Change ZMQ_THREAD_AFFINITY to…

Change ZMQ_THREAD_AFFINITY to ZMQ_THREAD_AFFINITY_CPU_ADD/ZMQ_THREAD_AFFINITY_CPU_REMOVE. Avoid prefix thread names when no prefix was set.

doc/zmq_ctx_set.txt

@@ -76,15 +76,25 @@ This option only applies before creating any sockets on the context.
 Default value:: -1
 
 
-ZMQ_THREAD_AFFINITY: Set CPU affinity for I/O threads
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-The 'ZMQ_THREAD_AFFINITY' argument sets CPU affinity for the internal
+ZMQ_THREAD_AFFINITY_CPU_ADD: Add a CPU to list of affinity for I/O threads
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The 'ZMQ_THREAD_AFFINITY_CPU_ADD' argument adds a specific CPU to the affinity list for the internal
 context's thread pool. This option is only supported on Linux.
-On Linux, each bit of the 'option_value' argument will represent an enabled
-CPU in the corresponding cpu_set_t; for example the value 0x1 will set affinity
-of all context's thread pool to CPU 0; the value 0x110 will set affinity
-of all context's thread pool to CPU 1 and 2.
 This option only applies before creating any sockets on the context.
+The default affinity list is empty and means that no explicit CPU-affinity will be set on
+internal context's threads.
+
+[horizontal]
+Default value:: -1
+
+
+ZMQ_THREAD_AFFINITY_CPU_REMOVE: Remove a CPU to list of affinity for I/O threads
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+The 'ZMQ_THREAD_AFFINITY_CPU_REMOVE' argument removes a specific CPU to the affinity list for the internal
+context's thread pool. This option is only supported on Linux.
+This option only applies before creating any sockets on the context.
+The default affinity list is empty and means that no explicit CPU-affinity will be set on
+internal context's threads.
 
 [horizontal]
 Default value:: -1

include/zmq.h

@@ -610,9 +610,9 @@ ZMQ_EXPORT void zmq_threadclose (void* thread);
 
 /*  DRAFT Context options                                                     */
 #define ZMQ_MSG_T_SIZE 6
-#define ZMQ_THREAD_AFFINITY 7
-#define ZMQ_THREAD_AFFINITY_DFLT -1
-#define ZMQ_THREAD_NAME_PREFIX 8
+#define ZMQ_THREAD_AFFINITY_CPU_ADD 7
+#define ZMQ_THREAD_AFFINITY_CPU_REMOVE 8
+#define ZMQ_THREAD_NAME_PREFIX 9
 
 /*  DRAFT Socket methods.                                                     */
 ZMQ_EXPORT int zmq_join (void *s, const char *group);

src/ctx.cpp

@@ -77,8 +77,7 @@ zmq::ctx_t::ctx_t () :
     blocky (true),
     ipv6 (false),
     thread_priority (ZMQ_THREAD_PRIORITY_DFLT),
-    thread_sched_policy (ZMQ_THREAD_SCHED_POLICY_DFLT),
-    thread_affinity (ZMQ_THREAD_AFFINITY_DFLT)
+    thread_sched_policy (ZMQ_THREAD_SCHED_POLICY_DFLT)
 {
 #ifdef HAVE_FORK
     pid = getpid();
@@ -252,9 +251,20 @@ int zmq::ctx_t::set (int option_, int optval_)
         thread_sched_policy = optval_;
     }
     else
-    if (option_ == ZMQ_THREAD_AFFINITY && optval_ >= 0) {
+    if (option_ == ZMQ_THREAD_AFFINITY_CPU_ADD && optval_ >= 0) {
         scoped_lock_t locker(opt_sync);
-        thread_affinity = optval_;
+        thread_affinity_cpus.insert( optval_ );
+    }
+    else
+    if (option_ == ZMQ_THREAD_AFFINITY_CPU_REMOVE && optval_ >= 0) {
+        scoped_lock_t locker(opt_sync);
+        std::set<int>::iterator it = thread_affinity_cpus.find( optval_ );
+        if (it != thread_affinity_cpus.end()) {
+            thread_affinity_cpus.erase( it );
+        } else {
+            errno = EINVAL;
+            rc = -1;
+        }
     }
     else
     if (option_ == ZMQ_THREAD_NAME_PREFIX && optval_ >= 0) {
@@ -411,11 +421,13 @@ void zmq::ctx_t::start_thread (thread_t &thread_, thread_fn *tfn_, void *arg_) c
 {
     static unsigned int nthreads_started = 0;
 
