Search Infra (and Ads for that matter) is an extreme case. Google Search might be one of the worlds most highly tuned infrastructure projects: a marriage of code and hardware design to maximize performance, scoring, relevance and ultimately ROI.
Before we had custom machine types (November 2015 GA), we wouldn't have been remotely close to what they needed. I'm not even sure we've had anyone evaluate the amount of overhead KVM adds in either latency or throughput.
tl;dr: Don't let Search be your "not until they do it". We've got folks in Chrome, Android, VR, and more building on top of Cloud (as well as much of our internal tooling being on App Engine specifically).
Before we had custom machine types (November 2015 GA), we wouldn't have been remotely close to what they needed. I'm not even sure we've had anyone evaluate the amount of overhead KVM adds in either latency or throughput.
tl;dr: Don't let Search be your "not until they do it". We've got folks in Chrome, Android, VR, and more building on top of Cloud (as well as much of our internal tooling being on App Engine specifically).