Not necessarily - it depends on exactly what was changed ... which unfortunately I don't know for certain. Any filesystem call is a kernel transition. That's a Meltdown issue. Meltdown can be avoided by using trampoline functions to call the (real) kernel functions and isolating each trampoline so that no other code immediately follows it. This wastes some memory but there is very little added time cost. Spectre is about snooping within the user space of a single process - it has nothing to do with kernel calls. The issues with Spectre are things like untrusted code breaking out of "sandboxes", snooping on password handling or encryption, etc. Fixing Spectre requires purposefully limiting speculative execution of code and can significantly affect performance. But the effects are situation dependent.
I don't know the details either. But one of proposed fixes was to flush CPU caches after doing system calls. That's the reason why I'm asking.
So now you know that 32GB is better for your workload than 8GB. But that is not necessarily a reason immediately to go crazy with it. Try increasing it gradually - e.g., adding 16GB at a time - and see if the additional shared space provides any real benefit.
That's what we're going to do. Thanks! Regards, Vitaliy
