diff --git a/src/event/ngx_event.c b/src/event/ngx_event.c
index b50b873..7bfda04 100644
--- a/src/event/ngx_event.c
+++ b/src/event/ngx_event.c
@@ -139,6 +139,7 @@
 
 static ngx_int_t ngx_event_module_init(ngx_cycle_t *cycle)
 {
+#if !(WIN32)
     ngx_core_conf_t   *ccf;
     ngx_event_conf_t  *ecf;
 
@@ -163,6 +164,7 @@
                       "mmap(MAP_ANON|MAP_SHARED) failed");
         return NGX_ERROR;
     }
+#endif
 
     return NGX_OK;
 }
diff --git a/src/event/ngx_event_pipe.c b/src/event/ngx_event_pipe.c
index f254517..d7136bf 100644
--- a/src/event/ngx_event_pipe.c
+++ b/src/event/ngx_event_pipe.c
@@ -100,7 +100,6 @@
 
             /* use the pre-read hunks if they exist */
 
-            p->read = 1;
             chain = p->preread_hunks;
             p->preread_hunks = NULL;
             n = p->preread_size;
@@ -108,6 +107,10 @@
             ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
                            "pipe preread: %d", n);
 
+            if (n) {
+                p->read = 1;
+            }
+
         } else {
 
             /*
@@ -286,6 +289,35 @@
         p->free_raw_hunks = cl;
     }
 
+#if (NGX_DEBUG0)
+
+    if (p->in || p->busy || p->free_raw_hunks) {
+        ngx_log_debug0(NGX_LOG_DEBUG_EVENT, p->log, 0, "pipe buf");
+    }
+
+    for (cl = p->in; cl; cl = cl->next) {
+        ngx_log_debug3(NGX_LOG_DEBUG_EVENT, p->log, 0,
+                       "pipe buf in " PTR_FMT ", pos " PTR_FMT ", size: %d",
+                       cl->hunk->start, cl->hunk->pos,
+                       cl->hunk->last - cl->hunk->pos);
+    }
+
+    for (cl = p->busy; cl; cl = cl->next) {
+        ngx_log_debug3(NGX_LOG_DEBUG_EVENT, p->log, 0,
+                       "pipe buf busy " PTR_FMT ", pos " PTR_FMT ", size: %d",
+                       cl->hunk->start, cl->hunk->pos,
+                       cl->hunk->last - cl->hunk->pos);
+    }
+
+    for (cl = p->free_raw_hunks; cl; cl = cl->next) {
+        ngx_log_debug3(NGX_LOG_DEBUG_EVENT, p->log, 0,
+                       "pipe buf free " PTR_FMT ", last " PTR_FMT ", size: %d",
+                       cl->hunk->start, cl->hunk->last,
+                       cl->hunk->end - cl->hunk->last);
+    }
+
+#endif
+
     if ((p->upstream_eof || p->upstream_error) && p->free_raw_hunks) {
 
         /* STUB */ p->free_raw_hunks->hunk->num = p->num++;
@@ -315,7 +347,8 @@
 
 int ngx_event_pipe_write_to_downstream(ngx_event_pipe_t *p)
 {
-    size_t        bsize, to_write;
+    size_t        bsize;
+    ngx_uint_t    flush;
     ngx_hunk_t   *h;
     ngx_chain_t  *out, **ll, *cl, *tl;
 
@@ -368,44 +401,29 @@
             break;
         }
 
-        /*
-         * bsize is the size of the busy hunks,
-         * to_write is the size of data in these hunks that
-         * would be written to a socket
-         */
+        /* bsize is the size of the busy hunks */
 
         bsize = 0;
-        to_write = 0;
 
-#if 0
-        if (!(p->upstream_eof || p->upstream_error || p->upstream_done)) {
-#endif
-            for (cl = p->busy; cl; cl = cl->next) {
-                bsize += cl->hunk->end - cl->hunk->start;
-                to_write += ngx_hunk_size(cl->hunk);
-            }
-#if 0
+        for (cl = p->busy; cl; cl = cl->next) {
+            bsize += cl->hunk->end - cl->hunk->start;
         }
-#endif
+
+        ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
+                       "pipe write busy: " SIZE_T_FMT, bsize);
 
         out = NULL;
         ll = NULL;
+        flush = 0;
 
         for ( ;; ) {
             if (p->out) {
                 cl = p->out;
 
