3 ms·
This isn't the fix with the 5% quoted performance loss (that one clears all of TLB on every syscall), I don't think this is as costly. But it's certainly not fr
by revelation 9y ago
This isn't the fix with the 5% quoted performance loss (that one clears all of TLB on every syscall), I don't think this is as costly. But it's certainly not free and it's certainly not clean.
I'm disappointed Intel didn't bother to test the performance impact of this and report it in the patchset. Benchmarks are ordinarily expected with something like this (very hot paths they are changing), and they did have 6 months..
- userbinator 9y agoThis is worse, far worse --- it basically disables prediction for indirect jumps and calls, plus adds another few extra clock cycles to each one of those for the "retoline" instruction sequence.
- PhantomGremlin 9y agoI'm disappointed Intel didn't bother to test the performance impact of this and report it in the patchset. You should be disappointed that they didn't report it. But I'd be willing to bet every last dollar of my net worth that Intel has done very extensive performance testing. I'd venture that the results are far too embarrassing to report.
- barkingcat 9y agoYup this for sure. They probably ran the performance test bench thousands of times, and only then released it with the PR department fully briefed about how bad it was going to be.