Intel discusses Cascade Lake at Hot Chips – Spectre Mitigations and Performance

Intel discusses Cascade Lake at Hot Chips - Spectre Mitigations and Performance

Intel discusses Cascade Lake at Hot Chips – Spectre Mitigations and Performance

Back in March, Intel CEO (now former Intel CEO), Brian Krzanich, announced that the company would start shipping processors with Spectre hardware mitigations later this year, in-silicon fixes that will patch these exploits at their source. 

At Hot Chips 2018, Intel has confirmed that Cascade Lake will be one of their first chips to implement mitigations for “Side-Channel” attack methods, though some variants will still require patching at an OS/VMM level. 

The downside of today’s Spectre mitigations is their performance impact, with Intel’s latest hardware-based fixes lowering the harmful effects of their side-channel remedies. Sadly, Intel has not commented on how much these performance losses have been reduced.  

Spectre Variants 2, 3 and 5 now have in-silicon/hardware-based fixes, though Spectre Variant 2 will still require OS-level mitigations. Even so, this hardware fix should reduce the performance impact of these software fixes. Spectre Variant 3a and 4 will still need firmware fixes, with only Variant 4 requiring additional OS/VMM or runtime fixes. Spectre Variant 1 has no hardware/firmware fixes. 

Intel plans to add additional Side-Channel mitigations to their future processor designs, further hardening their resistance fo Spectre-like attacks.  

Intel discusses Cascade Lake at Hot Chips - Spectre Mitigations and Performance

With Cascade Lake, Intel plans to offer the same cache sizes, core counts and I/O speeds as their 1st Generation Skylake-based Xeon Scalable processors, with enhancements coming in the form of process tuning, frequency boosts and “targeted performance improvements”. 

Cascade Lake has been optimised for specific tasks thanks to the addition of several new instructions, many of which are designed to make use of the architecture’s AVX-512 computing capabilities. These instructions are designed to improve Intel’s Deep Learning performance. 

Another addition to Cascade Lake is hardware support for Intel Optane DIMMs, which will allow system manufacturers to create systems with up to six DDR4 memory modules and six optane DIMMs at the same time, which equates to 128GB of DRAM and 512GB of Optane per channel, which is a total of 3840GB per CPU socket. The addition of Optane support will be extremely beneficial for servers which make use of huge databases, offering DRAM-like latencies and high-speed SSD-like speeds. 

  
Intel discusses Cascade Lake at Hot Chips - Spectre Mitigations and Performance

 

While Cascade Lake appears to be like Skylake-X in many regards, Intel has refined their designs in several directions to offer increased performance levels. Sadly, to some users, Cascade Lake will appear to be a higher-clocked version of Skylake-X with Spectre fixes, though that undersells the impact of both Optane and Intel’s new Deep Learning instruction set support, which will be extremely beneficial to specific users. 

You can join the discussion on Intel’s Cascade Lake CPU architecture on the OC3D Forums.Â