Keep objects in cache between tasks (ray-project#29)

* fix caching behavior

* fixes

src/common/common.c

@@ -6,6 +6,9 @@
 #include <sys/stat.h>
 #include <fcntl.h>
 
+/* This is used to define the array of object IDs. */
+const UT_icd object_id_icd = {sizeof(object_id), NULL, NULL, NULL};
+
 const unique_id NIL_ID = {{255, 255, 255, 255, 255, 255, 255, 255, 255, 255,
                            255, 255, 255, 255, 255, 255, 255, 255, 255, 255}};
 

src/common/common.h

@@ -8,6 +8,8 @@
 #include <inttypes.h>
 #include <execinfo.h>
 
+#include "utarray.h"
+
 #ifndef RAY_COMMON_DEBUG
 #define LOG_DEBUG(M, ...)
 #else
@@ -51,6 +53,8 @@ CHECK(COND)
 
 typedef struct { unsigned char id[UNIQUE_ID_SIZE]; } unique_id;
 
+extern const UT_icd object_id_icd;
+
 extern const unique_id NIL_ID;
 
 /* Generate a globally unique ID. */

src/common/thirdparty/utringbuffer.h

@@ -0,0 +1,108 @@
+/*
+Copyright (c) 2008-2016, Troy D. Hanson   http://troydhanson.github.com/uthash/
+All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
+IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
+TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A
+PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER
+OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
+EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
+PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
+PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
+LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
+NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+*/
+
+/* a ring-buffer implementation using macros
+ */
+#ifndef UTRINGBUFFER_H
+#define UTRINGBUFFER_H
+
+#define UTRINGBUFFER_VERSION 2.0.1
+
+#include <stdlib.h>
+#include <string.h>
+#include "utarray.h"  // for "UT_icd"
+
+typedef struct {
+    unsigned i;       /* index of next available slot; wraps at n */
+    unsigned n;       /* capacity */
+    unsigned char f;  /* full */
+    UT_icd icd;       /* initializer, copy and destructor functions */
+    char *d;          /* n slots of size icd->sz */
+} UT_ringbuffer;
+
+#define utringbuffer_init(a, _n, _icd) do {                               \
+  memset(a, 0, sizeof(UT_ringbuffer));                                    \
+  (a)->icd = *(_icd);                                                     \
+  (a)->n = (_n);                                                          \
+  if ((a)->n) { (a)->d = (char*)malloc((a)->n * (_icd)->sz); }            \
+} while(0)
+
+#define utringbuffer_clear(a) do {                                        \
+  if ((a)->icd.dtor) {                                                    \
+    if ((a)->f) {                                                         \
+      unsigned _ut_i;                                                     \
+      for (_ut_i = 0; _ut_i < (a)->n; ++_ut_i) {                          \
+        (a)->icd.dtor(utringbuffer_eltptr(a, _ut_i));                     \
+      }                                                                   \
+    } else {                                                              \
+      unsigned _ut_i;                                                     \
+      for (_ut_i = 0; _ut_i < (a)->i; ++_ut_i) {                          \
+        (a)->icd.dtor(utringbuffer_eltptr(a, _ut_i));                     \
+      }                                                                   \
+    }                                                                     \
+  }                                                                       \
+  (a)->i = 0;                                                             \
+  (a)->f = 0;                                                             \
+} while(0)
+
+#define utringbuffer_done(a) do {                                         \
+  utringbuffer_clear(a);                                                  \
+  free((a)->d); (a)->d = NULL;                                            \
+  (a)->n = 0;                                                             \
+} while(0)
+
+#define utringbuffer_new(a,n,_icd) do {                                   \
+  a = (UT_ringbuffer*)malloc(sizeof(UT_ringbuffer));                      \
+  utringbuffer_init(a, n, _icd);                                          \
+} while(0)
+
+#define utringbuffer_free(a) do {                                         \
+  utringbuffer_done(a);                                                   \
+  free(a);                                                                \
+} while(0)
+
+#define utringbuffer_push_back(a,p) do {                                                \
+  if ((a)->icd.dtor && (a)->f) { (a)->icd.dtor(_utringbuffer_internalptr(a,(a)->i)); }  \
+  if ((a)->icd.copy) { (a)->icd.copy( _utringbuffer_internalptr(a,(a)->i), p); }        \
+  else { memcpy(_utringbuffer_internalptr(a,(a)->i), p, (a)->icd.sz); };                \
+  if (++(a)->i == (a)->n) { (a)->i = 0; (a)->f = 1; }                                   \
+} while(0)
+
+#define utringbuffer_len(a) ((a)->f ? (a)->n : (a)->i)
+#define utringbuffer_empty(a) ((a)->i == 0 && !(a)->f)
+#define utringbuffer_full(a) ((a)->f != 0)
+
+#define _utringbuffer_real_idx(a,j) ((a)->f ? ((j) + (a)->i) % (a)->n : (j))
+#define _utringbuffer_internalptr(a,j) ((void*)((a)->d + ((a)->icd.sz * (j))))
+#define utringbuffer_eltptr(a,j) ((0 <= (j) && (j) < utringbuffer_len(a)) ? _utringbuffer_internalptr(a,_utringbuffer_real_idx(a,j)) : NULL)
+
+#define _utringbuffer_fake_idx(a,j) ((a)->f ? ((j) + (a)->n - (a)->i) % (a)->n : (j))
+#define _utringbuffer_internalidx(a,e) (((char*)(e) >= (a)->d) ? (((char*)(e) - (a)->d)/(a)->icd.sz) : -1)
+#define utringbuffer_eltidx(a,e) _utringbuffer_fake_idx(a, _utringbuffer_internalidx(a,e))
+
+#define utringbuffer_front(a) utringbuffer_eltptr(a,0)
+#define utringbuffer_next(a,e) ((e)==NULL ? utringbuffer_front(a) : utringbuffer_eltptr(a, utringbuffer_eltidx(a,e)+1))
+#define utringbuffer_prev(a,e) ((e)==NULL ? utringbuffer_back(a) : utringbuffer_eltptr(a, utringbuffer_eltidx(a,e)-1))
+#define utringbuffer_back(a) (utringbuffer_empty(a) ? NULL : utringbuffer_eltptr(a, utringbuffer_len(a) - 1))
+
+#endif /* UTRINGBUFFER_H */