-#if 0
-                if (!(p->upstream_eof || p->upstream_error || p->upstream_done)
-                    && (bsize + ngx_hunk_size(cl->hunk) > p->busy_size))
-                {
-                    break;
-                }
-#else
                 if (bsize + ngx_hunk_size(cl->hunk) > p->busy_size) {
+                    flush = 1;
                     break;
                 }
-#endif
 
                 p->out = p->out->next;
                 ngx_event_pipe_free_shadow_raw_hunk(&p->free_raw_hunks,
@@ -414,17 +432,10 @@
             } else if (!p->cachable && p->in) {
                 cl = p->in;
 
-#if 0
-                if (!(p->upstream_eof || p->upstream_error || p->upstream_done)
-                    && (bsize + ngx_hunk_size(cl->hunk) > p->busy_size))
-                {
-                    break;
-                }
-#else
                 if (bsize + ngx_hunk_size(cl->hunk) > p->busy_size) {
+                    flush = 1;
                     break;
                 }
-#endif
 
                 p->in = p->in->next;
 
@@ -437,22 +448,13 @@
             ngx_chain_add_link(out, ll, cl);
         }
 
-        if (out == NULL) {
+        ngx_log_debug2(NGX_LOG_DEBUG_EVENT, p->log, 0,
+                       "pipe write: out:" PTR_FMT ", f:%d", out, flush);
 
-            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
-                           "pipe busy hunk data to write: %d", to_write);
-
-            if (!(p->upstream_blocked && to_write)) {
-                break;
-            }
-
+        if (out == NULL && !flush) {
+            break;
         }
 
-        /*
-         * if the upstream is blocked and there are the busy hunks
-         * to write then write these hunks
-         */
-
         if (p->output_filter(p->output_ctx, out) == NGX_ERROR) {
             p->downstream_error = 1;
             return ngx_event_pipe_drain_chains(p);
@@ -533,8 +535,9 @@
         do {
             hsize = cl->hunk->last - cl->hunk->pos;
 
-            ngx_log_debug1(NGX_LOG_DEBUG_EVENT, p->log, 0,
-                           "pipe hunk size: %d", hsize);
+            ngx_log_debug3(NGX_LOG_DEBUG_EVENT, p->log, 0,
+                           "pipe buf " PTR_FMT ", pos " PTR_FMT ", size: %d",
+                           cl->hunk->start, cl->hunk->pos, hsize);
 
             if ((size + hsize > p->temp_file_write_size)
                || (p->temp_file->offset + size + hsize > p->max_temp_file_size))
diff --git a/src/event/ngx_event_timer.h b/src/event/ngx_event_timer.h
index 0eae570..bf5d155 100644
--- a/src/event/ngx_event_timer.h
+++ b/src/event/ngx_event_timer.h
@@ -77,7 +77,14 @@
 #endif
 
     if (ev->timer_set) {
-        if (key - ev->rbtree_key < 50) {
+
+        /*
+         * Use the previous timer value if a difference between them is less
+         * then 100 milliseconds.  It allows to minimize the rbtree operations
+         * for the fast connections.
+         */
+
+        if (key - ev->rbtree_key < 100 / NGX_TIMER_RESOLUTION) {
             ngx_log_debug3(NGX_LOG_DEBUG_EVENT, ev->log, 0,
                            "event timer: %d, old: %d, new: %d",
                             ngx_event_ident(ev->data), ev->rbtree_key, key);
diff --git a/src/http/modules/proxy/ngx_http_proxy_handler.c b/src/http/modules/proxy/ngx_http_proxy_handler.c
index 0dba23f..95d5654 100644
--- a/src/http/modules/proxy/ngx_http_proxy_handler.c
+++ b/src/http/modules/proxy/ngx_http_proxy_handler.c
@@ -814,6 +814,8 @@
     ngx_http_proxy_loc_conf_t *prev = parent;
     ngx_http_proxy_loc_conf_t *conf = child;
 
+    size_t   size;
+
     ngx_conf_merge_msec_value(conf->connect_timeout,
                               prev->connect_timeout, 60000);
     ngx_conf_merge_msec_value(conf->send_timeout, prev->send_timeout, 30000);
@@ -823,22 +825,65 @@
     ngx_conf_merge_value(conf->add_x_forwarded_for,
                          prev->add_x_forwarded_for, 0);
 
