News

Intel Describes Server Slowdowns from Meltdown and Spectre Patches

• By Kurt Mackie
• 01/18/2018

Intel Corp. this week offered a progress report on the state of its firmware updates to address the widespread problems of potential Meltdown and Spectre attacks, while also providing a description of the server performance hits that could result from applying those patches.

Intel has now released firmware updates for "90 percent of Intel CPUs introduced in the past five years," according to Navin Shenoy, executive vice president and general manager of Intel's Data Center Group, in a Jan. 17 announcement. Intel's goal is to release fixes for all of its CPUs produced in the past five years by the end of this month. Its next plan is to issue firmware updates for older Intel chips.

Intel is still looking into a reboot problem that it earlier indicated may have affected "a few customers" using Broadwell or Haswell CPUs after they applied Intel's firmware fixes. The reboot issue, though, is also affecting other Intel CPUs, Shenoy noted this week:

As part of this, we have determined that similar [reboot] behavior occurs on other products in some configurations, including Ivy Bridge-, Sandy Bridge-, Skylake-, and Kaby Lake-based platforms. We have reproduced these issues internally and are making progress toward identifying the root cause. In parallel, we will be providing beta microcode to vendors for validation by next week.

Typically, Intel provides its firmware updates to its OEM computer-maker partners for testing before those updates become available to the public via the OEM. Operating system makers also are releasing patches to address the threats, and both types of patches should be applied. The problems affect both Windows- and Linux-based machines, including Apple products.

Intel this week also talked about the performance slowdown effects that likely will result after applying updates to address the Meltdown and Spectre attack methods. Shenoy particularly focused on Intel's server slowdown findings.

Intel's server test results used the 25 Intel Xeon Platinum 81xx Series, which appears to be one of Intel's higher-end server CPUs. This "Skylake" processor-based CPU is part of the Xeon Scalable line, with support for 28 cores, and is priced in the $10,000 range, according to an Intel spec sheet.

The firmware updates resulted in the following server performance effects, according to Intel:

• 0 percent to 2 percent slowdown for "industry-standard measures of integer and floating point throughput, Linpack, STREAM, server-side Java and energy efficiency benchmarks," which mostly applies to "enterprise and cloud customers."
• 4 percent slowdown for "an online transaction processing (OLTP) benchmark."
• 18 percent throughput decrease for the "FlexibleIO" storage benchmark when the CPU was stressed at 100 percent (it just showed a 2 percent slowdown effect with "a 70/30 read/write model").
• Up to 25 percent slowdown on its "Storage Performance Development Kit (SPDK) tests" for iSCSI using a single core, but there was no slowdown effect using "SPDK vHost."

Intel has repeatedly advised that the performance slowdowns from the updates will vary depending on the workloads that are run. The company is currently working with its partners to produce "other mitigations options that could yield less impact," Shenoy indicated.

Last week, Microsoft confirmed the system slowdowns from the Meltdown and Spectre patches and also indicated that a "more significant performance impact" would occur for server workloads.

Intel has tended to downplay the slowdown effects from firmware patches ever since the Meltdown and Spectre problems came into the public sphere earlier this month. In announcement last week regarding client effects, Intel contended that "we expected our performance impact should not be significant for average computer users" after its updates get applied to PCs using Intel Core processors.

On the client side, Intel reported seeing a 6 percent slowdown on Windows 7 machines using Intel sixth-generation processors, based on the SYSMark2014SE benchmark. A similar 6 percent result was seen with eighth-generation Intel chips, Intel reported.