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A comment on AMD lands Google, Twitter as customers with newest server chip. Parent comment

Re:AMD lands Google, Twitter as customers with newest server... by sq_ on Thursday August 08, 2019 @10:51AM (#20645105)
Does anyone know of any benchmarks that go through the full impacts for all of Intel’s hardware-level security issues?

I remember seeing the Linux kernel devs discussing some massive 10+% performance hits back around Meltdown/Spectre patch time, and I’m now wondering what the final impact has been.

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Re:AMD lands Google, Twitter as customers with newest server... by mrep on Thursday August 08, 2019 @11:07AM (#20645236)
10 percent? My teams RDS cpu usage spiked up by 40 percent after the initial patch [0].

[0]: https://m.imgur.com/a/khGxU

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Re:AMD lands Google, Twitter as customers with newest server... by hajile on Thursday August 08, 2019 @02:05PM (#20646947)
Epic Games saw their CPU usage double after applying the meltdown patch. Things have gotten quite a bit slower since then. Turns out flushing every time you switch into kernel space carries a massive impact if you are realtime with lots of network calls.

https://web.archive.org/web/20180106011413/https://www.epicg...

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Re:AMD lands Google, Twitter as customers with newest server... by sq_ on Thursday August 08, 2019 @11:21AM (#20645369)
Oh wow. That's a lot worse than I'd expected. Intel really royally screwed up, especially since so much of their current optimization relies on the same hardware functionality that makes these side-channel attacks possible.
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Re:AMD lands Google, Twitter as customers with newest server... by msh on Thursday August 08, 2019 @02:05PM (#20646950)
What is RDS short for?
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Re:AMD lands Google, Twitter as customers with newest server... by mrep on Thursday August 08, 2019 @02:15PM (#20647044)
Amazon web services relational database service: https://aws.amazon.com/rds/
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Re:AMD lands Google, Twitter as customers with newest server... by okanesen on Thursday August 08, 2019 @11:06AM (#20645218)
I don't know about full pre and post benchmarks but there is the latest benchmark from Phoronix which benchmarks the latest Spectre "SWAPGS" mitigations [0].

[0]: https://www.phoronix.com/scan.php?page=article&item=swapgs-s...

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Re:AMD lands Google, Twitter as customers with newest server... by toast0 on Thursday August 08, 2019 @01:26PM (#20646501)
The impacts really depend on your use case. The mitigations make each context switch have a much higher fixed cost.

If you're doing something that's syscall heavy, you're going to see a big negative difference. If it's something that's CPU heavy without making many syscalls, you're not going to see a lot of difference.

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