I use an external PCIe cage (specifically the NA211TB) over a thunderbolt-2 cable. That gets me the 8xPCIe gen2 lanes to the GPU at full speed. I actually bought the cage for a different reason a few years back, so it was just sort of hanging around doing nothing...
Once Thunderbolt-3 comes around, it'll start to be a lot more common, I suspect. Never "mainstream" of course, but I can do real animation work on an older (quad-core i7) mac mini, with 3 displays, a 4TB SSD (again connected over TB2) and Blender or Poser to do the heavy lifting. There's a world of difference between using a GTX980Ti and the Intel 4000 graphics:)
I have a "Highpoint Thunderbolt-2 PCIe expansion station", or NA211TB. I got it on Amazon a couple of years back to put a Xilinx FPGA card into, it cost about $400. They've gone up a lot since then though. Last price I saw was ~$850... I'm not sure I would spend that much on an enclosure just for a GPU, but it was worth it for the FPGA card - that was a profitable project:)
The nice thing about the NA211TB is that it comes with a reasonably beefy (300W) PSU built in. There's no need for the ghetto wiring of a big-ass PC PSU into the guts of the PCIe cage to handle the large power requirements of a modern GPU. There's even space for another (single width) card in there...
There isn't a single Mac that is capable, no matter how much money you throw at Apple. Even if you could throw, say a Geforce GTX980ti in one, the drivers don't exist. Apple maintains complete driver control on their platform, and even when they DID provide options that included then-equivalent hardware, the performance was abysmal.
Chipset Model: NVIDIA GeForce GTX 980 Ti
Type: GPU
Bus: PCIe
PCIe Lane Width: x8
VRAM (Total): 6143 MB
Vendor: NVIDIA (0x10de)
Device ID: 0x17c8
Revision ID: 0x00a1
ROM Revision: VBIOS 84.00.36.00.90
Displays:
Cinema HD:
Display Type: LCD
Resolution: 2560 x 1600
Pixel Depth: 32-Bit Color (ARGB8888)
Display Serial Number: CY7350KMXMP
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Cinema HD Display:
Display Type: LCD
Resolution: 1200 x 1920
Pixel Depth: 32-Bit Color (ARGB8888)
Mirror: Off
Online: Yes
Rotation: 270
Cinema HD Display:
Display Type: LCD
Resolution: 1200 x 1920
Pixel Depth: 30-Bit Color (ARGB2101010)
Mirror: Off
Online: Yes
Rotation: 270
You were saying ?
Performance seems pretty darn good to me. This is a Mac mini, by the way. It's driving 2x23" monitors (sideways on, for coding on) and one 30" monitor (main display, in the c
I would point out though that Apple were one of the original investors in ARM. They even helped with the early (though not the initial) silicon design.
The article is also wrong on other points. I've had two companies in the UK, the first failed (and I didn't really feel any "stigma". It just didn't work out); the second (which contained mainly the same people as the first) was bought up, which is why I'm over in Sunny CA now rather than back in London...
The social net is actually a lot stronger in the UK I feel (as someone who's lived in the US for the last decade), so having a company fail on you isn't the enormous burden that it is in the USA. There's a lot of ways/government help to get back on your feet in the UK that still don't really exist in the USA; and, of course, there's things like government-sponsored healthcare so you don't *need* to be employed just to cover your arse on essential things like that.
If you're trying to imply that an iPad has as much malware "available" for it as a wintel tablet (which is basically just a pc), I have news for you, too.
OP here, way too late to matter, but still. It was poorly phrased. I missed the comma between high and six-figure. Where I come from, *any* 6-figure income would be considered high...
I'm one of said H1B visas, now with a green card. Been here almost exactly 10 years now, after Apple bought my company. I came here for the money and the weather, not for anything else. Frankly I don't think the US society is as "free" as people here seem to believe.
I've mentioned this here before, and (understandably, no-one likes bad news) I tend to get down voted for it, but the simple honest truth of the matter is that the USA isn't geared for looking after people, it's geared towards controlling people. There's things I like about it (the job is great, the weather is excellent, the people (as individuals who I meet day-to-day) are generally wonderful unless driving, the money is still good, I like my house and I met my wife here - my son is dual American/British).
