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How “latency numbers everybody should know” decreased from 1990–2020

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Re: How “latency numbers everybody should know” decreased from 1990–2020

#192

Earlier quoted context omitted.

Yeah, I was wondering where the heck 2ms disk seek times came from. That's not a thing and will never be a thing; disks only spin so fast, and nobody even uses >7200RPM drives any more (because we've all moved to SSDs instead).

Oh 7200 drives are used. Mainly for large data storage. If you deal with high quality videos (RAW 4K or 8K), SSDs are way too expensive to store them.

The parent comment said no one uses drives strictly faster than 7200.

Re: How “latency numbers everybody should know” decreased from 1990–2020

#193

Earlier quoted context omitted.

Yeah, I was wondering where the heck 2ms disk seek times came from. That's not a thing and will never be a thing; disks only spin so fast, and nobody even uses >7200RPM drives any more (because we've all moved to SSDs instead).

Oh 7200 drives are used. Mainly for large data storage. If you deal with high quality videos (RAW 4K or 8K), SSDs are way too expensive to store them.

GP was likely refering to extraordinary disks with more than 7200 rpm

Re: How “latency numbers everybody should know” decreased from 1990–2020

#194

Earlier quoted context omitted.

Yeah, I was wondering where the heck 2ms disk seek times came from. That's not a thing and will never be a thing; disks only spin so fast, and nobody even uses >7200RPM drives any more (because we've all moved to SSDs instead).

Oh 7200 drives are used. Mainly for large data storage. If you deal with high quality videos (RAW 4K or 8K), SSDs are way too expensive to store them.

[deleted]

Re: How “latency numbers everybody should know” decreased from 1990–2020

#195
post #21

Not an intuitive thing but the data is fascinating. A couple of notes of people who are confused by it: 1) The 'ns' next to the box is a graph legend not a data label (normally that would be in a box labeled legend to distinguish it from graph data) 2) The weird box and rectangle thing on the top is a slider, I didn't notice that until I was looking at the code and said "what slider?" 3) The only changes from 2005 to…

"And that means Amdahl's Law is more important than Moore's Law these days." idk, sure seems like we could have 1-2 cores (permanently pegged?) at 5 ghz for UI/UX then ($money / $costPerCores) number of cores for showing off/"performance" by now. But the OEMs haven't gone that way.

If you could have responsive and rich UI/UX 30-40 years ago you don't need anything but a highly efficient core prioritizing the UI. No need to waste energy on a super fast core.

Re: How “latency numbers everybody should know” decreased from 1990–2020

#196
post #174

Earlier quoted context omitted.

And Speed of light within Glass. We could still get that 1/3 back when we could somehow make ultra long distance hollow cable. We could get that Packet round trip from 150ms to 100ms. But I dont think hollow cable are anywhere close to commercial launch.

Starlink will get us there for at least long-distance connections once they have the laser inter-sat links fully connected.

At that level of optimization, the problem is not isolated. With Starlink the gain by using lasers is potentially lost with the additional processing that needs to happen when bouncing over multiple satellites.

Re: How “latency numbers everybody should know” decreased from 1990–2020

#197
I wish there was a version that normalized the times somehow instead of showing absolute times. Most of these numbers will get smaller simply because CPUs get faster, but it would be super helpful to get an accurate read whether the ratios of e.g. l1 to l2 to l3 to main memory lookup latencies changed significantly.

Re: How “latency numbers everybody should know” decreased from 1990–2020

#199

Earlier quoted context omitted.

Oh 7200 drives are used. Mainly for large data storage. If you deal with high quality videos (RAW 4K or 8K), SSDs are way too expensive to store them.

The parent comment said no one uses drives strictly faster than 7200.

Pretty sure 10K RPM drives are used too.

Re: How “latency numbers everybody should know” decreased from 1990–2020

#200

Earlier quoted context omitted.

The parent comment said no one uses drives strictly faster than 7200.

Pretty sure 10K RPM drives are used too.

I have no opinion on the matter, just pointing out that your comment doesn't follow from the previous one. But I imagine that when they said "nobody" uses faster disks, they were exaggerating a bit. The question is whether the default set of "latency numbers everyone should know" should reference SSDs or uncommon spinning disks.
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