iPhone update for Meltdown-Spectre: before/after performance benchmarks • Hacker News Board

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#51

Post by dogma1138 » Wed, Jan 10, 2018, 8:19 PM UTC

bfrog wrote: post #9

FBISurveillance wrote: post #2

I've went through Denial, Anger, Bargaining, and now in an Acceptance stage after taking up to 31% performance hit on some of services managed by my team. Worst case has been Elasticsearch so far with our load pattern, taking that 31% hit. Oh well, too bad, enjoying the ride.

Time to switch to an Epyc host?

AMD is vulnerable to Spectre and are not fixing variant 2 because it’s “near zero risk”.

By near zero risk they mean that no one has yet reversed engineered their branch prediction which is required to effectively exploit it.

Give it sometime and the BTI patch would have to be enforced on AMD CPUs also.

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#52

Post by dogma1138 » Wed, Jan 10, 2018, 8:20 PM UTC

TheSithMaster wrote: post #43

ucha wrote: post #34

I just ran GeekBench 4 on my iPhone X on iOS 11.2.2 vs 11.2.1. Single core: 4239 vs 4241 Multi-core: 10081 to 10203 So no difference.

The test done here was comparing 11.2.2 vs 11.1.2

Isn’t 11.2.1 the battery patch?

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#53

Post by bitmapbrother » Wed, Jan 10, 2018, 8:21 PM UTC

Something isn't right with his benchmarks.

My iPhone 6 benchmarks:

Geekbench test taken on Dec 18, 2017 with iOS 11.2

Single Core: 1566

Multi-Core: 2697

Geekbench test taken on Jan 10, 2018 with iOS 11.2.2

Single Core: 1551

Multi-Core: 2675

Percentage slowdown:

Single Core: 0.96%

Multi-Core: 0.82%

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#54

Post by jpambrun » Wed, Jan 10, 2018, 8:23 PM UTC

ucha wrote: post #34

I just ran GeekBench 4 on my iPhone X on iOS 11.2.2 vs 11.2.1. Single core: 4239 vs 4241 Multi-core: 10081 to 10203 So no difference.

Does GeekBench 4 make a lot of syscalls? My understanding is that these are the most affected by the mitigations.

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#55

Post by stefanwlb » Wed, Jan 10, 2018, 8:23 PM UTC

An the apple police bring down another anti-applr website. Also, the slow down is related more to the battery = slow down than the new meltdown scare. Amazing, they reduced 50% of the CPU power so you don't have "battery" issues haha

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#56

Post by TheSithMaster » Wed, Jan 10, 2018, 8:23 PM UTC

dogma1138 wrote: post #52

TheSithMaster wrote: post #43

Earlier quoted context omitted.

The test done here was comparing 11.2.2 vs 11.1.2

Isn’t 11.2.1 the battery patch?

You are correct, it appears to be that "patch".

Source: https://discussions.apple.com/thread/8211392

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#57

Post by viraptor » Wed, Jan 10, 2018, 8:23 PM UTC

Ok, I'm sceptical about the results. The reason is that there doesn't seem to be a massive difference between the tests. Since this fix is about speculative exec, why would it affect crypto code which is very register based and branchless as much as sqlite which is full of branches and memory/storage based? Why would it affect AES which is hardware accelerated as much as integer processing which is not?

I'm not saying this is impossible - maybe there's something that I'm missing. But it just doesn't add up at the moment. I'd love a more detailed / repeatable test.

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#58

Post by fulafel » Wed, Jan 10, 2018, 8:25 PM UTC

bluedino wrote: post #17

>> a significant decrease in performance on the iPhone 6 up to 50% Something's up. I updated my 6S yesterday and have noticed zero in performance changes or battery loss. Still plenty of bugs though, I was reading an email and the 'flag/file/trash/reply/new' bar totally went away. At least the touchscreen hasn't gone unresponsive, causing me to have to hit sleep/wake to toggle it back on. Maybe they finally fixed tha…

6 and 6S have different CPUs.

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#59

Post by MBCook » Wed, Jan 10, 2018, 8:27 PM UTC

euph0ria wrote: post #14

I wonder how much extra revenue this will bring to AWS/GCP etc selling more instances to cover the performance loss on servers?

It’s a hit on AWS users, that means it’s also a hit for Amazon themselves.

They’ll sell more servers, but they just lost 10% (or whatever) of their headroom all around the world.

Re: iPhone update for Meltdown-Spectre: before/after performance benchmarks

#60

Post by jasonlotito » Wed, Jan 10, 2018, 8:27 PM UTC

bitmapbrother wrote: post #53

Something isn't right with his benchmarks. My iPhone 6 benchmarks: Geekbench test taken on Dec 18, 2017 with iOS 11.2 Single Core: 1566 Multi-Core: 2697 Geekbench test taken on Jan 10, 2018 with iOS 11.2.2 Single Core: 1551 Multi-Core: 2675 Percentage slowdown: Single Core: 0.96% Multi-Core: 0.82%

Do you have Geekbench test with iOS 11.1.2 instead of 11.2?