There's things I don't like too, (the militarisation of the police, the lack of any reasonable healthcare, the "I'm alright Jack, screw you" attitude of a *lot* of people - weirdly enough those who often really *aren't* alright, the schooling system, and for lack of any better term, the country's soul). As time passes, and I get older, these seem to be more important. I can't see myself retiring here, and in fact I can't see myself here in another 10 years. That's not the attitude I came to the US with, it's something I've developed while I've been here.
Let's be frank here, I'm not trying to boast, but I'm one of the 'have's - I have a million dollar house (which sounds a lot more impressive than it really is in this neighbourhood) which is almost paid off, I have a high six-figure income, and I've money in the bank. I'm not a "1%er" but I'm up there with the rest... however, even with all of this, I'm not happy with the way the country is going. There's little-to-no safety net for joe public, and seemingly (*both* houses Republican, seriously ?) no desire for that. I think the USA is far closer to oligarchy than democracy, and the long-term trend just looks like it gets worse from here on out.
Nice to see breakthrough research like this coming from a single-payer healthcare system like the UK. When people start saying that the only places that can afford groundbreaking medical research are the ones where the "customers" pay a fortune, it'll be good to be able to point them to things like this.
As is the case a lot (not all) of the time with Apple. They're worth a lot in click-bait, so what you do is try to find something outrageous to say about a popular product, put adverts on the page to generate you cash, and try and profit from the massive public interest in yet another Apple product...
I live in CA too, and pay similar taxes. I don't have a problem with the taxes.
When I came to the USA, I was taken aback by just how money-orientated the churches are. I'm irreligious, but I attended church as a kid, and it was actually about the message, about community, and definitely not about the money. Church officials (rectors and curates) are pretty poor in the UK, at least where I grew up - they have housing provided for them, and they live on a meagre salary. They are expected to work long hours for low pay. I don't get that sense when I drive past a church in San Jose that has acres (literally) of parking space, flashy electronic signs, and is located in prime real-estate area. It's very different, trust me.
I've lived here in CA for almost a decade, as I said, it's been great. There's been a couple of local school-shootings in the last year or so. Understand that from a Brit's point of view *anyone* getting shot *ever* is big news. National, prime-time TV news, possibly for days. For it to be sufficiently commonplace that it doesn't even make it past local headlines is... disturbing.
Your point about talking to people is a good one: if I talk to people from outside the US, our views tend to resonate, but if I talk to people who are US-born, there's way less agreement. I'm not sure if it's because this is "normal" to those born here, that they just haven't experienced anything else, that they think somehow "it couldn't happen to me", or what (sometimes it's definitely a case of USA! USA! USA!). Definitely there is a difference in outlook between natives and foreigners.
One more thing: I'm not trying to paint the UK as some sort of panacea - it's not, by a long chalk. Neither am I US-bashing for the sake of it - the above is just my observations over time. The UK has it's own issues no doubt, but bottom line: even as a white male living in an affluent area in the USA, I feel safer in the UK. And I definitely feel my son would be safer at school there. This is the fact that's weighing on me more and more.
Having lived in the US for a decade now, I'm missing the UK more and more.
- A real non-half-assed health service, that provides long-term care without exception
- A dearth of mass-murders, especially school-shootings
- A police service which uses policing-by-consent rather than by-fear
- A university system that doesn't do its best to keep you in debt for life
- A foreign policy that doesn't make them hated around the world
- An attitude that doesn't revolve around "why should my taxes pay for you, just because you desperately need help" ?
- A church that isn't entirely based around making money for the "reverend" and isn't overwhelmingly politicised.
- Sensible views on evolution, science in general, abortion, gay marriage, and womens rights.
- And of course, the marked lack of guns in the general populace. An armed society is a polite society my arse. It's a *fearful* society.
As I said, I've been here for a decade now, and I work for a big company with great perks. It's been good for me, but now that I have a kid, the school-shootings thing is getting more and more worrisome. There's literally nothing I can do to prevent some moron raiding his mother's arsenal and killing my kid if that's how he wants to end his life.
