From 3ff10baa68f565a8a4fcec18216090f12cd73625 Mon Sep 17 00:00:00 2001
From: FritzFlorian <flo.fritz@t-online.de>
Date: Tue, 16 Apr 2019 11:54:11 +0200
Subject: [PATCH] Add try_lock method to spin_lock implementations.

---
 lib/pls/include/pls/internal/base/tas_spin_lock.h  |  2 +-
 lib/pls/include/pls/internal/base/ttas_spin_lock.h |  6 ++----
 lib/pls/include/pls/internal/helpers/profiler.h    |  5 +++++
 lib/pls/src/internal/base/tas_spin_lock.cpp        | 11 +++++++++--
 lib/pls/src/internal/base/ttas_spin_lock.cpp       | 17 +++++++++++++++--
 5 files changed, 32 insertions(+), 9 deletions(-)

diff --git a/lib/pls/include/pls/internal/base/tas_spin_lock.h b/lib/pls/include/pls/internal/base/tas_spin_lock.h
index 173ee76..17db757 100644
--- a/lib/pls/include/pls/internal/base/tas_spin_lock.h
+++ b/lib/pls/include/pls/internal/base/tas_spin_lock.h
@@ -28,7 +28,7 @@ namespace pls {
                 tas_spin_lock(const tas_spin_lock& other): flag_{ATOMIC_FLAG_INIT}, yield_at_tries_{other.yield_at_tries_} {}
 
                 void lock();
-                bool try_lock();
+                bool try_lock(unsigned int num_tries=1);
                 void unlock();
             };
         }
diff --git a/lib/pls/include/pls/internal/base/ttas_spin_lock.h b/lib/pls/include/pls/internal/base/ttas_spin_lock.h
index 821865e..592c847 100644
--- a/lib/pls/include/pls/internal/base/ttas_spin_lock.h
+++ b/lib/pls/include/pls/internal/base/ttas_spin_lock.h
@@ -2,8 +2,6 @@
 #ifndef PLS_TTAS_SPIN_LOCK_H
 #define PLS_TTAS_SPIN_LOCK_H
 
-#include "tas_spin_lock.h"
-
 #include <atomic>
 #include <iostream>
 
@@ -20,7 +18,7 @@ namespace pls {
              */
             class ttas_spin_lock {
                 std::atomic<int> flag_;
-                unsigned int yield_at_tries_;
+                const unsigned int yield_at_tries_;
 
 
             public:
@@ -28,7 +26,7 @@ namespace pls {
                 ttas_spin_lock(const ttas_spin_lock& other): flag_{0}, yield_at_tries_{other.yield_at_tries_} {}
 
                 void lock();
-                bool try_lock();
+                bool try_lock(unsigned int num_tries=1);
                 void unlock();
             };
         }
diff --git a/lib/pls/include/pls/internal/helpers/profiler.h b/lib/pls/include/pls/internal/helpers/profiler.h
index 221994d..2902344 100644
--- a/lib/pls/include/pls/internal/helpers/profiler.h
+++ b/lib/pls/include/pls/internal/helpers/profiler.h
@@ -4,6 +4,7 @@
 #ifdef ENABLE_EASY_PROFILER
 
 #include <easy/profiler.h>
+#include <easy/arbitrary_value.h>
 
 #define PROFILE_WORK_BLOCK(msg) EASY_BLOCK(msg, profiler::colors::LightGreen)
 #define PROFILE_FORK_JOIN_STEALING(msg) EASY_BLOCK(msg, profiler::colors::LightBlue)
@@ -16,6 +17,8 @@
 #define PROFILE_ENABLE EASY_PROFILER_ENABLE
 #define PROFILE_MAIN_THREAD EASY_MAIN_THREAD
 
+#define PROFILE_VALUE(name, value) EASY_VALUE(name, value)
+
 #else //ENABLE_EASY_PROFILER
 
 #define PROFILE_WORK_BLOCK(msg)
@@ -29,5 +32,7 @@
 #define PROFILE_ENABLE
 #define PROFILE_MAIN_THREAD
 
+#define PROFILE_VALUE(name, value)
+
 #endif //ENABLE_EASY_PROFILER
 #endif //PLS_PROFILER_H
diff --git a/lib/pls/src/internal/base/tas_spin_lock.cpp b/lib/pls/src/internal/base/tas_spin_lock.cpp
index 3ad4e42..e6f9d1e 100644
--- a/lib/pls/src/internal/base/tas_spin_lock.cpp
+++ b/lib/pls/src/internal/base/tas_spin_lock.cpp
@@ -15,8 +15,15 @@ namespace pls {
                 }
             }
 
-            bool tas_spin_lock::try_lock() {
-                return flag_.test_and_set(std::memory_order_acquire) == 0;
+            bool tas_spin_lock::try_lock(unsigned int num_tries) {
+                PROFILE_LOCK("Try Acquire Lock")
+                while (flag_.test_and_set(std::memory_order_acquire)) {
+                    num_tries--;
+                    if (num_tries <= 0) {
+                        return false;
+                    }
+                }
+                return true;
             }
 
             void tas_spin_lock::unlock() {
diff --git a/lib/pls/src/internal/base/ttas_spin_lock.cpp b/lib/pls/src/internal/base/ttas_spin_lock.cpp
index b60934b..e2c8bff 100644
--- a/lib/pls/src/internal/base/ttas_spin_lock.cpp
+++ b/lib/pls/src/internal/base/ttas_spin_lock.cpp
@@ -21,9 +21,22 @@ namespace pls {
                 } while (!flag_.compare_exchange_weak(expected, 1, std::memory_order_acquire));
             }
 
-            bool ttas_spin_lock::try_lock() {
+            bool ttas_spin_lock::try_lock(unsigned int num_tries) {
+                PROFILE_LOCK("Try Acquire Lock")
                 int expected = 0;
-                return flag_.load(std::memory_order_relaxed) == 0 && flag_.compare_exchange_weak(expected, 1, std::memory_order_acquire);
+
+                do {
+                    while (flag_.load(std::memory_order_relaxed) == 1) {
+                        num_tries--;
+                        if (num_tries <= 0) {
+                            return false;
+                        }
+                    }
+
+                    expected = 0;
+                } while (!flag_.compare_exchange_weak(expected, 1, std::memory_order_acquire));
+
+                return true;
             }
 
             void ttas_spin_lock::unlock() {
--
libgit2 0.26.0