-    thread_.setSchedulingParameters(thread_priority, thread_sched_policy, thread_affinity);
+    thread_.setSchedulingParameters(thread_priority, thread_sched_policy, thread_affinity_cpus);
     thread_.start(tfn_, arg_);
 #ifndef ZMQ_HAVE_ANDROID
     std::ostringstream s;
-    s << thread_name_prefix << "/ZMQbg/" << nthreads_started;
+    if (!thread_name_prefix.empty())
+        s << thread_name_prefix << "/";
+    s << "ZMQbg/" << nthreads_started;
     thread_.setThreadName (s.str().c_str());
 #endif
     nthreads_started++;

src/ctx.hpp

@@ -214,7 +214,7 @@ namespace zmq
         //  Thread parameters.
         int thread_priority;
         int thread_sched_policy;
-        int thread_affinity;
+        std::set<int> thread_affinity_cpus;
         std::string thread_name_prefix;
 
         //  Synchronisation of access to context options.

src/thread.cpp

@@ -70,12 +70,12 @@ void zmq::thread_t::stop ()
     win_assert (rc2 != 0);
 }
 
-void zmq::thread_t::setSchedulingParameters(int priority_, int schedulingPolicy_, int affinity_)
+void zmq::thread_t::setSchedulingParameters(int priority_, int schedulingPolicy_, const std::set<int>& affinity_cpus_)
 {
     // not implemented
     LIBZMQ_UNUSED (priority_);
     LIBZMQ_UNUSED (schedulingPolicy_);
-    LIBZMQ_UNUSED (affinity_);
+    LIBZMQ_UNUSED (affinity_cpus_);
 }
 
 void zmq::thread_t::setThreadName(const char *name_)
@@ -125,11 +125,11 @@ void zmq::thread_t::stop ()
     posix_assert (rc);
 }
 
-void zmq::thread_t::setSchedulingParameters(int priority_, int schedulingPolicy_, int affinity_)
+void zmq::thread_t::setSchedulingParameters(int priority_, int schedulingPolicy_, const std::set<int>& affinity_cpus_)
 {
     thread_priority=priority_;
     thread_sched_policy=schedulingPolicy_;
-    thread_affinity=affinity_;
+    thread_affinity_cpus=affinity_cpus_;
 }
 
 void zmq::thread_t::applySchedulingParameters()         // to be called in secondary thread context
@@ -194,15 +194,13 @@ void zmq::thread_t::applySchedulingParameters()         // to be called in secon
     }
 
 #ifdef ZMQ_HAVE_PTHREAD_SET_AFFINITY
-    if (thread_affinity != ZMQ_THREAD_AFFINITY_DFLT)
+    if (!thread_affinity_cpus.empty())
     {
         cpu_set_t cpuset;
         CPU_ZERO(&cpuset);
-        for (unsigned int cpuidx=0; cpuidx<sizeof(int)*8; cpuidx++)
+        for (std::set<int>::const_iterator it = thread_affinity_cpus.begin(); it != thread_affinity_cpus.end(); it++)
         {
-            int cpubit = (1 << cpuidx);
-            if ( (thread_affinity & cpubit) != 0 )
-                CPU_SET( cpuidx , &cpuset );
+            CPU_SET( (int)(*it) , &cpuset );
         }
         rc = pthread_setaffinity_np(pthread_self(), sizeof(cpu_set_t), &cpuset);
         posix_assert (rc);

src/thread.hpp

@@ -33,6 +33,7 @@
 #ifndef ZMQ_HAVE_WINDOWS
 #include <pthread.h>
 #endif
+#include <set>
 
 namespace zmq
 {
@@ -55,7 +56,6 @@ namespace zmq
             , arg(NULL)
             , thread_priority(ZMQ_THREAD_PRIORITY_DFLT)
             , thread_sched_policy(ZMQ_THREAD_SCHED_POLICY_DFLT)
-            , thread_affinity(ZMQ_THREAD_AFFINITY_DFLT)
         {
         }
 