The money is good, the people I meet are friendly, the weather is nice, and that used to be sufficient. But as time goes by, it's seeming more and more like a Faustian bargain.
Yeah, I could do with one of those office-space meme's right now.
If all the nay-sayers faux-gasping at the extreme length of 2.5m could shut up, that'd be great.
I'm not sure what people expect these days - this is a major achievement - whether it *can* be extended, or whether it *will* be extended would be different achievements. You could almost apply Jackson's rules of optimisation to this (refresher below) - in that first you *do* it, and only then (if you're an expert) do you try to do it *well*.
Simon
Jackson's rules of optimisation: "The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet."
I think you're proving my point about the black-and-white nature of how people regard free speech in the USA. See, I'm very much in favour of free speech, it's been a fundamental right of UK society now for longer than the USA has existed in its current form, and pretty much any UK citizen would be equally for it.
Where we differ is in nuance. The UK approach is a shades-of-gray one, where the right to speak whatever you want, no matter how hurtful to others, is actually counter-balanced by how much what you say hurts the target of your invective; and this in turn is counter-balanced by the importance of what it is that you're saying to society as a whole. There's a whole spectrum of things to consider when making a judgement, which is why the UK position is that if a free-speech issue comes up, it ought to be decided by a judge rather than a black/white hard-and-fast rule.
Now does this matter, in day-to-day life ? No. People say and do pretty much the same thing on both sides of the pond; but when a big issue comes up and a judgement has to be rendered, the courts take a more reasoned view than "Is this free speech ? Yes ? Ok then, feel free to ".
I'll ignore the idiotic purposeful misreading of the Fire thing...
In the UK, it's more of a "where is the harm" approach. If there is more perceived harm in the exercise of said speech than in allowing it, it won't be allowed. This is more difficult to administer (it means someone, usually a judge) has to make a decision about this rather than it just being black and white. It does make life more pleasant for more people.
Having lived in the UK and the US for over a decade each, I have some perspective on this, and personally I think it's worth it, worshipping at the altar of "Free Speech At All Costs[*]" is an absolute, and I tend to distrust absolutes.
Simon.
[*] It's not a real absolute in the USA, you can't shout "Fire!" in a crowded theatre in the US either, for example, but it's a massively more common mindset of US people compared to UK people in my experience.
Questioning and asking are two completely different things, otherwise one wouldn't "ask a question", one would either ask or question.
To question something is to doubt the premises that lead to a given statement. To ask something is to enquire about something. When one has doubts a conclusion (i.e.: questions), one normally asks to ascertain the veracity of the conclusion. This leads to the construct "to ask a question" as in "to resolve a doubt".
Yeah, but you need the lower level frames (link layer) to implement the higher level protocol (TCP) so that you can encapsulate another lower-level protocol within it; you can't implement TCP without any link-layer underneath it, is what I was trying to say. Note the "only" using TCP in the post.
What I'm really saying is that thunderbolt is like a transport layer protocol, and pci-e, Ethernet, video, etc. are all protocols layered on top of this transport protocol. It's very like the OSI stack, in as much as there's a link-level protocol and service-level protocols building on that basic transport.
I have no experience with PC motherboards so I'm not *sure* what they're doing, but I suspect that they are exposing any pci-e level protocol traffic as hot-plug pci-e (as does the Mac), and that the OP is misunderstanding what the author of the HTML page he linked to is saying.
Thunderbolt itself is a lower-level protocol, but one that can be addressed directly which can be useful for particular applications. One example is raw dma, so any thunderbolt device can dma into any other device without the CPU getting involved (modulo the conditions I mention above).
I thought the spec comment was a bit odd as well, but I think he might be referring to the fact that the spec (and the hardware) has changed over time. There are several revisions...
Dude, I'm just describing what I see. I have the docs too, for both protocol and controller chips, and I have the code and measurements to prove it.
There's a clear difference in the time taken to process packets once the kernel gets involved, and (within experimental error), that time difference is nicely quantized.
