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> Maybe I've just got unlucky in the past, but in most projects I worked on a lot of developer time was wasted on waiting for PRs to go green. I don't understa

• mark_undoio 1y ago
  > I don't understand this. Developer time is so much more expensive than machine time. Do companies not just double their CI workers after hearing people complain? It's just a throw-more-resources problem. I'd personally agree. But this sounds like the kind of thing that, at many companies, could be a real challenge. Ultimately, you can measure dollars spent on CI workers. It's much harder and less direct to quantify the cost of not having them (until, for instance, people start taking shortcuts with testing and a regression escapes to production). That kind of asymmetry tends, unless somebody has a strong overriding vision of where the value really comes from, to result in penny pinching on the wrong things.
  • mike_hearn 1y ago
    It's more than that. You can measure salaries too, measurement isn't the issue. The problem is that if you let people spend the companies money without any checks or balances they'll just blow through unlimited amounts of it. That's why companies always have lots of procedures and policies around expense reporting. There's no upper limit to how much money developers will spend on cloud hardware given the chance, as the example above of casually running a test 10,000 times in parallel demonstrates nicely. CI doesn't require you to fill out an expense report every time you run a PR thank goodness, but there still has to be a way to limit financial liability. Usually companies do start out by doubling cluster sizes a few times, but each time it buys a few months and then the complaints return. After a few rounds of this managers realize that demand is unlimited and start pushing back on always increasing the budget. Devs get annoyed and spend an afternoon on optimizations, suddenly times are good again. The meme on HN is that developer time is always more expensive than machine time, but I've been on both sides of this and seen how the budgets work out. It's often not true, especially if you use clouds like Azure which are overloaded and expensive, or have plenty of junior devs, and/or teams outside the US where salaries are lower. There's often a lot of low hanging fruit in test times so it can make sense to optimize, even so, huge waste is still the order of the day.
• mike_hearn 1y ago
  I was also at Google for years. Places like that are not even close to representative. They can afford to just-throw-more-resources, they get bulk discounts on hardware and they pay top dollar for engineers. In more common scenarios that represent 95% of the software industry CI budgets are fixed, clusters are sized to be busy most of the time, and you cannot simply launch 10,000 copies of the same test on 10,000 machines. And even despite that these CI clusters can easily burn through the equivalent of several SWE salaries. > These are orthogonal. You want maximum deterministic CI steps so that you make builds fully hermetic and cache every single thing. Again, that's how companies like Google do it. In normal companies, build caching isn't always perfectly reliable, and if CI runs suffer flakes due to caching then eventually some engineer is gonna get mad and convince someone else to turn the caching off. Blaze goes to extreme lengths to ensure this doesn't happen, and Google spends extreme sums of money on helping it do that (e.g. porting third party libraries to use Blaze instead of their own build system). In companies without money printing machines, they sacrifice caching to get determinism and everything ends up slow.
  • PaulHoule 1y ago
    Most of my experience writing concurrent/parallel code in (mainly) Java has been rewriting half-baked stuff that would need a lot of testing with straightforward reliable and reasonably performant code that uses sound and easy-to-use primitives such as Executors (watch out for teardown though), database transactions, atomic database operations, etc. Drink the Kool Aid and mess around with synchronized or actors or Streams or something and you're looking at a world of hurt. I've written a limited number of systems that needed tests that probe for race conditions by doing something like having 3000 threads run a random workload for 40 seconds. I'm proud of that "SuperHammer" test on a certain level but boy did I hate having to run it with every build.
    • switchbak 1y ago
      I’m all for n boring tech and all, and leveraging the simplest thing that can work. But arguing against streams? You mean reactive streams? These have helped me replace megabytes of poorly written concurrent/parallel crap with a few lines of stream orchestration. I find it interesting that our experiences diverge so wildly. Then again, I’ve had to rewrite some terribly clever code, some downright diabolical, so that could be part of it.
