Meltdown's Impact on Storage Performance - Really an Issue?

Subject: Storage | January 5, 2018 - 08:45 PM |
Tagged: RS4, RS3, patch, meltdown, KB4056892, cpu, 960 EVO, 900P, 850 EVO

While the Meltdown announcements and patches were in full swing, I was busily testing a round of storage devices to evaluate the potential negative impact of the Meltdown patch. Much of the testing we've seen has come in the form of Linux benchmarks, and today we saw a few come out on the Windows side of things. Most of the published data to date shows a ~20% performance hit to small random accesses, but I've noted that the majority of reviewers seem to be focusing on the Samsung 950/960 series SSDs. Sure these are popular devices, but when evaluating changes to a storage subsystem, it's unwise to just stick with a single type of product.

Test conditions were as follows:

  • ASUS Prime Z270-A + 7700K
    • C-States disabled,  no overclock.
    • ASUS MCE disabled, all other clock settings = AUTO.
  • SSDs:
    • Intel Optane 900P 480GB (Intel NVMe driver)
    • Samsung 960 EVO 500GB (Samsung NVMe driver)
    • Samsung 850 EVO 500GB (Intel RST driver)
  • Conditioning:
    • NTFS partition.
    • 16GB test file. Sequential conditioning.
    • Remainder of SSD sequentially filled to capacity.

The first results come from a clean Windows Redstone 3 install compared to a clean Windows 10 Redstone 4 (build 17063), which is a fast ring build including the Meltdown patch:

KASLR-IRQ2.png

The 960 EVO comes in at that same 20% drop seen elsewhere, but check out the 850 EVO's nearly 10% *increase* in performance. The 900P pushes this further, showing an over 15% *increase*. You would figure that a patch that adds latency to API calls would have a noticeable impact on a storage device offering extremely low latencies, but that did not end up being the case in practice.

Since the 960 EVO looked like an outlier here, I also re-tested it using the Microsoft Inbox NVMe driver, as well as by connecting it via the chipset (which uses the Intel RST driver). A similar drop in performance was seen in all configurations.

The second set of results was obtained later, taking our clean RS3 install and updating it to current, which at the time included the Microsoft roll-up 01-2018 package (KB4056892):

KASLR-IRQ2-.png

Note that the results are similar, though Optane did not see as much of a boost here. It is likely that some specific optimizations have been included in RS4 that are more beneficial to lower latency storage devices.

As a final data point, here's what our tests look like with software polling implemented:

KASLR-POLL2.png

The above test results are using an application method that effectively bypasses the typical interrupt requests associated with file transfers. Note that the differences are significantly reduced once IRQs are removed from the picture. Also note that kernel API calls are still taking place here.

Well there you have it. Some gain and some lose. Given that a far lower latency device (900P) sees zero performance hit (actually gaining speed), I suspect that whatever penalty associated with Meltdown could be easily optimized out via updates to the Windows Inbox and Samsung NVMe drivers.

Intel Optane on Linux

Subject: Storage | November 24, 2017 - 04:59 PM |
Tagged: Optane, Intel, linux, 900P, Ubuntu 17.10

Phoronix installed an Optane 900P SSD into their AMD EPYC system to test the performance the new drive provides running under Ubuntu.  Their results were very similar to Al's, showing that this fairly expensive 280GB SSD can justify its premium price by leaving the competition in the dust.  The testing suite they used is quite different from the one here at PCPer but the proof that Optane gets along well with Linux is indisputable.

image.php_.jpg

"At the end of October Intel released the Optane 900P solid-state drive as their new ultra high-end performance SSD. Windows reviews have been positive, but what about using the Optane 900P on Linux? It's working well and delivers stunning NVMe SSD performance."

Here are some more Storage reviews from around the web:

Storage

Source: Phoronix
Subject: Storage
Manufacturer: Intel

Introduction, Specifications and Packaging

Introduction:

It’s been two long years since we first heard about 3D XPoint Technology. Intel and Micron serenaded us with tales of ultra-low latency and very high endurance, but when would we have this new media in our hot little hands? We got a taste of things with Optane Memory (caching) back in April, and later that same month we got a much bigger, albeit remotely-tested taste in the form of the P4800X. Since April all was quiet, with all of us storage freaks waiting for a consumer version of Optane with enough capacity to act as a system drive. Sure we’ve played around with Optane Memory parts in various forms of RAID, but as we found in our testing, Optane’s strongest benefits are the very performance traits that do not effectively scale with additional drives added to an array. The preferred route is to just get a larger single SSD with more 3D XPoint memory installed on it, and we have that very thing today (and in two separate capacities)!

DSC01118.jpg

Rumor Central:

You might have seen various rumors centered around the 900P lately. The first is that the 900P was to supposedly support PCIe 4.0. This is not true, and after digging back a bit appears to be a foreign vendor mistaking / confusing PCIe X4 (4 lanes) with the recently drafted PCIe 4.0 specification. Another set of rumors centered around pre-order listings and potential pricing for the 280 and 480 GB variants of the 900P. We are happy to report that those prices (at the time of this writing) are way higher than Intel’s stated MSRP's for these new models. I’ll even go as far as to say that the 480GB model can be had for less than what the 280GB model is currently listed for! More on that later in the review.

Specifications:

Performance specs are one place where the rumors were all true, but since all the folks had to go on was a leaked Intel press deck slide listing figures identical to the P4800X, we’re not really surprised here.

specs.png

Lots of technical stuff above, but the high points are <10us typical latency (‘regular’ SSDs run between 60-100us), 2.5/2.0 GB/s sequential reads/writes, and 550k/500k random read/write performance. Yes I know, don’t tell me, you’ve seen higher sequentials on smaller form factor devices. I agree, and we’ve even seen higher maximum performance from unreleased 3D XPoint-equipped parts from Micron, but Intel has done what they needed to do in order to make this a viable shipping retail product, which likely means sacrificing the ‘megapixel race’ figures in favor of offering the lowest possible latencies and best possible endurance at this price point.

Packaging:

DSC05837.jpg

Packaging is among the nicest we’ve seen from an Intel SSD. It actually reminds me of how the Fusion-io ioDrives used to come.

RSI Star Citizen Sabre Raven Ship.jpg

Also included with the 900P is a Star Citizen ship. The Sabre Raven has been a topic of gossip and speculation for months now, and it appears to be a pretty sweet looking fighter. For those unaware, Star Citizen is a space-based MMO, and with a ‘ship purchase’ also comes a license to play the game. The Sabre Raven counts as such a purchase and apparently comes with lifetime insurance, meaning it will always be tied to your account in case it gets blown up doing data runs. Long story short, you get the game for free with the purchase of a 900P.

Read on for our full review of the Intel Optane SSD 900P (in both capacities)!