I can't say it any clearer, when the kernel doesn't need to get involved (see above for criteria), it just doesn't - at least on a Mac. Perhaps the bios's Greg is using are not implemented well, I don't know (I have no experience there) but the Mac does it intelligently.
I don't see how you can implement a lower-level protocol (eg: raw thunderbolt DMA) using a higher-level abstraction of that protocol (eg: pci-e traffic). That's like saying you'll implement Internet-layer frames only using TCP. Similarly, I don't see how you can expose something that doesn't conform to anything remotely like pci-e as a hot plug pci-e device - the latency tolerances to remain in spec are way different for a start.
I too have implemented a driver, from a high-end FPGA to the Mac, and the OSX kernel does not get involved unless you're traversing controllers within that Mac, or the route cannot be expressed within a single transaction, or if the destination is local. It just doesn't. These are to my knowledge the only 3 reasons for the local CPU to get involved:
[1] If you have a machine with devices (1,2,..) on multiple thunderbolt controllers (say A and B), it's possible to have a route like A2 -> A1-> A0 -/-> B0 -> B1, and of course the kernel is involved then because the individual controller chips A and B are not bridged together in any other way. The kernel has to route between A0 (local) and B0 (also local).
[2] The initial spec for thunderbolt allowed a lot of flexibility with source-defined routing tables, but it wasn't taken advantage of, and the later chips from Intel removed some of that functionality (or, more likely, just reassigned the chip real-estate to something more useful). There are now potentially valid routes that can't be expressed within a single frame, and the kernel has to be involved at that point as well, to make sure packets get to their correct destination. It is, however, unlikely that users will see these routing issues in real-world scenarios, you have to have a lot of devices on multiple busses before it's an issue.
[3] The destination is the local machine. Of course, the kernel has to get involved then.
I have a lot of diagnostic code that monitors bandwidth, packet lifetime and routing, and latencies. I've run massive stress tests on multiple machines and devices connected via thunderbolt, and so far, the above 3 reasons are the only ones that an OSX machine enters the kernel for any thunderbolt-related cause. It is quite clear when the kernel does get involved compared to when it doesn't, so I'm confident that if it doesn't have to get involved, there is no interaction.
Thunderbolt has only a passing acquaintance with pcie. It most certainly is not just a pcie bridge over wires rather than on board connectors. Thunderbolt is a switched packet network transport, and can route data packets of many types (including video, pcie, raw thunderbolt dma, etc.)
In addition, every thunderbolt port is a switch, using source-embedded routing to decide whether the packet ought to be forwarded n hops or whether it's destination is local - so the local CPU only gets involved if you're traversing thunderbolt controller chips, or if the packet is for the local machine.
There's a lot more to thunderbolt than just pcie, so if linux just treats it as pcie then linux is getting it wrong.
I'm not sure you got the point of the article - they were trying to match the specs of the capabilities in the Mac using commodity parts. The GPUs in the Mac Pro are the same as those firePro parts that cost a small fortune, and even a couple of R9 290x's wouldn't keep up because of a lack of VRAM (6GB of DDR5 vs 4GB on the 290's)
I'm not saying you need those gpu's, but if you're trying to match specs, those are the ones to choose. I think it's also clear that Apple are pushing gpu-based computing at the high end (they designed OpenCL after all), so high-load gpu code is likely to be common in the pro-apps. Those GPUs will be used on a mac.
Slashdot Mirror
I use an external PCIe cage (specifically the NA211TB) over a thunderbolt-2 cable. That gets me the 8xPCIe gen2 lanes to the GPU at full speed. I actually bought the cage for a different reason a few years back, so it was just sort of hanging around doing nothing...
