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The Spectre/Meltdown Performance Impact On Linux 4.20, Decimating Benchmarks With New STIBP Overhead

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  • #41
    Originally posted by ryao View Post

    The problem with this mentality is that it risks ignoring a situation where a fix is later found to be important.

    If you run a web browser, Skype, games from steam or even steam, you are basically executing code that is a vector through which malware can gain a foothold to use a local vulnerability. It is wrong to think of an exploit by itself as being not serious from it requiring X thing because there will be an exploit that is also considered not serious that gives X thing. The power of chained exploits is quite something. Here is an article showing the power of chained exploits:
    Spectre/Meltdown vulnerabilities have been known for almost a year already. Not a single actual exploit has been found yet.

    Still, 100% of users must suffer tremendously because in theory someone could be hacked.

    Also, tell me how home users could be theoretically hacked using these vulnerabilities. Chaining and everything - I'm all ears.

    There's a load of BS going on in this thread and people mindlessly "like" certain posts without understanding shit about the issue at hand.

    Originally posted by ryao View Post

    The mainline Linux kernel developers do not need to provide such a way, although they do anyway. It dies not require recompiling your kernel. It is a commandline flag. If you aren’t concerned about the other Spectre issues that affect AMD, you might as well ignore Spectre v1 too.
    Again BS on top of BS. Certain vulnerabilities are baked-in during compilation using GCC flags and you cannot even disable them using `make config`, you there's no way you can disable them using boot arguments.
    Last edited by birdie; 18 November 2018, 06:48 AM.

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    • #42
      Originally posted by creative View Post

      As apposed to a non-Ti?
      Whatever that has sweet performance push will be doomed as more vulnerable They were demonstrating it using OpenGL and CUDA on nVidia hardware

      New attacks on graphics processors endanger user privacy


      Hackers can use the graphics processing unit to spy on web activity, steal passwords, and break into cloud-based applications
      Last edited by dungeon; 18 November 2018, 06:52 AM.

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      • #43
        dungeon not surprised, nearly all technology is not safe it seems. Not going to freak out about it though. Seems like the bulk of what hackers are really going after these days is iot stuff. There is a much bigger payoff for that in iot.

        Just because something has been demonstrated, does not mean its a high priority for the unscrupulous.
        Last edited by creative; 18 November 2018, 07:17 AM.

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        • #44
          Originally posted by schmidtbag View Post
          AMD's IPC was never really that far behind, it's just that Intel for a long while got a big performance lead due to these vulnerabilities.
          Repeating the same thing isn't going to turn it into fact.

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          • #45
            Originally posted by creative View Post
            schmidtbag Windows is fine. Been gaming on it for the past three weeks straight.
            It's been known from the start that these mitigations do not effect gaming, it's sever side where the performance drops. So unless you've been playing some cluster/virtual/data centre based you probably wont have seen issues

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            • #46
              Originally posted by phoronix View Post
              Phoronix: The Spectre/Meltdown Performance Impact On Linux 4.20, Decimating Benchmarks With New STIBP Overhead

              As outlined yesterday, significant slowdowns with the Linux 4.20 kernel turned out to be due to the addition of the kernel-side bits for STIBP (Single Thread Indirect Branch Predictors) for cross-HyperThread Spectre Variant Two mitigation. This has incurred significant performance penalties with the STIBP support in its current state with Linux 4.20 Git and is enabled by default at least for Intel systems with up-to-date microcode. Here are some follow-up benchmarks looking at the performance hit with the Linux 4.20 development kernel as well as the overall Spectre and Meltdown mitigation impact on this latest version of the Linux kernel.

              http://www.phoronix.com/vr.php?view=27093
              The glibc benchmarks are unreliable. Don't trust them.

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              • #47
                Originally posted by Weasel View Post
                Repeating the same thing isn't going to turn it into fact.
                Look, I understand you're a diehard Intel fan, but you keep posting quotes like that which make no sense at all. In what context is something being repeated? What is "the same thing"? What are you disputing as fact?

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                • #48
                  Originally posted by creative View Post
                  For my setup I have seen no real noticeable performance crappout pre meltdown spectre vs post all the patches. I run the latest games as well. I feel really unaffected by it but interesting to read about and interesting how people are perceiving it. Perception is an interesting thing.
                  Well yeah - I figured that was the case. I was pretty certain that the perceived performance would be nearly indistinguishable on modern games with hardware like yours. But that doesn't actually tell us whether or not Windows has the same performance losses, in a numbers perspective.

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                  • #49
                    Originally posted by birdie View Post

                    Spectre/Meltdown vulnerabilities have been known for almost a year already. Not a single actual exploit has been found yet.

                    Still, 100% of users must suffer tremendously because in theory someone could be hacked.

                    Also, tell me how home users could be theoretically hacked using these vulnerabilities.

                    There's a load of BS going on in this thread and people mindlessly "like" certain posts without understanding shit about the issue at hand.



                    Again BS on top of BS. Certain vulnerabilities are baked-in during compilation using GCC flags and you cannot even disable them using `make config`, you there's no way you can disable them using boot arguments.
                    https://www.techrepublic.com/article...ns-of-malware/

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                    • #50
                      Originally posted by schmidtbag View Post
                      Look, I understand you're a diehard Intel fan, but you keep posting quotes like that which make no sense at all. In what context is something being repeated? What is "the same thing"? What are you disputing as fact?
                      I'm talking about the nonsense people spread about "Intel cut corners that's why they have higher IPC than AMD". Repeating that, in various forms, is not going to turn it into a fact, sorry.

                      This has nothing to do with being an Intel fan or not, I would say the same about AMD, it's just logic. FYI I like Zen as a uarch, not for the same reasons most people look at, but the underlying arch. You kind of have to be an assembly programmer to get why.
                      Last edited by Weasel; 18 November 2018, 04:01 PM.

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