• mystified5016 1y ago
  IME it's less of a "throw more resources" problem and more of a "stop using resources in literally the worst way possible" CI caching is, apparently, extremely difficult. Why spend a couple of hours learning about your CI caches when you can just download and build the same pinned static library a billion times? The server you're downloading from is (of course) someone else's problem and you don't care about wasting their resources either. The power you're burning by running CI for there hours instead of one is also someone else's problem. Compute time? Someone else's problem. Cloud costs? You bet it's someone else's problem. Sure, some things you don't want to cache. I always do a 100% clean build when cutting a release or merging to master. But for intermediate commits on a feature branch? Literally no reason not to cache builds the exact same way you do on your local machine.
• ronbenton 1y ago
  >Do companies not just double their CI workers after hearing people complain? They do not. I don't know if it's a matter of justifying management levels, but these discussions are often drawn out and belabored in my experience. By the time you get approval, or even worse, rejected, for asking for more compute (or whatever the ask is), you've spent way more money on the human resource time than you would ever spend on the requested resources.
  • kccqzy 1y ago
    I have never once been refused by a manager or director when I am explicitly asking for cost approval. The only kind of long and drawn out discussions are unproductive technical decision making. Example: the ask of "let's spend an extra $50,000 worth of compute on CI" is quickly approved but "let's locate the newly approved CI resource to a different data center so that we have CI in multiple DCs" solicits debates that can last weeks.
  • mysteria 1y ago
    This is exactly my experience with asking for more compute at work. We have to prepare loads of written justification, come up with alternatives or optimizations (which we already know won't work), etc. and in the end we choose the slow compute and reduced productivity over the bureaucracy. And when we manage to make a proper request it ends up being rejected anyways as many other teams are asking for the same thing and "the company has limited resources". Duh.
• IshKebab 1y ago
  Developer time is more expensive than machine time, but at most companies it isn't 10000x more expensive. Google is likely an exception because it pays extremely well and has access to very cheap machines. Even then, there are other factors: * You might need commercial licenses. It may be very cheap to run open source code 10000x, but guess how much 10000 Questa licenses cost. * Moores law is dead Amdahl's law very much isn't. Not everything is embarrassingly parallel. * Some people care about the environment. I worked at a company that spent 200 CPU hours on every single PR (even to fix typos; I failed to convince them they were insane for not using Bazel or similar). That's a not insignificant amount of CO2.
  • underdeserver 1y ago
    That's solvable with modern cloud offerings - Provision spot instances for a few minutes and shut them down afterwards. Let the cloud provider deal with demand balancing. I think the real issue is that developers waiting for PRs to go green are taking a coffee break between tasks, not sitting idly getting annoyed. If that's the case you're cutting into rest time and won't get much value out of optimizing this.
    • IshKebab 1y ago
      Both companies I've worked in recently have been too paranoid about IP to use the cloud for CI. Anyway I don't see how that solves any of the issues except maybe cost to some degree (but maybe not; cloud is expensive).
      • fragmede 1y ago
        Sorta. For CI/CD you can use spot instances and spin them down outside of business hours, so they can end up being cheaper than buying many really beefy machines and amortizing them over the standard depreciation schedule.
        • IshKebab 1y ago
          Yeah though not for silicon verification because we always run more tests overnight. They get basically 100% utilisation.
• physicsguy 1y ago
  Not really, in most small companies/departments, £100k a month is considered a painful cloud bill and adding more EC2 instances to provide cloud runners can add 10% to that easily.
• wat10000 1y ago
  Many companies are strangely reluctant to spend money on hardware for developers. They might refuse to spend $1,000 on a better laptop to be used for the next three years by an employee, whose time costs them that much money in a single afternoon.
  • kridsdale1 1y ago
    I have faced this at each of the $50B in profit companies I have worked at.
    • duderific 1y ago
      Well how do you think they got to $50B profit? /s
  • PaulHoule 1y ago
    That's been a pet peeve of mine for so long. (Glad my current employer gets me the best 1.5ℓ machine from Dell every few years!) On the other hand I've seen many overcapitalized pre-launch startups go for months with a $20,000+ AWS bill without thinking about it then suddenly panic about what they're spending; they'd find tens of XXXXL instances spun up doing nothing, S3 buckets full of hundreds of terabytes of temp files that never got cleared out, etc. With basic due diligence they could have gotten that down to $2k a month, somebody obsessive about cost control could have done even better.