Once Thunderbolt-3 comes around, it'll start to be a lot more common, I suspect. Never "mainstream" of course, but I can do real animation work on an older (quad-core i7) mac mini, with 3 displays, a 4TB SSD (again connected over TB2) and Blender or Poser to do the heavy lifting. There's a world of difference between using a GTX980Ti and the Intel 4000 graphics :)
Simon
I have a "Highpoint Thunderbolt-2 PCIe expansion station", or NA211TB. I got it on Amazon a couple of years back to put a Xilinx FPGA card into, it cost about $400. They've gone up a lot since then though. Last price I saw was ~$850... I'm not sure I would spend that much on an enclosure just for a GPU, but it was worth it for the FPGA card - that was a profitable project :)
The nice thing about the NA211TB is that it comes with a reasonably beefy (300W) PSU built in. There's no need for the ghetto wiring of a big-ass PC PSU into the guts of the PCIe cage to handle the large power requirements of a modern GPU. There's even space for another (single width) card in there...
There's a lot of info on techinferno.com - start at https://www.techinferno.com/in... :)
Simon
There isn't a single Mac that is capable, no matter how much money you throw at Apple. Even if you could throw, say a Geforce GTX980ti in one, the drivers don't exist. Apple maintains complete driver control on their platform, and even when they DID provide options that included then-equivalent hardware, the performance was abysmal.
[looks at computer. Yep, it still exists. Phew!]
simon% system_profiler SPDisplaysDataType
Graphics/Displays:
Intel HD Graphics 4000:
Chipset Model: Intel HD Graphics 4000
Type: GPU
Bus: Built-In
VRAM (Dynamic, Max): 1536 MB
Vendor: Intel (0x8086)
Device ID: 0x0166
Revision ID: 0x0009
NVIDIA GeForce GTX 980 Ti:
Chipset Model: NVIDIA GeForce GTX 980 Ti
Type: GPU
Bus: PCIe
PCIe Lane Width: x8
VRAM (Total): 6143 MB
Vendor: NVIDIA (0x10de)
Device ID: 0x17c8
Revision ID: 0x00a1
ROM Revision: VBIOS 84.00.36.00.90
Displays:
Cinema HD:
Display Type: LCD
Resolution: 2560 x 1600
Pixel Depth: 32-Bit Color (ARGB8888)
Display Serial Number: CY7350KMXMP
Main Display: Yes
Mirror: Off
Online: Yes
Rotation: Supported
Cinema HD Display:
Display Type: LCD
Resolution: 1200 x 1920
Pixel Depth: 32-Bit Color (ARGB8888)
Mirror: Off
Online: Yes
Rotation: 270
Cinema HD Display:
Display Type: LCD
Resolution: 1200 x 1920
Pixel Depth: 30-Bit Color (ARGB2101010)
Mirror: Off
Online: Yes
Rotation: 270
You were saying ?
Performance seems pretty darn good to me. This is a Mac mini, by the way. It's driving 2x23" monitors (sideways on, for coding on) and one 30" monitor (main display, in the c
I do. But then I work for Apple.
Apple pay the bills on my phone, but it's my phone.
Wish I had mod points.
I would point out though that Apple were one of the original investors in ARM. They even helped with the early (though not the initial) silicon design.
The article is also wrong on other points. I've had two companies in the UK, the first failed (and I didn't really feel any "stigma". It just didn't work out); the second (which contained mainly the same people as the first) was bought up, which is why I'm over in Sunny CA now rather than back in London...
The social net is actually a lot stronger in the UK I feel (as someone who's lived in the US for the last decade), so having a company fail on you isn't the enormous burden that it is in the USA. There's a lot of ways/government help to get back on your feet in the UK that still don't really exist in the USA; and, of course, there's things like government-sponsored healthcare so you don't *need* to be employed just to cover your arse on essential things like that.
Just my $0.02/£0.01 (rounding up)
Simon.
If you're trying to imply that an iPad has as much malware "available" for it as a wintel tablet (which is basically just a pc), I have news for you, too.
Fortunately the comment history is preserved. Not 5 posts up you state, and I quote:
"Most Americans don't understand just how restricted speech is in the UK by comparison to the US"
Restriction of free speech pertains to government restriction. We don't care what companies / institutions do. The BBC isn't the government.
So, I guess the gp was correct.
OP here, way too late to matter, but still. It was poorly phrased. I missed the comma between high and six-figure. Where I come from, *any* 6-figure income would be considered high...
Simon.
