Intel's roadmap for Optane SSDs with 1,000x performance • Hacker News Board

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#71

Post by chongli » Tue, Jun 14, 2016, 2:45 AM UTC

eloff wrote: post #64

nneonneo wrote: post #21

To be perfectly clear: the 1000x claim isn't about throughput , but latency . The graph in the article makes this clear: spinning drives have latencies on the order of 10ms, NAND flash about 10us, and DRAM about 1ns. The claim is that Optane will achieve latencies on the order of 10ns, or 1000x better than NAND. The on-stage benchmark shows a write throughput of about 2GB/s, which is a much more modest improvement ov…

DRAM does not have 1ns latency! On a 4ghz skylake chip you can access the L1 cache at 1ns. DRAM is going to be more in the range of 60(local)-100(remote) nanoseconds. Optane will likely be > 300ns latency from what I've heard, if you access it directly through the CPU memory controller via loads and stores, which is still very impressive.

When we talk about 1ns latency for DRAM we aren't talking about access latency, we're talking about CAS latency[0]. This is how fast the DRAM actually works. It doesn't include the rest of the overhead between the time the data is sent over the bus and the time it's loaded into a register and ready for an instruction to operate on it.

CAS latency for DDR3-3300 is less than 1/3ns, according to the article below. If Intel's new Optane memory can achieve addressing on the order of 10ns, it will be very competitive with DRAM, since all of other overhead along the data path ought to be similar.

[0] https://en.wikipedia.org/wiki/CAS_latency

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#72

Post by vitus » Tue, Jun 14, 2016, 3:36 AM UTC

chongli wrote: post #71

eloff wrote: post #64

Earlier quoted context omitted.

DRAM does not have 1ns latency! On a 4ghz skylake chip you can access the L1 cache at 1ns. DRAM is going to be more in the range of 60(local)-100(remote) nanoseconds. Optane will likely be > 300ns latency from what I've heard, if you access it directly through the CPU memory controller via loads and stores, which is still very impressive.

When we talk about 1ns latency for DRAM we aren't talking about access latency , we're talking about CAS latency [0]. This is how fast the DRAM actually works. It doesn't include the rest of the overhead between the time the data is sent over the bus and the time it's loaded into a register and ready for an instruction to operate on it. CAS latency for DDR3-3300 is less than 1/3ns, according to the article below. If…

This is actually slightly incorrect. You seem to be calculating as if the clock rate were 3300MHz, even though the listed number in DDR (double data rate) is actually double the actual clock rate (IIRC, for marketing reasons).

On top of that, the CAS latency is given in cycles -- the cited CAS latency for DDR3-3300 is 16 cycles. Multiplying # cycles by time per cycle yields a value closer to 9-10ns. Note that this is the "first word" latency in this table.

- The other thing you may be talking about is this "bit time", which looks like it's simply inverse throughput. It's very important not to conflate throughput with latency.

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#73

Post by astrodust » Tue, Jun 14, 2016, 3:37 AM UTC

nashashmi wrote: post #4

imperialdrive wrote: post #2

I just love this stuff! Storage minded for 20 years... all other tech aside, storage is what gets me up until sunrise researching... if 2017 sees this kind of tech, I'll be smitten :-D

Won't there come a time when 1000x speed increase will still be slow? The applications will mostly be on heavy data side like medical research and weather patterns, but it could also involve 3D photogrammetry taking in a trillion points.

Your average Instagram shot and filter involves more data processing power than NASA had in its entire supercomputer center in the 1960s.

What will the 2060 Instagram be?

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#74

Post by vitus » Tue, Jun 14, 2016, 3:55 AM UTC

jacquesm wrote: post #48

Joeri wrote: post #47

Earlier quoted context omitted.

SSD's haven't displaced drives for bulk data center storage because it's all about $/GB and although SSD's are getting cheaper, spinning disks got cheaper in the same way. Intel is not going to compete on price, but on performance. So rest assured that spinning disks will be with us for a while.

Bulk data is the key there, for many other use cases servers are already using SSDs and once the economies of scale will cause another order of magnitude decrease in cost I think spinning disks will be much more expensive in $/GB than SSDs. Chips are cheap, robust, quite dense and should have a much longer operating life than anything mechanical. The writing is on the platters.

Not just this; HDD technology has been stagnating, while SSD technology still has yet to reach its full potential. In the last five years, HDDs haven't really gotten cheaper (other than market returning to pre-flooding equilibrium). On the other hand, SSDs have gotten easily 4x cheaper in that same period of time.

Plus, since SSDs aren't using the latest process technology (as far as I'm aware), they still have a few more years of Moore's law ahead of them. Shrinking transistor size means increased density (and at lower cost, once you recoup the cost of the mask).

