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Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

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Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#101

Post by IshKebab »

rurban wrote: post #80
rui314 wrote: post #10

Earlier quoted context omitted.

If it takes 20 seconds, you go for a coffee or switch the window to start web browsing, but if it takes only 2 seconds, you can wait without being distracted. So it's more than just saving 18 seconds for each build. It wouldn't interrupt your flow.

our builds usually take 1-4 hours on windows with crazy conan. even cached binaries don't help much. a simple rebase could last 2 days.

Jesus. What product? The only thing I've ever worked on that got close to that was a compiler that built LLVM and Boost. LLVM takes like 40 minutes on a laptop.

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#102

Post by wyldfire »

rui314 wrote: post #14
wyldfire wrote: post #11

Earlier quoted context omitted.

Rui has made it explicit that a commercial license is available. Hey Rui, you should replace "please call" with a dollar amount in order to increase your conversion rate ;)

I dislike "contact us for pricing" too, but pricing is hard! I don't know how much I should ask for. This is also a bit unusual business model because mold can be used for free. I'm happy if users pay me 10%-20% of the total cost they could save by using mold though.

I was joking and I don't think you need a price on there. But if you're serious, you can put out an asking price and everyone involved should just assume it's negotiable. Just use something like a couple of million USD as a starting point.

> This is also a bit unusual business model because mold can be used for free.

You're selling the copyright, right? That's ok - businesses pay for stuff like this. Although I wonder if instead you'd be better off if you created a corporation and instead offered to sell the company's IP + your commitment to support the work over ~1-2 years. This might be a more common scenario for M&A teams to work with. Especially if you are keen on supporting more target architectures/OSs. Someone like ARM or SiFive or FAANG would easily shell out that kind of money to get mold.

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#103

Post by IshKebab »

5e92cb50239222b wrote: post #50
1f60c wrote: post #47

Earlier quoted context omitted.

> $200K is nowadays an annual total compensation of a junior dev *in the US. In my country, those salaries are completely unheard of.

In my country, $200k is what a senior dev makes in 10 years. The issue is, I very much doubt people like Rui could be expected to live in places like mine. So comparing against US salaries is probably what you should do anyway.

I'm curious - is that salary difference enough to cause a significant brain drain? Can you hire really good developers for that price in your country?

I live in the UK and dev salaries are maybe half of the US, but people don't leave in droves because there are other factors - family, friends, quality of life, effort of moving your life across continents, etc.

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#104

Post by saghm »

rui314 wrote: post #14
wyldfire wrote: post #11

Earlier quoted context omitted.

Rui has made it explicit that a commercial license is available. Hey Rui, you should replace "please call" with a dollar amount in order to increase your conversion rate ;)

I dislike "contact us for pricing" too, but pricing is hard! I don't know how much I should ask for. This is also a bit unusual business model because mold can be used for free. I'm happy if users pay me 10%-20% of the total cost they could save by using mold though.

Build times are a huge issue impacting how fast I can develop at my job (and I'm fairly certain that's the norm for my team), and I suspect that using a faster linker would mitigate that by a significant chunk. Unfortunately I'm just an IC and don't have the authority to look into something like paying for this, and I'd likely need to actually try it out and show numbers for how much things would improve to get management interested in actually looking into this. Because the project I work on requires interfacing with some cloud services that I can't connect to locally, I would either need to actually build on one of our cloud servers or compile the entire thing locally and copy it over, but I imagine the performance gains from multithreading would not be nearly as great on the 8 cores on my laptop compared to the 64 on my cloud server. I'm a bit hesitant to take initiative and just try this out due to the AGPL license though, since IANAL and I imagine if I tried to get permission for this internally, I'd run into the circular issue that without data to show it's worth it to look into, I'd probably just be told not to do it.

Basically, I think your best chance of generating interest from this is the bottom-up (since the individual engineers are the ones who would be feeling the pain that this could help solve), but I'm not really sure ICs at the companies large enough to be potential customers for this have any likely path forward with the way you've structured things right now. I'm not sure if you're flexible on this at all, and obviously I can't guarantee we'd get anywhere, but if you're interested in hearing more details about the potential use my team (and probably a number of other teams at my company would be able to make use if we were able to work something out), feel free to email me! Any prefix @.com will forward to my gmail.

