From 34b94adc4b6dbbffd4a15fad7fdccfb65c4d1f45 Mon Sep 17 00:00:00 2001
From: Manish Godse <61718172+mangod9@users.noreply.github.com>
Date: Fri, 28 Aug 2020 12:35:34 -0700
Subject: [PATCH 1/4] Fix reading cpu cache size for Alpine(musl)

---
 src/coreclr/src/gc/unix/gcenv.unix.cpp   |  7 ++++++-
 src/coreclr/src/pal/src/misc/sysinfo.cpp | 11 ++++++++---
 2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/src/coreclr/src/gc/unix/gcenv.unix.cpp b/src/coreclr/src/gc/unix/gcenv.unix.cpp
index 8bcc98a3526aee..049b328de5b9ef 100644
--- a/src/coreclr/src/gc/unix/gcenv.unix.cpp
+++ b/src/coreclr/src/gc/unix/gcenv.unix.cpp
@@ -834,9 +834,13 @@ static size_t GetLogicalProcessorCacheSizeFromOS()
     cacheSize = std::max(cacheSize, ( size_t) sysconf(_SC_LEVEL4_CACHE_SIZE));
 #endif
 
-#if defined(HOST_ARM64)
     if (cacheSize == 0)
     {
+        //
+        // Fallback to retrieve cachesize via /sys/.. if sysconf was not available 
+        // for the platform. Currently musl and arm64 should be only cases to use  
+        // this method to determine cache size.
+        // 
         size_t size;
 
         if (ReadMemoryValueFromFile("/sys/devices/system/cpu/cpu0/cache/index0/size", &size))
@@ -851,6 +855,7 @@ static size_t GetLogicalProcessorCacheSizeFromOS()
             cacheSize = std::max(cacheSize, size);
     }
 
+#if defined(HOST_ARM64)
     if (cacheSize == 0)
     {
         // It is currently expected to be missing cache size info
diff --git a/src/coreclr/src/pal/src/misc/sysinfo.cpp b/src/coreclr/src/pal/src/misc/sysinfo.cpp
index 4592aa2a14342c..6e75b20a645ce2 100644
--- a/src/coreclr/src/pal/src/misc/sysinfo.cpp
+++ b/src/coreclr/src/pal/src/misc/sysinfo.cpp
@@ -565,9 +565,13 @@ PAL_GetLogicalProcessorCacheSizeFromOS()
     cacheSize = std::max(cacheSize, (size_t)sysconf(_SC_LEVEL4_CACHE_SIZE));
 #endif
 
-#if defined(HOST_ARM64)
-    if(cacheSize == 0)
+    if (cacheSize == 0)
     {
+        //
+        // Fallback to retrieve cachesize via /sys/.. if sysconf was not available 
+        // for the platform. Currently musl and arm64 should be only cases to use  
+        // this method to determine cache size.
+        // 
         size_t size;
 
         if(ReadMemoryValueFromFile("/sys/devices/system/cpu/cpu0/cache/index0/size", &size))
@@ -582,7 +586,8 @@ PAL_GetLogicalProcessorCacheSizeFromOS()
             cacheSize = std::max(cacheSize, size);
     }
 
-    if(cacheSize == 0)
+#if defined(HOST_ARM64)
+    if (cacheSize == 0)
     {
         // It is currently expected to be missing cache size info
         //

From 4371e43e4a57cfe31efb0bc4e532318f624de4ec Mon Sep 17 00:00:00 2001
From: Manish Godse <61718172+mangod9@users.noreply.github.com>
Date: Fri, 28 Aug 2020 14:25:43 -0700
Subject: [PATCH 2/4] limiting the fallback to Linux only

---
 src/coreclr/src/gc/unix/gcenv.unix.cpp   | 2 ++
 src/coreclr/src/pal/src/misc/sysinfo.cpp | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/src/coreclr/src/gc/unix/gcenv.unix.cpp b/src/coreclr/src/gc/unix/gcenv.unix.cpp
index 049b328de5b9ef..bb60ec6a501623 100644
--- a/src/coreclr/src/gc/unix/gcenv.unix.cpp
+++ b/src/coreclr/src/gc/unix/gcenv.unix.cpp
@@ -834,6 +834,7 @@ static size_t GetLogicalProcessorCacheSizeFromOS()
     cacheSize = std::max(cacheSize, ( size_t) sysconf(_SC_LEVEL4_CACHE_SIZE));
 #endif
 
+#if defined(TARGET_LINUX)
     if (cacheSize == 0)
     {
         //
@@ -854,6 +855,7 @@ static size_t GetLogicalProcessorCacheSizeFromOS()
         if (ReadMemoryValueFromFile("/sys/devices/system/cpu/cpu0/cache/index4/size", &size))
             cacheSize = std::max(cacheSize, size);
     }
+#endif
 
