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Haswell and early Broadwell had a bug in its transactional memory extensions so serious that the microcode "fix" simply permanently disabled the instructions.
by msbarnett 10y ago
Haswell and early Broadwell had a bug in its transactional memory extensions so serious that the microcode "fix" simply permanently disabled the instructions.
CPU errata like this aren't uncommon.
- m45t3r 10y agoWhile those are the most remembered bugs, almost every CPU have some kinda of CPU errata that can lock up the system in really weird and specific ways. For example, my Intel Ivy Bridge CPU running Linux: $ dmesg | grep -i microcode [ 0.000000] microcode: microcode updated early to revision 0x1c, date = 2015-02-26 [ 1.415548] microcode: sig=0x306a9, pf=0x10, revision=0x1c [ 1.415665] microcode: Microcode Update Driver: v2.2. The fact that most users does not hit those bugs is because modern OS already patches those microcode before execution (like the case above). Of course, if AMD can't fixes those bugs without performance regressions (remember the infamous TLB Bug from earlier Phenoms?) it can be pretty bad. However I don't think the majority of users needs to be too cautious about it.
- yuhong 10y agoSome of which are quite serious: http://yuhongbao.blogspot.ca/2015/06/why-your-core-2-processor-appear-to-not.html http://yuhongbao.blogspot.ca/2015/06/why-your-core-2-process...