I'm one of said H1B visas, now with a green card. Been here almost exactly 10 years now, after Apple bought my company. I came here for the money and the weather, not for anything else. Frankly I don't think the US society is as "free" as people here seem to believe.
I've mentioned this here before, and (understandably, no-one likes bad news) I tend to get down voted for it, but the simple honest truth of the matter is that the USA isn't geared for looking after people, it's geared towards controlling people. There's things I like about it (the job is great, the weather is excellent, the people (as individuals who I meet day-to-day) are generally wonderful unless driving, the money is still good, I like my house and I met my wife here - my son is dual American/British).
There's things I don't like too, (the militarisation of the police, the lack of any reasonable healthcare, the "I'm alright Jack, screw you" attitude of a *lot* of people - weirdly enough those who often really *aren't* alright, the schooling system, and for lack of any better term, the country's soul). As time passes, and I get older, these seem to be more important. I can't see myself retiring here, and in fact I can't see myself here in another 10 years. That's not the attitude I came to the US with, it's something I've developed while I've been here.
Let's be frank here, I'm not trying to boast, but I'm one of the 'have's - I have a million dollar house (which sounds a lot more impressive than it really is in this neighbourhood) which is almost paid off, I have a high six-figure income, and I've money in the bank. I'm not a "1%er" but I'm up there with the rest... however, even with all of this, I'm not happy with the way the country is going. There's little-to-no safety net for joe public, and seemingly (*both* houses Republican, seriously ?) no desire for that. I think the USA is far closer to oligarchy than democracy, and the long-term trend just looks like it gets worse from here on out.
[sigh]
Simon.
Nice to see breakthrough research like this coming from a single-payer healthcare system like the UK. When people start saying that the only places that can afford groundbreaking medical research are the ones where the "customers" pay a fortune, it'll be good to be able to point them to things like this.
Simon
Well, since leaving college I've rarely used my Physics degree. He's just taking that to the logical conclusion...
As is the case a lot (not all) of the time with Apple. They're worth a lot in click-bait, so what you do is try to find something outrageous to say about a popular product, put adverts on the page to generate you cash, and try and profit from the massive public interest in yet another Apple product...
Or maybe I'm getting too cynical in my old age.
Simon
I live in CA too, and pay similar taxes. I don't have a problem with the taxes.
When I came to the USA, I was taken aback by just how money-orientated the churches are. I'm irreligious, but I attended church as a kid, and it was actually about the message, about community, and definitely not about the money. Church officials (rectors and curates) are pretty poor in the UK, at least where I grew up - they have housing provided for them, and they live on a meagre salary. They are expected to work long hours for low pay. I don't get that sense when I drive past a church in San Jose that has acres (literally) of parking space, flashy electronic signs, and is located in prime real-estate area. It's very different, trust me.
I've lived here in CA for almost a decade, as I said, it's been great. There's been a couple of local school-shootings in the last year or so. Understand that from a Brit's point of view *anyone* getting shot *ever* is big news. National, prime-time TV news, possibly for days. For it to be sufficiently commonplace that it doesn't even make it past local headlines is ... disturbing.
Your point about talking to people is a good one: if I talk to people from outside the US, our views tend to resonate, but if I talk to people who are US-born, there's way less agreement. I'm not sure if it's because this is "normal" to those born here, that they just haven't experienced anything else, that they think somehow "it couldn't happen to me", or what (sometimes it's definitely a case of USA! USA! USA!). Definitely there is a difference in outlook between natives and foreigners.
One more thing: I'm not trying to paint the UK as some sort of panacea - it's not, by a long chalk. Neither am I US-bashing for the sake of it - the above is just my observations over time. The UK has it's own issues no doubt, but bottom line: even as a white male living in an affluent area in the USA, I feel safer in the UK. And I definitely feel my son would be safer at school there. This is the fact that's weighing on me more and more.
Simon
Having lived in the US for a decade now, I'm missing the UK more and more.
- A real non-half-assed health service, that provides long-term care without exception
- A dearth of mass-murders, especially school-shootings
- A police service which uses policing-by-consent rather than by-fear
- A university system that doesn't do its best to keep you in debt for life
- A foreign policy that doesn't make them hated around the world
- An attitude that doesn't revolve around "why should my taxes pay for you, just because you desperately need help" ?
