diff --git a/README.md b/README.md
index c2a8c346f..8edd05b8c 100755
--- a/README.md
+++ b/README.md
@@ -1066,6 +1066,7 @@ The performance benchmark data and corelative commits are listed here.
 * See also: [Performance for x86/x64 Test Guide][v1_CN_Performance].
 * See also: [Performance for RaspberryPi][v1_CN_RaspberryPi].
 * For multiple processes performance, read [#775: REUSEPORT][bug #775] or OriginCluster([CN][v3_EN_OriginCluster]/[EN][v3_EN_OriginCluster]) or [go-oryx][oryx].
+* For RTC benchmark, please use [srs-bench](https://github.com/ossrs/srs-bench/tree/feature/rtc#usage).
 
 <a name="play-rtmp-benchmark"></a>
 **Play RTMP benchmark**
@@ -1119,6 +1120,19 @@ The data for playing HTTP FLV was benchmarked by [SB][srs-bench]:
 |   2014-05-24  |   2.0.168 |   2.3k(2300)  |   players     |   92%     |   276MB   |   [code][p17] |
 |   2014-05-24  |   2.0.167 |   1.0k(1000)  |   players     |   82%     |   86MB    |   -           |
 
+<a name="rtc-benchmark"></a>
+**RTC benchmark**
+
+The RTC benchmark data, by [srs-bench](https://github.com/ossrs/srs-bench/tree/feature/rtc#usage):
+
+
+|   Update      |    SRS    |    Clients    |     Type      |    CPU    |  Memory   | Threads | 
+| ------------- | --------- | ------------- | ------------- | --------- | --------  | ------- |
+|   2021-03-31  |   4.0.87  |   550         |   publishers  |   ~86%     |   1.3GB   | 1      |
+|   2021-03-31  |   4.0.87  |   800         |   players     |   ~94%     |   444MB   | 1      |
+
+> Note: CentOS7, 500Kbps, 4CPU, 2.5 GHz Intel Xeon Platinum 8163/8269CY.
+
 <a name="latency-benchmark"></a>
 **Latency benchmark**
 
diff --git a/trunk/src/kernel/srs_kernel_rtc_rtp.cpp b/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
index 73ba782e0..4b60ca353 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtp.cpp
@@ -1040,6 +1040,7 @@ srs_error_t SrsRtpPacket2::decode(SrsBuffer* buf)
         nalu_type = SrsAvcNaluType((uint8_t)(buf->head()[0] & kNalTypeMask));
     }
 
+    // TODO: FIXME: We should keep payload to NULL and return if buffer is empty.
     // If user set the decode handler, call it to set the payload.
     if (decode_handler) {
         decode_handler->on_before_decode_payload(this, buf, &payload_, &payload_type_);
diff --git a/trunk/src/kernel/srs_kernel_rtc_rtp.hpp b/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
index 7b1fe5d24..09ce5c716 100644
--- a/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
+++ b/trunk/src/kernel/srs_kernel_rtc_rtp.hpp
@@ -294,8 +294,10 @@ private:
 private:
     // The original shared message, all RTP packets can refer to its data.
     // Note that the size of shared msg, is not the packet size, it's a larger aligned buffer.
+    // @remark Note that it may point to the whole RTP packet(for RTP parser, which decode RTP packet from buffer),
+    //      and it may point to the RTP payload(for RTMP to RTP, which build RTP header and payload).
     SrsSharedPtrMessage* shared_buffer_;
-    // The size of original packet.
+    // The size of RTP packet or RTP payload.
     int actual_buffer_size_;
 // Helper fields.
 public:
@@ -333,6 +335,7 @@ public:
     // Parse the TWCC extension, ignore by default.
     void enable_twcc_decode() { header.enable_twcc_decode(); } // SrsRtpPacket2::enable_twcc_decode
     // Get and set the payload of packet.
+    // @remark Note that return NULL if no payload.
     void set_payload(ISrsRtpPayloader* p, SrsRtpPacketPayloadType pt) { payload_ = p; payload_type_ = pt; }
     ISrsRtpPayloader* payload() { return payload_; }
     // Set the padding of RTP packet.