As I said, we live in post-meltdown world. Microkernels are MUCH slower.
I’ve heard this from several people, but you’re the lucky number by which I’d heard it enough that I bothered to gather some references to refute this.
First, this is an argument that derived from first generation microkernels, and in particular, MINIX, which - as a teaching aid OS, never tried to play the benchmark game. It’s been repeated, like dogma, through several iterations of microkernels which have, in the interim, largely erased most of those performance leads of monolithic kernels. One paper notes that, once the working code exceeds the L2 cache size, there is marginal advantage to the monolithic structure. A second paper running benchmarks on L4Linux vs Linux concluded that the microkernel penalty was only about 5%-10% slower for applications than the Linux monolithic kernel.
This is not MUCH slower, and - indeed - unless you’re doing HPC applications, is close enough to be unnoticeable.
Edit: I was originally going to omit this, as it’s propaganda from a vested interest, and includes no concrete numbers, but this blog entry from a product manager at QNX specifically mentions using microkernels in HPC problem spaces, which I thought was interesting, so I’m post-facto including it.
I’ve heard this from several people, but you’re the lucky number by which I’d heard it enough that I bothered to gather some references to refute this.
First, this is an argument that derived from first generation microkernels, and in particular, MINIX, which - as a teaching aid OS, never tried to play the benchmark game. It’s been repeated, like dogma, through several iterations of microkernels which have, in the interim, largely erased most of those performance leads of monolithic kernels. One paper notes that, once the working code exceeds the L2 cache size, there is marginal advantage to the monolithic structure. A second paper running benchmarks on L4Linux vs Linux concluded that the microkernel penalty was only about 5%-10% slower for applications than the Linux monolithic kernel.
This is not MUCH slower, and - indeed - unless you’re doing HPC applications, is close enough to be unnoticeable.
Edit: I was originally going to omit this, as it’s propaganda from a vested interest, and includes no concrete numbers, but this blog entry from a product manager at QNX specifically mentions using microkernels in HPC problem spaces, which I thought was interesting, so I’m post-facto including it.