I don't know where 1-2% comes from, but for many scale production workloads I studied it was so close to 0% that it was tough to measure beyond noise on the cloud. That's not to say that 1-2% is wrong, but that it's likely someone's workload and other people see less.
Helping people find ~30-3000% perf wins, helping debugging and automated bug reports, is huge. For some sites it may be like 300 steps forward, one step back. But it's also not the end of the road here. Might we go back to frame pointer ommision one day by default if some other emerging stack walkers work well in the future for all use cases? It's a lot of ifs and many years away, and assumes a lot of engineering work continues to be invested for recoving a gain that's usually less than 1%, but anythings possible.
There's a couple of problems with an apt reinstall. One is that people often don't work on performance until the system is melting down -- many times I've been handed an issue where apt is dreadfully slow due to the system's performance issue and just installing a single package can take several minutes -- imagine reinstalling everything, it could turn the outage into over an hour! The other is I'd worry that reinstalling everything introduces so many changes (updating library versions) that the problem could change and you'd have no idea which package update changed it. If there was such an apt reinstall command, I know of large sites (with experience with frame pointer overheads) that would run it and then build their BaseAMI so that it was the default. Which is what Ubuntu is doing anyway.
That's just the same handwavey reason as given in the article. Where is the evidence that this will actually result in any significant amounts of optimization that wouldn't be possible without making everything (slightly) slower for end users.
Comments
I don't know where 1-2% comes from, but for many scale production workloads I studied it was so close to 0% that it was tough to measure beyond noise on the cloud. That's not to say that 1-2% is wrong, but that it's likely someone's workload and other people see less.
Helping people find ~30-3000% perf wins, helping debugging and automated bug reports, is huge. For some sites it may be like 300 steps forward, one step back. But it's also not the end of the road here. Might we go back to frame pointer ommision one day by default if some other emerging stack walkers work well in the future for all use cases? It's a lot of ifs and many years away, and assumes a lot of engineering work continues to be invested for recoving a gain that's usually less than 1%, but anythings possible.
There's a couple of problems with an apt reinstall. One is that people often don't work on performance until the system is melting down -- many times I've been handed an issue where apt is dreadfully slow due to the system's performance issue and just installing a single package can take several minutes -- imagine reinstalling everything, it could turn the outage into over an hour! The other is I'd worry that reinstalling everything introduces so many changes (updating library versions) that the problem could change and you'd have no idea which package update changed it. If there was such an apt reinstall command, I know of large sites (with experience with frame pointer overheads) that would run it and then build their BaseAMI so that it was the default. Which is what Ubuntu is doing anyway.
Eeven 0.1% scaled accross all users is a huge amount of wasted energy. You can profile without subjecting everyone to frame pointers.
Not nearly as much as the missed optimizations from not having this easily available.
[citation needed]
That's just the same handwavey reason as given in the article. Where is the evidence that this will actually result in any significant amounts of optimization that wouldn't be possible without making everything (slightly) slower for end users.
Right from the article. I find it a difficult subject, as a developer/poweruser I am happy to see framepointers. But I can not speak for others.