Boosting upload speed and improving Windows' TCP stack
I had a similar issue with Windows kernels &quot;recently&quot; (2016~?)...<p>I don&#x27;t have the memory or patience to write a long and inspiring blog post, but it comes down to:<p>Even with IOCP&#x2F;multiple threads: network traffic is single threaded in the kernel, even worse, there&#x27;s a mutex there. Putting the effective limit on PPS for windows to something like 1.1M for 3.0GHz.<p>The task of this machine was &#x2F;basically&#x2F; a connection multiplexer with some TLS offloading; so listen on a socket, get an encrypted connection, check your connection pool and forward where appropriate.<p>Our machine basically sat waiting (in kernel space) for this lock 99.7% of the time, 0.3% was spent on SSL handshaking..<p>We solved our &quot;issue&quot; by spreading such load over many more machines and gave them low-core-count high-clock-speed Xeons instead of the normal complement of 20vCPU Xeons.<p>AFAIK that issue persists, I&#x27;d be interested to know if someone else managed to coerce windows to do the right thing here.