 #if defined(HOST_ARM64)
     if (cacheSize == 0)
diff --git a/src/coreclr/src/pal/src/misc/sysinfo.cpp b/src/coreclr/src/pal/src/misc/sysinfo.cpp
index 6e75b20a645ce2..d63c80ca82585b 100644
--- a/src/coreclr/src/pal/src/misc/sysinfo.cpp
+++ b/src/coreclr/src/pal/src/misc/sysinfo.cpp
@@ -565,6 +565,7 @@ PAL_GetLogicalProcessorCacheSizeFromOS()
     cacheSize = std::max(cacheSize, (size_t)sysconf(_SC_LEVEL4_CACHE_SIZE));
 #endif
 
+#if defined(TARGET_LINUX)
     if (cacheSize == 0)
     {
         //
@@ -585,6 +586,7 @@ PAL_GetLogicalProcessorCacheSizeFromOS()
         if(ReadMemoryValueFromFile("/sys/devices/system/cpu/cpu0/cache/index4/size", &size))
             cacheSize = std::max(cacheSize, size);
     }
+#endif
 
 #if defined(HOST_ARM64)
     if (cacheSize == 0)

From 3a5deed57116c4a365a87b315dfc434f6b6dc4d9 Mon Sep 17 00:00:00 2001
From: Manish Godse <61718172+mangod9@users.noreply.github.com>
Date: Fri, 28 Aug 2020 16:03:22 -0700
Subject: [PATCH 3/4] exclude ARM

---
 src/coreclr/src/gc/unix/gcenv.unix.cpp   | 2 +-
 src/coreclr/src/pal/src/misc/sysinfo.cpp | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/coreclr/src/gc/unix/gcenv.unix.cpp b/src/coreclr/src/gc/unix/gcenv.unix.cpp
index bb60ec6a501623..978c5b9e862946 100644
--- a/src/coreclr/src/gc/unix/gcenv.unix.cpp
+++ b/src/coreclr/src/gc/unix/gcenv.unix.cpp
@@ -857,7 +857,7 @@ static size_t GetLogicalProcessorCacheSizeFromOS()
     }
 #endif
 
-#if defined(HOST_ARM64)
+#if defined(TARGET_LINUX) && !defined(HOST_ARM)
     if (cacheSize == 0)
     {
         // It is currently expected to be missing cache size info
diff --git a/src/coreclr/src/pal/src/misc/sysinfo.cpp b/src/coreclr/src/pal/src/misc/sysinfo.cpp
index d63c80ca82585b..6b23c17ac14820 100644
--- a/src/coreclr/src/pal/src/misc/sysinfo.cpp
+++ b/src/coreclr/src/pal/src/misc/sysinfo.cpp
@@ -565,7 +565,7 @@ PAL_GetLogicalProcessorCacheSizeFromOS()
     cacheSize = std::max(cacheSize, (size_t)sysconf(_SC_LEVEL4_CACHE_SIZE));
 #endif
 
-#if defined(TARGET_LINUX)
+#if defined(TARGET_LINUX) && !defined(HOST_ARM)
     if (cacheSize == 0)
     {
         //

From d9da30eae0bca0c816a5b29c8e3ab25399a1ba5c Mon Sep 17 00:00:00 2001
From: Manish Godse <61718172+mangod9@users.noreply.github.com>
Date: Fri, 28 Aug 2020 16:54:36 -0700
Subject: [PATCH 4/4] fixing copy-paste error

---
 src/coreclr/src/gc/unix/gcenv.unix.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/src/coreclr/src/gc/unix/gcenv.unix.cpp b/src/coreclr/src/gc/unix/gcenv.unix.cpp
index 978c5b9e862946..fcba54551a8ded 100644
--- a/src/coreclr/src/gc/unix/gcenv.unix.cpp
+++ b/src/coreclr/src/gc/unix/gcenv.unix.cpp
@@ -834,7 +834,7 @@ static size_t GetLogicalProcessorCacheSizeFromOS()
     cacheSize = std::max(cacheSize, ( size_t) sysconf(_SC_LEVEL4_CACHE_SIZE));
 #endif
 
-#if defined(TARGET_LINUX)
+#if defined(TARGET_LINUX) && !defined(HOST_ARM)
     if (cacheSize == 0)
     {
         //
@@ -857,7 +857,7 @@ static size_t GetLogicalProcessorCacheSizeFromOS()
     }
 #endif
 
-#if defined(TARGET_LINUX) && !defined(HOST_ARM)
+#if defined(HOST_ARM64)
     if (cacheSize == 0)
     {
         // It is currently expected to be missing cache size info