base: Use M5_UNLIKELY with conditional DPRINTF family functions.

Most DPRINTFs will be skipped over most of the time, and when they
aren't they'll already have overhead from string handling, output to the
console and/or a file, etc, which will drown out the behavior of a
branch.

Change-Id: I5475d7b5add63b44f60c0a1d46b4b14e6bf30fd3
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/34818
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>

diff --git a/src/base/trace.hh b/src/base/trace.hh
index 3d8752cfc941dc1df0a138e0edbc763e2bc1227e..aafb9c8e434f5b31028403d3c8dce0297d82f45e 100644 (file)
--- a/src/base/trace.hh
+++ b/src/base/trace.hh
@@ -182,14 +182,14 @@ class Named
 
 #define DDUMP(x, data, count) do {               \
     using namespace Debug;                       \
-    if (DTRACE(x))                               \
+    if (M5_UNLIKELY(DTRACE(x)))                  \
         Trace::getDebugLogger()->dump(           \
             curTick(), name(), data, count, #x); \
 } while (0)
 
 #define DPRINTF(x, ...) do {                     \
     using namespace Debug;                       \
-    if (DTRACE(x)) {                             \
+    if (M5_UNLIKELY(DTRACE(x))) {                \
         Trace::getDebugLogger()->dprintf_flag(   \
             curTick(), name(), #x, __VA_ARGS__); \
     }                                            \
@@ -197,7 +197,7 @@ class Named
 
 #define DPRINTFS(x, s, ...) do {                        \
     using namespace Debug;                              \
-    if (DTRACE(x)) {                                    \
+    if (M5_UNLIKELY(DTRACE(x))) {                       \
         Trace::getDebugLogger()->dprintf_flag(          \
                 curTick(), s->name(), #x, __VA_ARGS__); \
     }                                                   \
@@ -205,7 +205,7 @@ class Named
 
 #define DPRINTFR(x, ...) do {                          \
     using namespace Debug;                             \
-    if (DTRACE(x)) {                                   \
+    if (M5_UNLIKELY(DTRACE(x))) {                      \
         Trace::getDebugLogger()->dprintf_flag(         \
             (Tick)-1, std::string(), #x, __VA_ARGS__); \
     }                                                  \