[runtime] Initialize thread suspend policy at startup, inline getter (mono/mono#16149)

* [runtime] Initialize thread suspend policy at startup, inline getter

On some benchmarks we saw mono_threads_suspend_policy() using a lot of CPU
time.

Rather than doing an init-on-first-use, initialize the policy once upfront when
the JIT it starting up and make the getter method static inline.

* move mono_threads_suspend_policy_init into mono_thread_info_init

* [mini] Initialize suspend policy for `mono --version`

Need to initialize the suspend policy before printing its name.  Otherwise the
suspend policy is unset since no other runtime initialization is done for `--version`.

Commit migrated from https://github.com/mono/mono/commit/592de53a1f687d115fef86978e56a7fe7b4340c2

diff --git a/src/mono/mono/mini/driver.c b/src/mono/mono/mini/driver.c
index 44933a6..be595c3 100644 (file)
--- a/src/mono/mono/mini/driver.c
+++ b/src/mono/mono/mini/driver.c
@@ -1677,6 +1677,7 @@ mono_get_version_info (void)
 #endif
 #endif
 
+       mono_threads_suspend_policy_init ();
        g_string_append_printf (output, "\tSuspend:       %s\n", mono_threads_suspend_policy_name (mono_threads_suspend_policy ()));
 
        return g_string_free (output, FALSE);

diff --git a/src/mono/mono/utils/mono-threads-coop.c b/src/mono/mono/utils/mono-threads-coop.c
index 3e22e7f..90b8575 100644 (file)
--- a/src/mono/mono/utils/mono-threads-coop.c
+++ b/src/mono/mono/utils/mono-threads-coop.c
@@ -652,13 +652,13 @@ threads_suspend_policy_getenv (void)
        return policy;
 }
 
-static char threads_suspend_policy;
+char mono_threads_suspend_policy_hidden_dont_modify;
 
-MonoThreadsSuspendPolicy
-mono_threads_suspend_policy (void)
+void
+mono_threads_suspend_policy_init (void)
 {
-       int policy = threads_suspend_policy;
-       if (G_UNLIKELY (policy == 0)) {
+       int policy = 0;
+       {
                // thread suspend policy:
                // if the MONO_THREADS_SUSPEND env is set, use it.
                // otherwise if there's a compiled-in default, use it.
@@ -675,9 +675,8 @@ mono_threads_suspend_policy (void)
                W32_RESTORE_LAST_ERROR_FROM_RESTORE_POINT;
 
                g_assert (policy);
-               threads_suspend_policy = (char)policy;
+               mono_threads_suspend_policy_hidden_dont_modify = (char)policy;
        }
-       return (MonoThreadsSuspendPolicy)policy;
 }
 
 static MonoThreadsSuspendPolicy
@@ -703,7 +702,7 @@ mono_threads_suspend_validate_policy (MonoThreadsSuspendPolicy policy)
 void
 mono_threads_suspend_override_policy (MonoThreadsSuspendPolicy new_policy)
 {
-       threads_suspend_policy = (char)mono_threads_suspend_validate_policy (new_policy);
+       mono_threads_suspend_policy_hidden_dont_modify = (char)mono_threads_suspend_validate_policy (new_policy);
        g_warning ("Overriding suspend policy.  Using %s suspend.", mono_threads_suspend_policy_name (mono_threads_suspend_policy ()));
 }
 

diff --git a/src/mono/mono/utils/mono-threads-coop.h b/src/mono/mono/utils/mono-threads-coop.h
index c4fbde7..5bb65c4 100644 (file)
--- a/src/mono/mono/utils/mono-threads-coop.h
+++ b/src/mono/mono/utils/mono-threads-coop.h
@@ -69,8 +69,15 @@ mono_threads_suspend_policy_is_multiphase_stw_enabled (MonoThreadsSuspendPolicy
 gboolean
 mono_threads_suspend_policy_is_blocking_transition_enabled (MonoThreadsSuspendPolicy p);
 
-MonoThreadsSuspendPolicy
-mono_threads_suspend_policy (void) MONO_LLVM_INTERNAL;
+extern char mono_threads_suspend_policy_hidden_dont_modify MONO_LLVM_INTERNAL;
+
+static inline MonoThreadsSuspendPolicy
+mono_threads_suspend_policy (void) {
+       return (MonoThreadsSuspendPolicy)mono_threads_suspend_policy_hidden_dont_modify;
+}
+
+void
+mono_threads_suspend_policy_init (void);
 
 const char*
 mono_threads_suspend_policy_name (MonoThreadsSuspendPolicy p);

diff --git a/src/mono/mono/utils/mono-threads.c b/src/mono/mono/utils/mono-threads.c
index f2e45d8..5561296 100644 (file)
--- a/src/mono/mono/utils/mono-threads.c
+++ b/src/mono/mono/utils/mono-threads.c
@@ -900,6 +900,9 @@ mono_thread_info_init (size_t info_size)
        gboolean res;
        thread_info_size = info_size;
        char *sleepLimit;
+
+       mono_threads_suspend_policy_init ();
+
 #ifdef HOST_WIN32
        res = mono_native_tls_alloc (&thread_info_key, NULL);
        res = mono_native_tls_alloc (&thread_exited_key, NULL);