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#105

Post by maccard »

jeffbee wrote: post #95
dxf wrote: post #88

Earlier quoted context omitted.

Linkers can also do something called "Identical code folding", or ICF, whereby the linker notices that two pieces of code are exactly the same and can merge them. lld's sources include a little overview of how this is done, see https://github.com/llvm-mirror/lld/blob/master/ELF/ICF.cpp

ICF exists but no linker is going to silently do it behind your back without an explicit directive, because it breaks debugging in certain ways. Folded identical functions can't be disambiguated in the file/line tables, so symbolized backtraces may contain impossible calls.

> CF exists but no linker is going to silently do it behind your back without an explicit directive,

Those explicit directives might be more implicit than you think. A linker will likely fold functions declared as inline. Template functions and template classes are implicitly inline, so for example, all uses of std::vector will (likely) be implicitly folded together.

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#106

Post by amelius »

maccard wrote: post #105
jeffbee wrote: post #95

Earlier quoted context omitted.

ICF exists but no linker is going to silently do it behind your back without an explicit directive, because it breaks debugging in certain ways. Folded identical functions can't be disambiguated in the file/line tables, so symbolized backtraces may contain impossible calls.

> CF exists but no linker is going to silently do it behind your back without an explicit directive, Those explicit directives might be more implicit than you think. A linker will likely fold functions declared as inline. Template functions and template classes are implicitly inline, so for example, all uses of std::vector will (likely) be implicitly folded together.

Aren't these folded by the compiler already?

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#107

Post by maccard »

amelius wrote: post #106
maccard wrote: post #105

Earlier quoted context omitted.

> CF exists but no linker is going to silently do it behind your back without an explicit directive, Those explicit directives might be more implicit than you think. A linker will likely fold functions declared as inline. Template functions and template classes are implicitly inline, so for example, all uses of std::vector will (likely) be implicitly folded together.

Aren't these folded by the compiler already?

Not if they're compiled by separate invocations of the compiler. If a.cpp and b.cpp both have a vector and are compiled independently, the first tool that actually gets to see them both is likely a linker (or archiver but that's a glorified zip tool)

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#108

Post by amelius »

maccard wrote: post #107
amelius wrote: post #106

Earlier quoted context omitted.

Aren't these folded by the compiler already?

Not if they're compiled by separate invocations of the compiler. If a.cpp and b.cpp both have a vector and are compiled independently, the first tool that actually gets to see them both is likely a linker (or archiver but that's a glorified zip tool)

Ok, but if these functions are inlined, would a linker then be able to fold these definitions?

(Or are you assuming that a debug flag is used so that all inlined functions are not really inlined by the compiler?)

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#109

Post by jeffbee »

maccard wrote: post #107
amelius wrote: post #106

Earlier quoted context omitted.

Aren't these folded by the compiler already?

Not if they're compiled by separate invocations of the compiler. If a.cpp and b.cpp both have a vector and are compiled independently, the first tool that actually gets to see them both is likely a linker (or archiver but that's a glorified zip tool)

OK but removing functions that are identical and that have the same name is not "identical code folding". ICF is removing functions that have identical bodies and different names.

Re: Mold/macOS is 11 times faster than the Apple's default linker to link Chrome

#110

Post by dang »

guessbest wrote: post #93
astrostl wrote: post #91

I can infer from context that mold is a linker. It took searching for https://github.com/rui314/mold to learn what it actually was, though: "mold is a faster drop-in replacement for existing Unix linkers. It is several times faster than the LLVM lld linker, the second-fastest open-source linker which I originally created a few years ago. mold is designed to increase developer productivity by reducing build time, espe…

I think yn is a mature enough site that stories are placed by the site curators and twitter users with connections to the site moderators are part of the curation process. There have been a lot more twitter posts as new submissions this past year or two. Also, thank you for finding out what the topic discussion was about and sharing. I couldn't infer the meaning.

Some posts get picked for a second-chance by moderators - see https://news.ycombinator.com/item?id=26998308 - but it doesn't have any connection to twitterers, nor to 'connections to the site moderators', except in the sense that we recognize some usernames as good submitters.

The intention is just to comb through the stacks looking for good stories that didn't get attention the first time around—especially on topics that aren't correlated with anything else. HN has a wealth of these and I'm pretty sure we still miss half of them.

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