fix #249, cache the chunk headers info to +5% or +10% performance. 2.0.51

@@ -31,7 +31,7 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 // current release version
 #define VERSION_MAJOR       2
 #define VERSION_MINOR       0
-#define VERSION_REVISION    50
+#define VERSION_REVISION    51
 // server info.
 #define RTMP_SIG_SRS_KEY "SRS"
 #define RTMP_SIG_SRS_ROLE "origin/edge server"

@@ -79,5 +79,12 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */
 #define SRS_PERF_SEND_MSGS_CACHE 500
 
+/**
+* how many chunk stream to cache, [0, N].
+* to imporove about 10% performance when chunk size small, and 5% for large chunk.
+* @see https://github.com/winlinvip/simple-rtmp-server/issues/249
+*/
+#define SRS_PERF_CHUNK_STREAM_CACHE 16
+
 #endif
 

@@ -417,6 +417,16 @@ SrsProtocol::SrsProtocol(ISrsProtocolReaderWriter* io)
     
     warned_c0c3_cache_dry = false;
     auto_response_when_recv = true;
+    
+    cs_cache = new SrsChunkStream*[SRS_PERF_CHUNK_STREAM_CACHE];
+    for (int cid = 0; cid < SRS_PERF_CHUNK_STREAM_CACHE; cid++) {
+        SrsChunkStream* cs = new SrsChunkStream(cid);
+        // set the perfer cid of chunk,
+        // which will copy to the message received.
+        cs->header.perfer_cid = cid;
+        
+        cs_cache[cid] = cs;
+    }
 }
 
 SrsProtocol::~SrsProtocol()
@@ -448,6 +458,13 @@ SrsProtocol::~SrsProtocol()
         free(out_iovs);
         out_iovs = NULL;
     }
+    
+    // free all chunk stream cache.
+    for (int i = 0; i < SRS_PERF_CHUNK_STREAM_CACHE; i++) {
+        SrsChunkStream* cs = cs_cache[i];
+        srs_freep(cs);
+    }
+    srs_freep(cs_cache);
 }
 
 void SrsProtocol::set_auto_response(bool v)
@@ -1102,17 +1119,30 @@ int SrsProtocol::recv_interlaced_message(SrsMessage** pmsg)
     // get the cached chunk stream.
     SrsChunkStream* chunk = NULL;
     
-    if (chunk_streams.find(cid) == chunk_streams.end()) {
-        chunk = chunk_streams[cid] = new SrsChunkStream(cid);
-        // set the perfer cid of chunk,
-        // which will copy to the message received.
-        chunk->header.perfer_cid = cid;
-        srs_verbose("cache new chunk stream: fmt=%d, cid=%d", fmt, cid);
-    } else {
-        chunk = chunk_streams[cid];
+    // use chunk stream cache to get the chunk info.
+    // @see https://github.com/winlinvip/simple-rtmp-server/issues/249
+    if (cid < SRS_PERF_CHUNK_STREAM_CACHE) {
+        // chunk stream cache hit.
+        srs_verbose("cs-cache hit, cid=%d", cid);
+        // already init, use it direclty
+        chunk = cs_cache[cid];
         srs_verbose("cached chunk stream: fmt=%d, cid=%d, size=%d, message(type=%d, size=%d, time=%"PRId64", sid=%d)",
             chunk->fmt, chunk->cid, (chunk->msg? chunk->msg->size : 0), chunk->header.message_type, chunk->header.payload_length,
             chunk->header.timestamp, chunk->header.stream_id);
+    } else {
+        // chunk stream cache miss, use map.
+        if (chunk_streams.find(cid) == chunk_streams.end()) {
+            chunk = chunk_streams[cid] = new SrsChunkStream(cid);
+            // set the perfer cid of chunk,
+            // which will copy to the message received.
+            chunk->header.perfer_cid = cid;
+            srs_verbose("cache new chunk stream: fmt=%d, cid=%d", fmt, cid);
+        } else {
+            chunk = chunk_streams[cid];
+            srs_verbose("cached chunk stream: fmt=%d, cid=%d, size=%d, message(type=%d, size=%d, time=%"PRId64", sid=%d)",
+                chunk->fmt, chunk->cid, (chunk->msg? chunk->msg->size : 0), chunk->header.message_type, chunk->header.payload_length,
+                chunk->header.timestamp, chunk->header.stream_id);
+        }
     }
 
     // chunk stream message header

@@ -205,6 +205,12 @@ private:
     */
     std::map<int, SrsChunkStream*> chunk_streams;
     /**
+    * cache some frequently used chunk header.
+    * cs_cache, the chunk stream cache.
+    * @see https://github.com/winlinvip/simple-rtmp-server/issues/249
+    */
+    SrsChunkStream** cs_cache;
+    /**
     * bytes buffer cache, recv from skt, provide services for stream.
     */
     SrsFastBuffer* in_buffer;