src/photon/photon_scheduler.c

@@ -57,7 +57,8 @@ local_scheduler_state *init_local_scheduler(event_loop *loop,
   state->loop = loop;
   /* Connect to Plasma. This method will retry if Plasma hasn't started yet.
    * Pass in a NULL manager address and port. */
-  state->plasma_conn = plasma_connect(plasma_socket_name, NULL);
+  state->plasma_conn =
+      plasma_connect(plasma_socket_name, NULL, PLASMA_DEFAULT_RELEASE_DELAY);
   /* Subscribe to notifications about sealed objects. */
   int plasma_fd = plasma_subscribe(state->plasma_conn);
   /* Add the callback that processes the notification to the event loop. */
@@ -79,7 +80,7 @@ local_scheduler_state *init_local_scheduler(event_loop *loop,
 
 void free_local_scheduler(local_scheduler_state *s) {
   db_disconnect(s->scheduler_info->db);
-  free(s->plasma_conn);
+  plasma_disconnect(s->plasma_conn);
   worker_index *current_worker_index, *temp_worker_index;
   HASH_ITER(hh, s->worker_index, current_worker_index, temp_worker_index) {
     HASH_DEL(s->worker_index, current_worker_index);

src/plasma/example.c

@@ -25,7 +25,7 @@ int main(int argc, char *argv[]) {
   while ((c = getopt(argc, argv, "s:cfg")) != -1) {
     switch (c) {
     case 's':
-      conn = plasma_connect(optarg, NULL);
+      conn = plasma_connect(optarg, NULL, PLASMA_DEFAULT_RELEASE_DELAY);
       break;
     case 'c':
       assert(conn != NULL);

src/plasma/lib/python/plasma.py

@@ -72,7 +72,7 @@ class PlasmaClient(object):
   strings.
   """
 
-  def __init__(self, store_socket_name, manager_socket_name=None):
+  def __init__(self, store_socket_name, manager_socket_name=None, release_delay=64):
     """Initialize the PlasmaClient.
 
