Thursday, January 04, 2018

Intel Meltdown Reshapes the x64 Computing Landscape

Finally, the picture has been set straight. Let me summarize.

1) The Intel Meltdown hole is on the galactic scale. You didn't see me jumping up about the Intel trust management bug, because that can be fixed in software. This Intel Meltdown hole is in the silicon logic. The Meltdown flaw is fatal, as it enables a small user application to silently read all system memory, including kernel memory and even kernel memory of another virtual machine, all without leaving any trace.

2) The OS fix for Meltdown is very costly, up to 50% performance hit. Worse, the hit increases with higher end hardware. If you use super expensive NVME drives, the percentage loss in performance will be bigger, as more context switches are need to trap into the kernel, where the Intel Meltdown flaw necessitates flush of the cache on XEON and i7 CPUs. Moreover, I am not sure that the OS fix such as KPTI completely solves the problem.

3) The future fix in the silicon will take Intel about a year. When that happens, I project that Intel's IPC (instructions per clock) be lower by about as much as 15%. Intel has taken all sorts of unsound shortcuts to get higher IPC, relying on the naive assumption that code behaves nicely. The Intel Core now has about 5% IPC advantage over the AMD ZEN architecture. That advantage will vaporize when Intel performs proper checks before speculative execution.

4) AMD has done a very good job in implementing valid execution logic and in security. Most signicantly, AMD is immune from the Meltdown, the most serious flaw that can be easily exploited by any script kiddie. AMD led the industry into x64 computing with its rock solid Opteron. With the disgraceful demise of the XEON, the AMD EPYC stands to be the only enterprise worthy x64 chip for a long time. The RyZEN desktop CPU is in fact an EPYC server CPU with enterprise features disabled. AMD means reliability, quality and security.

5) Financial projection: Intel's damages can hardly be underestimated, as class action lawsuits are looming from all angles from shareholder derivative, consumer, enterprise customer to indemnification. SEC may look into some of the insider trades. In addition to the loss of reputation and market share, how Intel compensates for the defective CPUs and loss of performance is unclear. Since the Intel Meltdown is a design flaw that can be avoided (as AMD did), Intel may be strictly liable for all damages caused by Meltdown.


Blogger PENIX said...

This is game over for Intel. Finally, the predictions that Sharikou made over a decade ago, are proven to be completely accurate.

4:50 PM, January 14, 2018  

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