The image didn't show up for me, here is a direct link for anyone with the same problem: https://lh6.googleusercontent.com/MwzsHRXQLVbmJ3pusNuGwn0ZQV...
CPU Usage Differences After Applying Meltdown Patch at Epic Games
111–120 of 296 posts
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#112Graph says pretty clearly the patch is 60-70% slower! or 2.5-3x hardware costs. I wonder which CPU family this is?
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#113Earlier quoted context omitted.
Real data like this post are more useful than more benchmarks.
They are benchmarks, just not microbenchmarks. Actual application performance is the gold standard for benchmarks. https://en.wikipedia.org/wiki/Benchmark_(computing)#Types_of...
> They are benchmarks, just not microbenchmarks. Actual application performance is the gold standard for benchmarks.
This depends on your intended purpose of the benchmark. If you want to evaluate performance of a whole system, sure. But one often does benchmarks to find parts of the system that are critical to performance so that you can do further optimizations or do change in the software architecture to avoid these critical performance hotsports. For this case other benchmarks that allow an easy fine-grained interpretation of the data are surely better.
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#114Maybe off-topic: Is formal verification viable anywhere in CPU logic design? Also, could any existing "CPU static analyzers" have caught the issue that caused Meltdown? Edit: It looks like the answer to the first is a definite yes.
Spitballing, but you'd have to prove that either no side channels exist, or that the information leaked by side channel(s) is indistinguishable from random noise, which I believe is an area of ongoing research.
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#115Pretty much what I predicted here: https://news.ycombinator.com/item?id=16054674 > Sounds like servers handling lots of small UDP packets would be hit pretty hard.
Since they describe this as log-in issues, should we expect that to be a server using lots of UDP? Or do you think that the log-in service is hemmed in by the load on the game servers?
No, login in Fortnite is over 443 and it uses normal HTTPS.
It also uses HTTPs to load a lot of other data such as server data, friends list, chat etc.
Unreal Engine comes with a version of chromium built in which is used for many in game things like social tabs, news, and in game purchases these all work over HTTP/S.
Game data is sent over 5222 TCP.
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#116Earlier quoted context omitted.
Thank you for the explanation, and especially for being non-snarky, which unfortunately seems to be getting rarer and rarer on this forum.
> which unfortunately seems to be getting rarer and rarer on this forum. If this isn't unnecessarily "snarky" itself, then what is it? snarky : (of a person, words, or a mood) sharply critical; cutting; snide.
That wasn't snarky because it was only mildly critical. Since it was mild, it also wasn't cutting. Lastly, it was not derogatory or mocking in an indirect way and so it was not snide either.
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#117Earlier quoted context omitted.
I wouldn't be so sure of that. They at least run Javascript through their web browser.
The Nintendo Switch generally only allows white-listed pages. So the attack vector is pretty small. The other consoles, yes, should be possible. But I think not too many people use their consoles for browsing.
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Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#118Maybe off-topic: Is formal verification viable anywhere in CPU logic design? Also, could any existing "CPU static analyzers" have caught the issue that caused Meltdown? Edit: It looks like the answer to the first is a definite yes.
Formal verification of what? You can only verify properties you've thought of, and no-one conceived of this particular 'feature' causing issues like this until now. So I don't think formal verification would have helped: if anyone was in a position to realise the issue was worth verifying, they'd have been able to raise it without formal verification too.
Presumably of isolation features. I'm sure everyone knew what side channel attacks were and knew that formal verification could've helped find bugs in isolation. They just chose not to do it, because it's only important for high-assurance, not for your regular insecure linux/bsd/windows. And I'm sure they are not going to bother with verification even after everything.
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#119The image didn't show up for me, here is a direct link for anyone with the same problem: https://lh6.googleusercontent.com/MwzsHRXQLVbmJ3pusNuGwn0ZQV...
Sorry to ask, but does anyone have a third mirror? Neither are working for me and I really am interested in seeing this image.
Re: CPU Usage Differences After Applying Meltdown Patch at Epic Games
#120The image didn't show up for me, here is a direct link for anyone with the same problem: https://lh6.googleusercontent.com/MwzsHRXQLVbmJ3pusNuGwn0ZQV...
Sorry to ask, but does anyone have a third mirror? Neither are working for me and I really am interested in seeing this image.
