
 // Test on Intel systems and see if we can get rid of the architecture specificity
 // of the code.
 unsigned long GetProcessorAndCore(int *chip, int *core){
 	return syscall(SYS_getcpu, core, chip, NULL);
 }
-// TODO: Add in AMD function
-#else
-// If we're not on an ARM processor assume we're on an intel processor and use the
+#elif defined(HAVE_RDTSCP_ASM)
+// We're on an intel processor and use the
 // rdtscp instruction.
 unsigned long GetProcessorAndCore(int *chip, int *core){
 	unsigned long a,d,c;
@@ -888,4 +892,12 @@ unsigned long GetProcessorAndCore(int *chip, int *core){
 	*core = c & 0xFFF;
 	return ((unsigned long)a) | (((unsigned long)d) << 32);;
 }
+#else
+// TODO: Add in AMD function
+unsigned long GetProcessorAndCore(int *chip, int *core){
+#warning GetProcessorAndCore is implemented as a dummy
+  *chip = 0;
+  *core = 0;
+	return 1;
+}
 #endif