- A church that isn't entirely based around making money for the "reverend" and isn't overwhelmingly politicised.
- Sensible views on evolution, science in general, abortion, gay marriage, and womens rights.
- And of course, the marked lack of guns in the general populace. An armed society is a polite society my arse. It's a *fearful* society.
As I said, I've been here for a decade now, and I work for a big company with great perks. It's been good for me, but now that I have a kid, the school-shootings thing is getting more and more worrisome. There's literally nothing I can do to prevent some moron raiding his mother's arsenal and killing my kid if that's how he wants to end his life.
The money is good, the people I meet are friendly, the weather is nice, and that used to be sufficient. But as time goes by, it's seeming more and more like a Faustian bargain.
Simon.
Yeah, I could do with one of those office-space meme's right now.
If all the nay-sayers faux-gasping at the extreme length of 2.5m could shut up, that'd be great.
I'm not sure what people expect these days - this is a major achievement - whether it *can* be extended, or whether it *will* be extended would be different achievements. You could almost apply Jackson's rules of optimisation to this (refresher below) - in that first you *do* it, and only then (if you're an expert) do you try to do it *well*.
Simon
Jackson's rules of optimisation: "The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet."
[sigh]
*gives up trying to reason. There's none so blind as those who don't want to see...
I think you're proving my point about the black-and-white nature of how people regard free speech in the USA. See, I'm very much in favour of free speech, it's been a fundamental right of UK society now for longer than the USA has existed in its current form, and pretty much any UK citizen would be equally for it.
Where we differ is in nuance. The UK approach is a shades-of-gray one, where the right to speak whatever you want, no matter how hurtful to others, is actually counter-balanced by how much what you say hurts the target of your invective; and this in turn is counter-balanced by the importance of what it is that you're saying to society as a whole. There's a whole spectrum of things to consider when making a judgement, which is why the UK position is that if a free-speech issue comes up, it ought to be decided by a judge rather than a black/white hard-and-fast rule.
Now does this matter, in day-to-day life ? No. People say and do pretty much the same thing on both sides of the pond; but when a big issue comes up and a judgement has to be rendered, the courts take a more reasoned view than "Is this free speech ? Yes ? Ok then, feel free to ".
I'll ignore the idiotic purposeful misreading of the Fire thing...
This is a very US-typical way of thinking.
In the UK, it's more of a "where is the harm" approach. If there is more perceived harm in the exercise of said speech than in allowing it, it won't be allowed. This is more difficult to administer (it means someone, usually a judge) has to make a decision about this rather than it just being black and white. It does make life more pleasant for more people.
Having lived in the UK and the US for over a decade each, I have some perspective on this, and personally I think it's worth it, worshipping at the altar of "Free Speech At All Costs[*]" is an absolute, and I tend to distrust absolutes.
Simon.
[*] It's not a real absolute in the USA, you can't shout "Fire!" in a crowded theatre in the US either, for example, but it's a massively more common mindset of US people compared to UK people in my experience.
Questioning and asking are two completely different things, otherwise one wouldn't "ask a question", one would either ask or question.
To question something is to doubt the premises that lead to a given statement. To ask something is to enquire about something. When one has doubts a conclusion (i.e.: questions), one normally asks to ascertain the veracity of the conclusion. This leads to the construct "to ask a question" as in "to resolve a doubt".
Simon
Yeah, but you need the lower level frames (link layer) to implement the higher level protocol (TCP) so that you can encapsulate another lower-level protocol within it; you can't implement TCP without any link-layer underneath it, is what I was trying to say. Note the "only" using TCP in the post.
What I'm really saying is that thunderbolt is like a transport layer protocol, and pci-e, Ethernet, video, etc. are all protocols layered on top of this transport protocol. It's very like the OSI stack, in as much as there's a link-level protocol and service-level protocols building on that basic transport.
I have no experience with PC motherboards so I'm not *sure* what they're doing, but I suspect that they are exposing any pci-e level protocol traffic as hot-plug pci-e (as does the Mac), and that the OP is misunderstanding what the author of the HTML page he linked to is saying.