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#75

Post by Buge » Tue, Jun 14, 2016, 3:55 AM UTC

olavgg wrote: post #15

erik wrote: post #9

1,000x performance, but they are introducing it with a PCIe 3.0 x4 interface? That is suspicious. And then they are going to follow with a lower cost PCIe 3.0 x2 version? (That they still label as an Enthusiast / Workstation product?) I wonder if they are aggressively segmenting the market so that you have to pay a lot for the "enterprise" product to get the full performance. Or, alternatively, if the real world perf…

Basically on a PCIe 3.0 x4 maximum performance is 4000GB/s, in practice this is 3200-3500MB/s. With 4k random write, you will get maximum 800.000 to 875.000 iops per second. Consumer-grade SSD's barely manage to write 500-1000 iops when sending the ATA_CMD_FLUSH command unless they are lying which is really bad. Good read about consumer SSD performance: http://www.sebastien-han.fr/blog/2014/10/10/ceph-how-to-test...

You made a 3 order of magnitude jump. Is that a typo?

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#76

Post by todd8 » Tue, Jun 14, 2016, 4:03 AM UTC

nneonneo wrote: post #21

To be perfectly clear: the 1000x claim isn't about throughput , but latency . The graph in the article makes this clear: spinning drives have latencies on the order of 10ms, NAND flash about 10us, and DRAM about 1ns. The claim is that Optane will achieve latencies on the order of 10ns, or 1000x better than NAND. The on-stage benchmark shows a write throughput of about 2GB/s, which is a much more modest improvement ov…

To put these latency numbers in perspective 1ns is about 11 inches at the speed of light.

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#77

Post by jdub » Tue, Jun 14, 2016, 4:06 AM UTC

gpderetta wrote: post #46

nneonneo wrote: post #35

Earlier quoted context omitted.

10ns latency means that a file entry/inode/block is available just 10-30 CPU cycles after it is requested. Suddenly the 1000 CPU cycles spent dispatching the system call look very inefficient by comparison. Obsolete might not be the right term, but there is essentially no way that open/read/write can take proper advantage of this kind of low latency storage. We are going to need a new way to abstract and interface wi…

Or a way to make system calls faster, some sort of vdso with the ability to switch privilege level.

That's how __vsyscall works now.

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#78

Post by School-Cotton » Tue, Jun 14, 2016, 4:14 AM UTC

todd8 wrote: post #76

nneonneo wrote: post #21

To be perfectly clear: the 1000x claim isn't about throughput , but latency . The graph in the article makes this clear: spinning drives have latencies on the order of 10ms, NAND flash about 10us, and DRAM about 1ns. The claim is that Optane will achieve latencies on the order of 10ns, or 1000x better than NAND. The on-stage benchmark shows a write throughput of about 2GB/s, which is a much more modest improvement ov…

To put these latency numbers in perspective 1ns is about 11 inches at the speed of light.

Or three cycles on a typical desktop CPU.

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#79

Post by [deleted] » Tue, Jun 14, 2016, 4:19 AM UTC

zer00eyz wrote: post #43

jacquesm wrote: post #29

Earlier quoted context omitted.

It's a game changer either way, and it will be one more nail in the coffin of anything mechanical.

For consumer, and "online" hardware I fully agree, but were going to have tape for a long time to come. As a medium, for offline, offsite it still reigns king. Density, reliably, and durability remain high, vs platter based drives or SSD. I know of at least two companies that keep tape going for compliance reasons. At the end of each year, they do a pretty large archival snapshot, and send it off to storage. It will…

[deleted]

Re: Intel's roadmap for Optane SSDs with 1,000x performance

#80

Post by visarga » Tue, Jun 14, 2016, 5:48 AM UTC

ChuckMcM wrote: post #67

nneonneo wrote: post #21

To be perfectly clear: the 1000x claim isn't about throughput , but latency . The graph in the article makes this clear: spinning drives have latencies on the order of 10ms, NAND flash about 10us, and DRAM about 1ns. The claim is that Optane will achieve latencies on the order of 10ns, or 1000x better than NAND. The on-stage benchmark shows a write throughput of about 2GB/s, which is a much more modest improvement ov…

Ok, a couple of things. First, I found it really amazing at how convoluted Intel plotted their numbers on that latency graph so that it would "Up and to the right" which everyone "knows" is good. The second thing is that Intel has been claiming multiple GB/second of throughput as well. They really do believe this will be a replacement for DRAM on some platforms. As in you read into your L3 case from this stuff and yo…

> Quite a different experience than what we have today.

For example, I only have to wait at most one second for an app to load, if it's not already open and minimized. It's comparable to the time it takes me to click a button. And my computer is rebooted only once every few months, so it's always up.

This improvement will be more meaningful for random access database operations.