## 4 Results and Analysis
### System Testing for the Multi-Tasking Video Streaming Delivery  
The status-byte-assisted RDMA transmission mechanism supports multi-task processing because each memory block has an independent status byte indicating its usage status. In contrast, the sliding window RDMA transmission mechanism utilizes only two pointers, which require memory blocks to be used and released sequentially. This can lead to contention for pointer resources when multiple threads send data, and the order of returned ACKs can be inconsistent due to various factors when multiple threads receive data. Therefore, the sliding window RDMA transmission mechanism does not effectively support parallel multi-threading. For transmitting real-time video streams from multiple cameras, typically, multiple sliding window programs are needed for the sliding window RDMA transmission mechanism, whereas only one status-byte-assisted RDMA transmission program is necessary for the status-byte-assisted RDMA transmission mechanism.  
In this experiment, 12 simulated cameras were used, each filling memory blocks with 25 frames of data per second; the size of each frame is 640 \(\times\) 480 \(\times\) 3 bytes, and the system's throughput variation over time is recorded. Figure 19 shows the throughput variations in multitasking scenarios using both the sliding window RDMA transmission mechanism and the status-byte-assisted RDMA transmission mechanism. As shown in Figure 19, the overall throughput of the status-byte-assisted RDMA transmission mechanism remains relatively stable, concentrating around 7000 MB/s over a longer period. This is because the status-byte-assisted RDMA transmission mechanism sequentially queries the first status-byte memory block and sends memory blocks serially. The periods where throughput is zero indicate that no data need to be sent, during which the program enters a sleep mode and periodically checks for new data to send. In contrast, the throughput of the sliding window RDMA transmission mechanism fluctuates significantly over time, with a broader range of transmission rates compared to the status-byte-assisted mechanism. This is because each sliding window RDMA transmission program's transmission times are independent, and multiple memory blocks can sometimes be transmitted in parallel, causing substantial throughput variations and leading to unstable performance. Moreover, when transmitting multiple data streams over the same period, the status-byte-assisted RDMA transmission mechanism demonstrates more stable throughput than the sliding window RDMA transmission mechanism, thus enhancing the system's stability and reliability while avoiding resource waste and bottlenecks.  
During the transmission process, the average CPU utilization of the status-byte-assisted RDMA transmission mechanism is 106% and memory usage is 1.3%. In contrast, the sliding window RDMA transmission mechanism has an overall average CPU utilization of 168% and memory usage of 2.4%. In summary, the status-byte-assisted RDMA transmission mechanism maintains a smooth throughput curve by efficiently organizing tasks on the sending end and concentrating them into a single QP, while also saving CPU and memory resources and reducing RNIC resource consumption.  
To summarize the key findings and facilitate a clear comparison between the two RDMA transmission mechanisms, the following Table 3 is provided. This table highlights  
Figure 19: Throughput variation in multitasking: (**a**) the sliding window RDMA transmission mechanism and (**b**) the status-byte-assisted RDMA transmission mechanism.  
the main strengths and weaknesses of each approach, offering a concise overview of the performance, resource utilization, and specific features discussed above.