     Args:
@@ -103,10 +103,10 @@ def __init__(self, store_socket_name, manager_socket_name=None):
 
     if manager_socket_name is not None:
       self.has_manager_conn = True
-      self.plasma_conn = ctypes.c_void_p(self.client.plasma_connect(store_socket_name, manager_socket_name))
+      self.plasma_conn = ctypes.c_void_p(self.client.plasma_connect(store_socket_name, manager_socket_name, release_delay))
     else:
       self.has_manager_conn = False
-      self.plasma_conn = ctypes.c_void_p(self.client.plasma_connect(store_socket_name, None))
+      self.plasma_conn = ctypes.c_void_p(self.client.plasma_connect(store_socket_name, None, release_delay))
 
   def shutdown(self):
     """Shutdown the client so that it does not send messages.

src/plasma/plasma_client.c

@@ -19,6 +19,7 @@
 #include "plasma_client.h"
 #include "fling.h"
 #include "uthash.h"
+#include "utringbuffer.h"
 
 /* Number of times we try connecting to a socket. */
 #define NUM_CONNECT_ATTEMPTS 50
@@ -53,6 +54,14 @@ typedef struct {
   UT_hash_handle hh;
 } object_in_use_entry;
 
+/** Configuration options for the plasma client. */
+typedef struct {
+  /** Number of release calls we wait until the object is actually released.
+   *  This allows us to avoid invalidating the cpu cache on workers if objects
+   *  are reused accross tasks. */
+  int release_delay;
+} plasma_client_config;
+
 /** Information about a connection between a Plasma Client and Plasma Store.
  *  This is used to avoid mapping the same files into memory multiple times. */
 struct plasma_connection {
@@ -67,6 +76,13 @@ struct plasma_connection {
   /** A hash table of the object IDs that are currently being used by this
    * client. */
   object_in_use_entry *objects_in_use;
+  /** Object IDs of the last few release calls. This is used to delay
+   *  releasing objects to see if they can be reused by subsequent tasks so we
+   *  do not unneccessarily invalidate cpu caches. TODO(pcm): replace this with
+   *  a proper lru cache of size sizeof(L3 cache). */
+  UT_ringbuffer *release_history;
+  /** Configuration options for the plasma client. */
+  plasma_client_config config;
 };
 
 int plasma_request_size(int num_object_ids) {
@@ -224,7 +240,7 @@ void plasma_get(plasma_connection *conn,
   increment_object_count(conn, object_id, object->handle.store_fd);
 }
 
-void plasma_release(plasma_connection *conn, object_id object_id) {
+void plasma_perform_release(plasma_connection *conn, object_id object_id) {
   /* Decrement the count of the number of instances of this object that are
    * being used by this client. The corresponding increment should have happened
    * in plasma_get. */
@@ -260,6 +276,24 @@ void plasma_release(plasma_connection *conn, object_id object_id) {
   }
 }
 
+void plasma_release(plasma_connection *conn, object_id obj_id) {
+  /* If no ringbuffer is used, don't delay the release. */
+  if (conn->config.release_delay == 0) {
+    plasma_perform_release(conn, obj_id);
+  } else if (!utringbuffer_full(conn->release_history)) {
+    /* Delay the release by storing new releases into a ringbuffer and only
+     * popping them off and actually releasing if the buffer is full. This is
+     * so consecutive tasks don't release and map again objects and invalidate
+     * the cpu cache this way. */
+    utringbuffer_push_back(conn->release_history, &obj_id);
+  } else {
+    object_id object_id_to_release =
+        *(object_id *) utringbuffer_front(conn->release_history);
+    utringbuffer_push_back(conn->release_history, &obj_id);
+    plasma_perform_release(conn, object_id_to_release);
+  }
+}
+
 /* This method is used to query whether the plasma store contains an object. */
 void plasma_contains(plasma_connection *conn,
                      object_id object_id,
@@ -342,7 +376,8 @@ int socket_connect_retry(const char *socket_name,
 }
 
 plasma_connection *plasma_connect(const char *store_socket_name,
-                                  const char *manager_socket_name) {
+                                  const char *manager_socket_name,
+                                  int release_delay) {
   /* Initialize the store connection struct */
   plasma_connection *result = malloc(sizeof(plasma_connection));
   result->store_conn = socket_connect_retry(
@@ -355,6 +390,8 @@ plasma_connection *plasma_connect(const char *store_socket_name,
   }
   result->mmap_table = NULL;
   result->objects_in_use = NULL;
+  result->config.release_delay = release_delay;
+  utringbuffer_new(result->release_history, release_delay, &object_id_icd);
   return result;
 }
 