Thunderbolt itself is a lower-level protocol, but one that can be addressed directly which can be useful for particular applications. One example is raw dma, so any thunderbolt device can dma into any other device without the CPU getting involved (modulo the conditions I mention above).
I thought the spec comment was a bit odd as well, but I think he might be referring to the fact that the spec (and the hardware) has changed over time. There are several revisions...
Dude, I'm just describing what I see. I have the docs too, for both protocol and controller chips, and I have the code and measurements to prove it.
There's a clear difference in the time taken to process packets once the kernel gets involved, and (within experimental error), that time difference is nicely quantized.
I can't say it any clearer, when the kernel doesn't need to get involved (see above for criteria), it just doesn't - at least on a Mac. Perhaps the bios's Greg is using are not implemented well, I don't know (I have no experience there) but the Mac does it intelligently.
I don't see how you can implement a lower-level protocol (eg: raw thunderbolt DMA) using a higher-level abstraction of that protocol (eg: pci-e traffic). That's like saying you'll implement Internet-layer frames only using TCP. Similarly, I don't see how you can expose something that doesn't conform to anything remotely like pci-e as a hot plug pci-e device - the latency tolerances to remain in spec are way different for a start.
I too have implemented a driver, from a high-end FPGA to the Mac, and the OSX kernel does not get involved unless you're traversing controllers within that Mac, or the route cannot be expressed within a single transaction, or if the destination is local. It just doesn't. These are to my knowledge the only 3 reasons for the local CPU to get involved:
[1] If you have a machine with devices (1,2,..) on multiple thunderbolt controllers (say A and B), it's possible to have a route like A2 -> A1-> A0 -/-> B0 -> B1, and of course the kernel is involved then because the individual controller chips A and B are not bridged together in any other way. The kernel has to route between A0 (local) and B0 (also local).
[2] The initial spec for thunderbolt allowed a lot of flexibility with source-defined routing tables, but it wasn't taken advantage of, and the later chips from Intel removed some of that functionality (or, more likely, just reassigned the chip real-estate to something more useful). There are now potentially valid routes that can't be expressed within a single frame, and the kernel has to be involved at that point as well, to make sure packets get to their correct destination. It is, however, unlikely that users will see these routing issues in real-world scenarios, you have to have a lot of devices on multiple busses before it's an issue.
[3] The destination is the local machine. Of course, the kernel has to get involved then.
I have a lot of diagnostic code that monitors bandwidth, packet lifetime and routing, and latencies. I've run massive stress tests on multiple machines and devices connected via thunderbolt, and so far, the above 3 reasons are the only ones that an OSX machine enters the kernel for any thunderbolt-related cause. It is quite clear when the kernel does get involved compared to when it doesn't, so I'm confident that if it doesn't have to get involved, there is no interaction.
Thunderbolt has only a passing acquaintance with pcie. It most certainly is not just a pcie bridge over wires rather than on board connectors. Thunderbolt is a switched packet network transport, and can route data packets of many types (including video, pcie, raw thunderbolt dma, etc.)
In addition, every thunderbolt port is a switch, using source-embedded routing to decide whether the packet ought to be forwarded n hops or whether it's destination is local - so the local CPU only gets involved if you're traversing thunderbolt controller chips, or if the packet is for the local machine.
There's a lot more to thunderbolt than just pcie, so if linux just treats it as pcie then linux is getting it wrong.
I'm not sure you got the point of the article - they were trying to match the specs of the capabilities in the Mac using commodity parts. The GPUs in the Mac Pro are the same as those firePro parts that cost a small fortune, and even a couple of R9 290x's wouldn't keep up because of a lack of VRAM (6GB of DDR5 vs 4GB on the 290's)
I'm not saying you need those gpu's, but if you're trying to match specs, those are the ones to choose. I think it's also clear that Apple are pushing gpu-based computing at the high end (they designed OpenCL after all), so high-load gpu code is likely to be common in the pro-apps. Those GPUs will be used on a mac.