@@ -68,7 +68,7 @@ namespace zmq
 
         // Sets the thread scheduling parameters. Only implemented for
         // pthread. Has no effect on other platforms.
-        void setSchedulingParameters(int priority_, int schedulingPolicy_, int affinity_);
+        void setSchedulingParameters(int priority_, int schedulingPolicy_, const std::set<int>& affinity_cpus_);
 
         // Sets the thread name, 16 characters max including terminating NUL.
         // Only implemented for pthread. Has no effect on other platforms.
@@ -91,7 +91,7 @@ namespace zmq
         //  Thread scheduling parameters.
         int thread_priority;
         int thread_sched_policy;
-        int thread_affinity;
+        std::set<int> thread_affinity_cpus;
 
         thread_t (const thread_t&);
         const thread_t &operator = (const thread_t&);

src/zmq_draft.h

@@ -91,9 +91,9 @@
 
 /*  DRAFT Context options                                                     */
 #define ZMQ_MSG_T_SIZE 6
-#define ZMQ_THREAD_AFFINITY 7
-#define ZMQ_THREAD_AFFINITY_DFLT -1
-#define ZMQ_THREAD_NAME_PREFIX 8
+#define ZMQ_THREAD_AFFINITY_CPU_ADD 7
+#define ZMQ_THREAD_AFFINITY_CPU_REMOVE 8
+#define ZMQ_THREAD_NAME_PREFIX 9
 
 /*  DRAFT Socket methods.                                                     */
 int zmq_join (void *s, const char *group);

tests/test_ctx_options.cpp

@@ -81,10 +81,6 @@ void test_ctx_thread_opts(void* ctx)
     assert (rc == -1 && errno == EINVAL);
     rc = zmq_ctx_set(ctx, ZMQ_THREAD_PRIORITY, ZMQ_THREAD_PRIORITY_DFLT);
     assert (rc == -1 && errno == EINVAL);
-#ifdef ZMQ_THREAD_AFFINITY
-    rc = zmq_ctx_set(ctx, ZMQ_THREAD_AFFINITY, ZMQ_THREAD_AFFINITY_DFLT);
-    assert (rc == -1 && errno == EINVAL);
-#endif
 
 
     // test scheduling policy:
@@ -113,16 +109,27 @@ void test_ctx_thread_opts(void* ctx)
     }
 
 
-#ifdef ZMQ_THREAD_AFFINITY
+#ifdef ZMQ_THREAD_AFFINITY_CPU_ADD
     // test affinity:
 
-    int cpu_affinity_test = (1 << 0);
      // this should result in background threads being placed only on the
      // first CPU available on this system; try experimenting with other values
-         // (e.g., 1<<5 to use CPU index 5) and use "top -H" or "taskset -pc" to see the result
+     // (e.g., 5 to use CPU index 5) and use "top -H" or "taskset -pc" to see the result
+
+    int cpus_add[] = { 0, 1 };
+    for (unsigned int idx=0; idx < sizeof(cpus_add)/sizeof(cpus_add[0]); idx++)
+    {
+        rc = zmq_ctx_set(ctx, ZMQ_THREAD_AFFINITY_CPU_ADD, cpus_add[idx]);
+        assert (rc == 0);
+    }
 
-    rc = zmq_ctx_set(ctx, ZMQ_THREAD_AFFINITY, cpu_affinity_test);
+    // you can also remove CPUs from list of affinities:
+    int cpus_remove[] = { 1 };
+    for (unsigned int idx=0; idx < sizeof(cpus_remove)/sizeof(cpus_remove[0]); idx++)
+    {
+        rc = zmq_ctx_set(ctx, ZMQ_THREAD_AFFINITY_CPU_REMOVE, cpus_remove[idx]);
         assert (rc == 0);
+    }
 #endif