@@ -363,6 +400,11 @@ void plasma_disconnect(plasma_connection *conn) {
   if (conn->manager_conn >= 0) {
     close(conn->manager_conn);
   }
+  object_id *id = NULL;
+  while ((id = (object_id *) utringbuffer_next(conn->release_history, id))) {
+    plasma_perform_release(conn, *id);
+  }
+  utringbuffer_free(conn->release_history);
   free(conn);
 }
 

src/plasma/plasma_client.h

@@ -3,6 +3,8 @@
 
 #include "plasma.h"
 
+#define PLASMA_DEFAULT_RELEASE_DELAY 64
+
 typedef struct plasma_connection plasma_connection;
 
 /**
@@ -60,7 +62,8 @@ int socket_connect_retry(const char *socket_name,
  * @return The object containing the connection state.
  */
 plasma_connection *plasma_connect(const char *store_socket_name,
-                                  const char *manager_socket_name);
+                                  const char *manager_socket_name,
+                                  int release_delay);
 
 /**
  * Disconnect from the local plasma instance, including the local store and

src/plasma/plasma_manager.c

@@ -249,7 +249,8 @@ plasma_manager_state *init_plasma_manager_state(const char *store_socket_name,
                                                 int db_port) {
   plasma_manager_state *state = malloc(sizeof(plasma_manager_state));
   state->loop = event_loop_create();
-  state->plasma_conn = plasma_connect(store_socket_name, NULL);
+  state->plasma_conn =
+      plasma_connect(store_socket_name, NULL, PLASMA_DEFAULT_RELEASE_DELAY);
   state->manager_connections = NULL;
   state->fetch_connections = NULL;
   if (db_addr) {
@@ -298,7 +299,7 @@ void destroy_plasma_manager_state(plasma_manager_state *state) {
     }
   }
 
-  free(state->plasma_conn);
+  plasma_disconnect(state->plasma_conn);
   event_loop_destroy(state->loop);
   free(state);
 }

src/plasma/plasma_store.c

@@ -68,10 +68,6 @@ struct client {
  * object_table_entry type. */
 UT_icd client_icd = {sizeof(client *), NULL, NULL, NULL};
 
-/* This is used to define the array of object IDs used to define the
- * notification_queue type. */
-UT_icd object_table_entry_icd = {sizeof(object_id), NULL, NULL, NULL};
-
 typedef struct {
   /** Client file descriptor. This is used as a key for the hash table. */
   int subscriber_fd;
@@ -420,7 +416,7 @@ void subscribe_to_updates(client *client_context, int conn) {
   notification_queue *queue =
       (notification_queue *) malloc(sizeof(notification_queue));
   queue->subscriber_fd = fd;
-  utarray_new(queue->object_ids, &object_table_entry_icd);
+  utarray_new(queue->object_ids, &object_id_icd);
   HASH_ADD_INT(plasma_state->pending_notifications, subscriber_fd, queue);
 }
 

src/plasma/test/manager_tests.c

@@ -101,16 +101,17 @@ plasma_mock *init_plasma_mock(plasma_mock *remote_mock) {
     mock->write_conn =
         get_manager_connection(remote_mock->state, manager_addr, mock->port);
     wait_for_pollin(mock->manager_remote_fd);
-    mock->read_conn = new_client_connection(mock->loop, mock->manager_remote_fd,
-                                            mock->state, 0);
+    mock->read_conn =
+        new_client_connection(mock->loop, mock->manager_remote_fd, mock->state,
+                              PLASMA_DEFAULT_RELEASE_DELAY);
   } else {
     mock->write_conn = NULL;
     mock->read_conn = NULL;
   }
   /* Connect a new client to the local plasma manager and mock a request to an
    * object. */
   mock->plasma_conn = plasma_connect(utstring_body(store_socket_name),
-                                     utstring_body(manager_socket_name));
+                                     utstring_body(manager_socket_name), 0);
   wait_for_pollin(mock->manager_local_fd);
   mock->client_conn =
       new_client_connection(mock->loop, mock->manager_local_fd, mock->state, 0);
@@ -126,7 +127,7 @@ void destroy_plasma_mock(plasma_mock *mock) {
   }
   destroy_plasma_manager_state(mock->state);
   free(mock->client_conn);
-  free(mock->plasma_conn);
+  plasma_disconnect(mock->plasma_conn);
   close(mock->local_store);
   close(mock->manager_local_fd);
   close(mock->manager_remote_fd);