• wbl 1y ago
  No it is not. Senior management often has a barely disguised contempt for engineering and spending money to do a better job. They listen much more to sales complain.
  • kridsdale1 1y ago
    That depends on the company.
• MangoToupe 1y ago
  Writing testing infrastructure so that you can just double workers and get a corresponding doubling in productivity is non-trivial. Certainly I've never seen anything like Google's testing infrastructure anywhere else I've worked.
  • mike_hearn 1y ago
    Yeah Google's infrastructure is unique because Blaze is tightly integrated with the remote execution workers and can shard testing work across many machines automatically. Most places can't do that so once you have enough hardware that queue depth isn't too big you can't make anything go faster by adding hardware, you can only try to scale vertically or optimize. But if you're using hosted CI SaaS it's often not always easy to get bigger machines, or the bigger machines are superlinear in cost.
• socalgal2 1y ago
  Even Google can not buy more old Intel Macs or Pixel 6s or Samsung S20s to increase their testing on those devices (as an example) Maybe that affects less devs who don't need to test on actual hardware but plenty of apps do. Pretty much anything that touches a GPU driver for example like a game.
• anp 1y ago
  I’m currently at google (opinions not representative of my employer’s etc) and this is true for things that run in a data center but it’s a lot harder for things that need to be tested on physical hardware like parts of Android or CrOS.
• wavemode 1y ago
  You're confusing throughput and latency. Lengthy CI runs increase the latency of developer output, but they don't significantly reduce overall throughput, given a developer will typically be working on multiple things at once, and can just switch tasks while CI is running. The productivity cost of CI is not zero, but it's way, way less than the raw wallclock time spent per run. Then also factor in that most developer tasks are not even bottlenecked by CI. They are bottlenecked primarily by code review, and secondarily by deployment.
  • mike_hearn 1y ago
    Length CI runs do reduce throughput, as working around high CI latencies pushes people towards juggling more PRs at once meaning more merge conflicts to deal with, and increases the cost of a build failing transiently. And context switching isn't free by any means. Still, if LLM agents keep improving then the bottleneck of waiting on code review won't exist for the agents themselves, there'll just be a stream of always-green branches waiting for someone to review and merge them. CI costs will still matter though.
    • wavemode 1y ago
      Yes my comment explicitly states that the cost is not zero
• kevingadd 1y ago
  My personal experience: We run over 1.1m test cases to verify every PR that I submit, and there are more test cases that don't get run on every commit and instead get run daily or on-demand. At that scale getting quick turnaround is a difficult infrastructure problem, especially if you have individual tests that take multiple seconds or suites that take multiple minutes (we do, and it's hard to actually pull the execution time down on all of them). I've never personally heard "we don't have the budget" or "we don't have enough machines" as answers for why our CI turnaround isn't 5 minutes, and it doesn't seem to me like the answer is just doubling the core count in every situation. The scenario I work on daily (a custom multi-platform runtime with its own standard library) does by necessity mean that builds and testing are fairly complex though. I wouldn't be surprised if your assertion (just throw more resources at it) holds for more straightforward apps.
• fy20 1y ago
  My last company was unsure about paying $20/mo to get a Copilot license for all the engineers.
  • KronisLV 1y ago
    I've seen people not pay for Slack and just deal with disappearing messages and use Skype (back in the day) for group calls.
• noelwelsh 1y ago
  I believe the solution is to run CI locally, and upload some signed proof that CI completed successfully. Running the same tests locally and then on an ~10 times slower CI build always felts like a ridiculous waste of time to me.
• joshstrange 1y ago
  > I don't understand this. Developer time is so much more expensive than machine time. Do companies not just double their CI workers after hearing people complain? They don’t, and it’s annoying. Oh some do for sure but it’s the same with developer hardware. I’ve worked places where developers are waiting 4+ minutes for a build to complete when that could be halved or more by better developer hardware but companies are sometimes incredibly “penny wise and pound foolish”.