+    ngx_conf_merge_msec_value(conf->read_timeout, prev->read_timeout, 30000);
+
     ngx_conf_merge_size_value(conf->header_buffer_size,
                               prev->header_buffer_size, 4096);
-    ngx_conf_merge_msec_value(conf->read_timeout, prev->read_timeout, 30000);
     ngx_conf_merge_bufs_value(conf->bufs, prev->bufs, 8, 4096);
-    ngx_conf_merge_size_value(conf->busy_buffers_size,
-                              prev->busy_buffers_size, 8192);
 
-#if 0
-    if (conf->max_temp_file_size > conf->bufs.size) {
-        return "\"proxy_max_temp_file\" must be greater "
-               "than one of the \"proxy_buffers\"";
+    size = conf->header_buffer_size;
+    if (size < conf->bufs.size) {
+        size = conf->bufs.size;
     }
-#endif
+
+
+    ngx_conf_merge_size_value(conf->busy_buffers_size,
+                              prev->busy_buffers_size, NGX_CONF_UNSET_SIZE);
+
+    if (conf->busy_buffers_size == NGX_CONF_UNSET_SIZE) {
+        conf->busy_buffers_size = 2 * size;
+
+    } else if (conf->busy_buffers_size < size) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+             "\"proxy_busy_buffers_size\" must be equal or bigger than "
+             "maximum of the value of \"proxy_header_buffer_size\" and "
+             "one of the \"proxy_buffers\"");
+
+        return NGX_CONF_ERROR;
+    }
+
 
     ngx_conf_merge_size_value(conf->temp_file_write_size,
-                              prev->temp_file_write_size, 16384);
+                              prev->temp_file_write_size, NGX_CONF_UNSET_SIZE);
+
+    if (conf->temp_file_write_size == NGX_CONF_UNSET_SIZE) {
+        conf->temp_file_write_size = 2 * size;
+
+    } else if (conf->temp_file_write_size < size) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+             "\"proxy_temp_file_write_size\" must be equal or bigger than "
+             "maximum of the value of \"proxy_header_buffer_size\" and "
+             "one of the \"proxy_buffers\"");
+
+        return NGX_CONF_ERROR;
+    }
+
+
+    ngx_conf_merge_size_value(conf->max_temp_file_size,
+                              prev->max_temp_file_size, NGX_CONF_UNSET_SIZE);
+
+    if (conf->max_temp_file_size == NGX_CONF_UNSET_SIZE) {
+        conf->max_temp_file_size = 2 * size;
+
+    } else if (conf->max_temp_file_size < size) {
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
+             "\"proxy_max_temp_file_size\" must be equal or bigger than "
+             "maximum of the value of \"proxy_header_buffer_size\" and "
+             "one of the \"proxy_buffers\"");
+
+        return NGX_CONF_ERROR;
+    }
+
 
     ngx_conf_merge_bitmask_value(conf->next_upstream, prev->next_upstream,
                                  (NGX_CONF_BITMASK_SET
diff --git a/src/http/modules/proxy/ngx_http_proxy_upstream.c b/src/http/modules/proxy/ngx_http_proxy_upstream.c
index bd4befd..d279759 100644
--- a/src/http/modules/proxy/ngx_http_proxy_upstream.c
+++ b/src/http/modules/proxy/ngx_http_proxy_upstream.c
@@ -1199,14 +1199,16 @@
 
     ep->preread_size = p->header_in->last - p->header_in->pos;
 
-    ep->hunk_to_file = ngx_calloc_hunk(r->pool);
-    if (ep->preread_hunks == NULL) {
-        ngx_http_proxy_finalize_request(p, 0);
-        return;
+    if (p->cachable) {
+        ep->hunk_to_file = ngx_calloc_hunk(r->pool);
+        if (ep->hunk_to_file == NULL) {
+            ngx_http_proxy_finalize_request(p, 0);
+            return;
+        }
+        ep->hunk_to_file->pos = p->header_in->start;
+        ep->hunk_to_file->last = p->header_in->pos;
+        ep->hunk_to_file->type = NGX_HUNK_IN_MEMORY|NGX_HUNK_TEMP;
     }
-    ep->hunk_to_file->pos = p->header_in->start;
-    ep->hunk_to_file->last = p->header_in->pos;
-    ep->hunk_to_file->type = NGX_HUNK_IN_MEMORY|NGX_HUNK_TEMP;
 
     if (ngx_event_flags & NGX_USE_AIO_EVENT) {
         /* the posted aio operation can currupt a shadow buffer */