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Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

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Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#61

Post by trhway »

Retric wrote: post #51
winkeltripel wrote: post #28

Earlier quoted context omitted.

If spending hours a day at 100% utility, SSDs will rarely last 5 years.

If your SSD would be at 100% utilization it’s going to take a lot of HDD to reach that kind of bandwidth. To the point where for high bandwidth loads SSD’s actually cost less even if you have to replace them regularly. 100% utilization and 30x the bandwidth = 30x as many HDD. Alternatively, if HDD’s are an option you’re a long way from 100% utilization.

SSD have hard time sustaining 200-400Mb/s write where is 4 HDD do is easily. Our case isn't that much about IOPS.

Anyway, reasonably available SSDs have up to [1000 x SSD size] total write limit, so doing couple of 400G builds/day would use up the 1TB drive in 3 years. At worst times we had to develop&maintain 5 releases in parallel instead of regular 2-3.

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#62

Post by pdimitar »

mywittyname wrote: post #52
kyrra wrote: post #34

Earlier quoted context omitted.

Depends on the kind of SSD. If it's using SLC, the write endurance is much much higher. If you're going with cheap SSDs (TLC or QLC), your write endurance will suck. see: https://www.anandtech.com/show/6459/samsung-ssd-840-testing-...

SLC seems to be going away pretty quickly, if it hasn't already been phased out. It just can't produce the price / GB of the better tech. Also, that article you linked is almost 10 years old. You're best bet for long-term reliability is to buy much more capacity than you need and try not to exceed >50% capacity for high write frequency situations. I keep an empty drive around to use as a temp directory for compiling,…

I recently bought an external 32GB SLC SSD (in the form factor of an USB pendrive). Its random read/write speeds are quite insane (130+ MB/s both) while consumer SSDs like the Samsung 850 Evo barely manage 30 MB/s read/write. It's also advertised as very durable.

I plan on using a couple of those as ZFS metadata and small block caches for my home NAS, we'll see how it goes but people generally and universally praise the SLC SSDs for their durability.

> You're best bet for long-term reliability is to buy much more capacity than you need and try not to exceed >50% capacity for high write frequency situations. I keep an empty drive around to use as a temp directory for compiling, logging, temp files, etc.

That's likely true. I am pondering buying one external NVMe SSD for that purpose exactly.

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#64

Post by frizkie »

fctorial wrote: post #53
ska wrote: post #18

Earlier quoted context omitted.

I suspect the biggest (build time) benefit to most c++ workflows and toolchains was the move to ubiquitous SSD. Prior to that in my experience excepting expensive RAID array dedicated build machines, it was really easy to build a system that would always be IO bound on builds. There of course were tricks to improve things but you still tended to hit that wall unless your CPUs were really under spec. edit: to be clear…

Don't SSDs have a finite TBW? 50GB of writes everyday (possible on large projects) will consume that in a couple of months.

They do but it's really large. The Tech Report did an endurance test on SSDs 5-6 years ago [0]. The tests took 18 months before all 6 SSDs were dead.

Generally you're looking at hundreds of terabytes, if not more than a petabyte in total write capacity before the drive is unusable.

This is for older drives (~6 years old as I said), and I don't know enough about storage technology and where it's come since then to say, but I imagine things probably have not gotten worse.

[0]: https://techreport.com/review/27909/the-ssd-endurance-experi...

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#65

Post by bmurphy1976 »

PragmaticPulp wrote: post #13

Fun experiment. The more pedestrian 5950X or the now bargain 3950X are great for anyone doing a lot of compiling. With the right motherboard they even have ECC RAM support. Game changer for workstations in the $1000–$2000 range. The more expensive Threadripper parts really shine when memory bandwidth becomes a bottleneck. In my experience, compiling code hasn’t been very memory bandwidth limited. However, some of my…

Where can you get decent ECC ram for a reasonable price? I was on the hunt recently for ECC RAM for my new desktop and I gave up and pulled the trigger on low latency non-ECC RAM. Availability seems to be pretty terrible at the moment.

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#66

Post by d00bianista »

mywittyname wrote: post #52
kyrra wrote: post #34

Earlier quoted context omitted.

