From 89abfdf52a35cd78e921bc7b6f44c346ddde9bd4 Mon Sep 17 00:00:00 2001
From: Michael Vrable <mvrable@cs.ucsd.edu>
Date: Sat, 12 Mar 2011 20:32:55 -0800
Subject: [PATCH] Try to improve support for no-aggregation mode

Make it at least a bit more performance-competitive by fetching objects
when prefetching is requested.
---
 bluesky/bluesky-private.h |  1 +
 bluesky/cleaner.c         |  4 ++--
 bluesky/cloudlog.c        | 40 +++++++++++++++++++++++++++++++++------
 bluesky/init.c            |  1 +
 4 files changed, 38 insertions(+), 8 deletions(-)

diff --git a/bluesky/bluesky-private.h b/bluesky/bluesky-private.h
index 117f108..5a55b79 100644
--- a/bluesky/bluesky-private.h
+++ b/bluesky/bluesky-private.h
@@ -357,6 +357,7 @@ void bluesky_cloudlog_insert_locked(BlueSkyCloudLog *log);
 BlueSkyCloudLog *bluesky_cloudlog_get(BlueSkyFS *fs, BlueSkyCloudID id);
 void bluesky_cloudlog_prefetch(BlueSkyCloudLog *log);
 void bluesky_cloudlog_fetch(BlueSkyCloudLog *log);
+void bluesky_cloudlog_background_fetch(BlueSkyCloudLog *item);
 BlueSkyCloudPointer bluesky_cloudlog_serialize(BlueSkyCloudLog *log,
                                                BlueSkyFS *fs);
 void bluesky_cloudlog_flush(BlueSkyFS *fs);
diff --git a/bluesky/cleaner.c b/bluesky/cleaner.c
index 0fc39df..5f241d4 100644
--- a/bluesky/cleaner.c
+++ b/bluesky/cleaner.c
@@ -244,8 +244,8 @@ static void merge_inode(BlueSkyFS *fs, BlueSkyCleanerItem *cleaner_inode)
 
     BlueSkyCloudLog *proxy_item = entry->item;
     g_mutex_lock(proxy_item->lock);
-    BlueSkyCloudPointer proxy_location = entry->item->location;
-    BlueSkyCloudID proxy_id = entry->item->id;
+    //BlueSkyCloudPointer proxy_location = entry->item->location;
+    //BlueSkyCloudID proxy_id = entry->item->id;
     g_mutex_unlock(proxy_item->lock);
     g_mutex_unlock(fs->lock);
 
diff --git a/bluesky/cloudlog.c b/bluesky/cloudlog.c
index 3e30f02..628fc97 100644
--- a/bluesky/cloudlog.c
+++ b/bluesky/cloudlog.c
@@ -192,12 +192,6 @@ void bluesky_cloudlog_unref_delayed(BlueSkyCloudLog *log)
         g_async_queue_push(log->fs->unref_queue, log);
 }
 
-void bluesky_cloudlog_threads_init(BlueSkyFS *fs)
-{
-    fs->unref_queue = g_async_queue_new();
-    g_thread_create(cloudlog_unref_thread, fs->unref_queue, FALSE, NULL);
-}
-
 /* Erase the information contained within the in-memory cloud log
  * representation.  This does not free up the item itself, but frees the data
  * and references to other log items and resets the type back to unknown.  If
@@ -271,6 +265,25 @@ BlueSkyCloudLog *bluesky_cloudlog_get(BlueSkyFS *fs, BlueSkyCloudID id)
     return item;
 }
 
+/* Work to fetch a cloudlog item in a background thread.  The item will be
+ * locked while the fetch is in progress and unlocked when it completes. */
+static GThreadPool *fetch_pool;
+
+static void background_fetch_task(gpointer p, gpointer unused)
+{
+    BlueSkyCloudLog *item = (BlueSkyCloudLog *)p;
+
+    g_mutex_lock(item->lock);
+    g_mutex_unlock(item->lock);
+    bluesky_cloudlog_unref(item);
+}
+
+void bluesky_cloudlog_background_fetch(BlueSkyCloudLog *item)
+{
+    bluesky_cloudlog_ref(item);
+    g_thread_pool_push(fetch_pool, item, NULL);
+}
+
 /* Attempt to prefetch a cloud log item.  This does not guarantee that it will
  * be made available, but does make it more likely that a future call to
  * bluesky_cloudlog_fetch will complete quickly.  Item must be locked? */
@@ -279,6 +292,13 @@ void bluesky_cloudlog_prefetch(BlueSkyCloudLog *item)
     if (item->data != NULL)
         return;
 
+    /* When operating in a non log-structured mode, simply start a background
+     * fetch immediately when asked to prefetch. */
+    if (bluesky_options.disable_aggregation) {
+        bluesky_cloudlog_background_fetch(item);
+        return;
+    }
+
     /* TODO: Some of the code here is duplicated with bluesky_log_map_object.
      * Refactor to fix that. */
     BlueSkyFS *fs = item->fs;
@@ -635,3 +655,11 @@ void bluesky_cloudlog_decrypt(char *segment, size_t len,
         remaining_size -= item_size;
     }
 }
+
+void bluesky_cloudlog_threads_init(BlueSkyFS *fs)
+{
+    fs->unref_queue = g_async_queue_new();
+    g_thread_create(cloudlog_unref_thread, fs->unref_queue, FALSE, NULL);
+    fetch_pool = g_thread_pool_new(background_fetch_task, NULL, 40, FALSE,
+                                   NULL);
+}
diff --git a/bluesky/init.c b/bluesky/init.c
index 49ede3e..9ce20b9 100644
--- a/bluesky/init.c
+++ b/bluesky/init.c
@@ -45,6 +45,7 @@ static struct {
     const char *env;
     int *option;
 } option_table[] = {
+    {"BLUESKY_VERBOSE", &bluesky_verbose},
     {"BLUESKY_OPT_SYNC_STORES", &bluesky_options.synchronous_stores},
     {"BLUESKY_OPT_WRITETHROUGH", &bluesky_options.writethrough_cache},
     {"BLUESKY_OPT_SYNC_INODE_FETCH", &bluesky_options.sync_inode_fetches},
-- 
2.20.1