5 ms·
If you're on windows you can easily turn them off with inspectre from grc [1] [1] https://www.grc.com/inspectre.htm https://www.grc.com/inspectre.htm
by wnevets 6y ago
If you're on windows you can easily turn them off with inspectre from grc [1]
[1] https://www.grc.com/inspectre.htm https://www.grc.com/inspectre.htm
- martinesko36 6y agoDoes turning them off improve performance?
- coolspot 6y agoYes, very significantly, especially on old CPUs that don’t have hardware mitigations.
- wokkel 6y agoI've read the word "mitigation" so much (not only here, and not only you; so this comment is not directed at you personally) that I only hear doublespeak now: when people say mitigation I immediately think of a slab of concrete in the back of my car to compensate for not having any brakes installed. Please recognize for what it is: a design failure that is pampered upon. A mitigation is not a solution, it lessens the impact of the failure mode that was identified. Afaik, if the flushes and changes actually work, it is not a mitigation but a workaround: the failure mode cannot occur anymore. Mitigation sounds better than workaround though (and is probably the reason it was choosen).
- coolspot 6y agoOn Linux kernel >=5.1.13 you can add mitigations=off kernel boot parameter to turn off all mitigations. There are more granular parameters that are supported by all kernels implementing CPU mitigations: noibrs noibpb nopti nospectre_v2 nospectre_v1 l1tf=off nospec_store_bypass_disable no_stf_barrier mds=off mitigations=off https://unix.stackexchange.com/questions/554908/disable-spectre-and-meltdown-mitigations https://unix.stackexchange.com/questions/554908/disable-spec...
- danielheath 6y agoI have a test suite that went from 19 minutes to 8 with mitigations=off
- bildung 6y agowhich CPU?
- danielheath 6y agoThreadripper, 12-core 2920X
- jmnicolas 6y agoIt looks like it doesn't work on my PC: if I run it with elevated privileges and toggle off protections, they're back on when I restart the app.
- Royi 6y agoI don't think it turns off all mitigations. Only few of them.
- BunsanSpace 6y agoI don't think so. I do lots of compiling at work and our compiler hasn't changed in 5+ years. pre spectre my 8700k could do 20k lines/sec. Post spectre with mitigation it's about 10k, with them disabled it's about 15k. There's clearly been some under the hood changes to windows beyond these optional? changes.
- dmead 6y agodid you do a bios update or something you forgot about?
- BunsanSpace 6y agoNo bios update, but I wouldn't be surprised if windows shipped updated microcode or something.
- ncmncm 6y agoI am trying to understand this: you are compiling programs on Windows?
- BunsanSpace 6y agoYes, our application compiles it's own sub applications. It is win32 software.
- rizalp 6y agoAlternatively using registry edit: https://support.microsoft.com/en-us/help/4072698/windows-server-speculative-execution-side-channel-vulnerabilities https://support.microsoft.com/en-us/help/4072698/windows-ser...