Friday, January 5, 2018

Performance workaround for Meltdown and Spectre exploits/vulerabilities

Those of us familiar with kernel-bypass techniques are keenly aware of the overhead in the user/kernel transition, especially when multiplexing many thousands of tcp sockets.

Believe it or not, Windows already has the pieces needed to recover the lost performance, due to the new security fix overhead found in the user/kernel transition when doing socket i/o. We can create what is essentially a user-mode tcpip stack using Windows RIO (aka Registered i/o) to batch many tcpip packets into a single user/kernel transition. Combine with the User Mode Scheduler (UMS), which basically intercepts i/o calls, before incurring the overhead of the user/kernel transition, and batches these calls into our RIO based tcpip engine.

This infrastructure could then be a shim layer within windows docker containers running both windows and linux.

What we need now is a UMS concept on the linux side so the same can be done.

BTW, Intel CEO Brian Krzanich needs to go asap. Given the stock sale, he is doing more harm than good.