Re: [Tinycc-devel] Huge swings in cache performance

[Edmund Grimley Evans]

Are you dynamically generating code on Intel? But presumably the
dynamically generated code is not inside your loop? However, if your
dynamically generated code is adjacent in memory to some data that
gets modified, then it could be (I have no idea how this stuff works
on Intel) that the processor thinks that the code may have been
modified, even though it hasn't been modified, and invalidates the
cache just in case. And this phenomenon would be very sensitive to the
precise layout. The solution might be to put the dynamically generated
code in a block of memory that is separately allocated with mmap. On
the other hand, if you're already doing that, probably this isn't the
explanation.

Edmund