Depends on the kind of SSD. If it's using SLC, the write endurance is much much higher. If you're going with cheap SSDs (TLC or QLC), your write endurance will suck. see: https://www.anandtech.com/show/6459/samsung-ssd-840-testing-...

SLC seems to be going away pretty quickly, if it hasn't already been phased out. It just can't produce the price / GB of the better tech. Also, that article you linked is almost 10 years old. You're best bet for long-term reliability is to buy much more capacity than you need and try not to exceed >50% capacity for high write frequency situations. I keep an empty drive around to use as a temp directory for compiling,…

It's actually not better tech, instead it's more complicated, more error prone and less durable ways to use the same technology that produces more space for a lower price. MLC is pretty much okay but TLC is a little too fragile and low performance in my opinion. I prefer spinning HDD's over QLC since the spinning drives have predictable performance.

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#67

Post by ahepp »

bullen wrote: post #47
jcelerier wrote: post #43

Earlier quoted context omitted.

You just need more ram. I 'ever compile at less than -j$(ncpu). Hard with less than 32 GB tho - a single clang instance can easily eat upwards of 1gb of ram

Aha, I only compile on ARM so I got no room to increase RAM... Is it the same with g++? I have 4GB so I should be able to compile with 4 cores, but the processes only fill 2-3 cores even when I try make -j8 on a 8 core machine and then locks the entire OS until it craps out?! Something is fishy...

Why are you compiling on ARM with only 4GB RAM? Wouldn't it make more sense to cross compile from a machine with more resources, if you cared about build speed? (maybe there's a good reason not to do that, idk)

If it's crapping out when you give it -j8, that seems to strongly suggest you're running into limited resources somewhere.

I'm no expert in the intricacies of parallel builds, but as far as I know you can still have dependencies between targets that will limit parallelism.

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#68

Post by masklinn »

PragmaticPulp wrote: post #13

Fun experiment. The more pedestrian 5950X or the now bargain 3950X are great for anyone doing a lot of compiling. With the right motherboard they even have ECC RAM support. Game changer for workstations in the $1000–$2000 range. The more expensive Threadripper parts really shine when memory bandwidth becomes a bottleneck. In my experience, compiling code hasn’t been very memory bandwidth limited. However, some of my…

> The more expensive Threadripper parts really shine when memory bandwidth becomes a bottleneck.

Threadripper can be useful for IO, especially for C++ (which is famously quite IO intensive) owing to its 128 PCIe lanes, you can RAID0 a bunch of drives and have absolutely ridiculous IO.

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#69

Post by [deleted] »

trhway wrote: post #61
Retric wrote: post #51

Earlier quoted context omitted.

If your SSD would be at 100% utilization it’s going to take a lot of HDD to reach that kind of bandwidth. To the point where for high bandwidth loads SSD’s actually cost less even if you have to replace them regularly. 100% utilization and 30x the bandwidth = 30x as many HDD. Alternatively, if HDD’s are an option you’re a long way from 100% utilization.

SSD have hard time sustaining 200-400Mb/s write where is 4 HDD do is easily. Our case isn't that much about IOPS. Anyway, reasonably available SSDs have up to [1000 x SSD size] total write limit, so doing couple of 400G builds/day would use up the 1TB drive in 3 years. At worst times we had to develop&maintain 5 releases in parallel instead of regular 2-3.

[deleted]

Re: Threadripper 3990X: The Quest To Compile 1B Lines Of C++ On 64 Cores

#70

Post by m463 »

bmurphy1976 wrote: post #65
PragmaticPulp wrote: post #13

Fun experiment. The more pedestrian 5950X or the now bargain 3950X are great for anyone doing a lot of compiling. With the right motherboard they even have ECC RAM support. Game changer for workstations in the $1000–$2000 range. The more expensive Threadripper parts really shine when memory bandwidth becomes a bottleneck. In my experience, compiling code hasn’t been very memory bandwidth limited. However, some of my…

Where can you get decent ECC ram for a reasonable price? I was on the hunt recently for ECC RAM for my new desktop and I gave up and pulled the trigger on low latency non-ECC RAM. Availability seems to be pretty terrible at the moment.

same for everything. 5950? where would you even get one?

wait - seems you can get one, just pay 2x list price.

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