This is especially relevant if you're running in the cloud.
We've recently run into slow performance with gettimeofday on Xen systems, such as EC2 (see: https://blog.packagecloud.io/eng/2017/03/08/system-calls-are...) This hits particularly hard if you're running instrumented code. Switching the clocksource from xen to tsc seems to help and we're still evaluating the ramifications of doing so (various sources including the above seem to suggest that tsc is unsafe and prone to clock skew, but others suggest that it's ok on more modern processors.)
We've recently run into slow performance with gettimeofday on Xen systems, such as EC2 (see: https://blog.packagecloud.io/eng/2017/03/08/system-calls-are...) This hits particularly hard if you're running instrumented code. Switching the clocksource from xen to tsc seems to help and we're still evaluating the ramifications of doing so (various sources including the above seem to suggest that tsc is unsafe and prone to clock skew, but others suggest that it's ok on more modern processors.)