How I cut GTA Online loading times by 70%

Doesn't surprise me at all. It's an O(n^2) algorithm (strlen called in a loop) in a part of the code where N is likely much smaller in the test environment (in-app purchases).

Overwatch is another an incredibly popular game with obvious bugs (the matchmaking time) front and center. And gamers are quick to excuse it as some sort of incredibly sophisticated matchmaking - just like the gamers mentioned in OP.

It's easy to to say it's something about gamers / gaming / fandom - but I have a locked down laptop issued by my bigcorp which is unbelievably slow. I'd bet a dollar there's a bug in the enterprise management software that spins the CPU. A lot of software just sucks and people use it anyway.

I am not sure Overwatch's matchmaking time is a bug per se. The time estimates are bad for sure. But the matchmaker can really only be sure of one state -- if you queue for a match, a match will be made. The rest is predicting who will show up, along with some time-based scale for making a suboptimal match in the interest of time. Players absolutely hate these suboptimal matches, so the time threshold ends up being pretty high. The rest seems to just be luck; will the right combination of 11 other people be in the right place at the right time?

I think it could be improved, but it doesn't strike me as being buggy.

(Overwatch itself, lots of bugs. Tons of bugs. If they have any automated tests for game mechanics I would be pretty surprised.)

No, it doesn't add up. I can see dozens of groups filling up and queueing at my groups level as I wait for matches. Worse, many of my matches just aren't that evenly balanced. Even if you believe the game is dead now, things were just as bad (10+ minute queues for full 6 stacks) at the peak. They don't do tight geographic bindings - I live on the US west coast and regularly get Brits and Aussies in my games.

I guess what they are probably doing is batching groups of games and then matching for the entire batch, to ensure nobody gets a "bad" match. What they've missed is that well - 5% of matches are bad baseline because somebody is being a jerk or quits or has an internet disconnect or smurfs or whatever other reasons. They could have picked an algorithm that gave fast matches 99% of the time at the cost of having bad matches 1% of the time and nobody would have noticed, because their baseline bad match rate is so high. Optimization from too narrow a perspective.

Honestly, the OW matches I get aren't any more balanced that the COD matches I used to get, and I got those in a minute, not 15.

I think that player variance is the hardest thing for the matchmaker to account for, and a factor that makes a big difference in the quality of the match. Bronze duo'd with Top 500 is always a shit show, even if the other team has the same duo. It don't think it can be made to work.

(My experience shows this is the case; quickplay matches, with no grouping restrictions, are always more of a shitshow than ranked, which has some grouping restrictions.)

Similarly, an individual's performance variance makes a big difference that a mere arithmetic average can't account for. A 3900 player probably plays like a 4100 player when fresh and warmed up, but like a 3500 player when drunk, sleepy, and mad. The actual SR/MMR will converge to a time weighted average of those two states, but if you're in a 4100 game with that player when they're in their 3500 state, it's probably unwinnable. Maybe the matchmaker could attempt to predict this, but it would probably make people mad. Personally, I think that's the nature of a 12 person game composed of 12 randos. There is very little an algorithm can do to tune that (short of changing abilities/hitboxes/cooldowns of each player, which would make people mad).

Then there are people that abuse the matchmaker by exploiting uncertainty in their favor (creating a new account). Every time I have played in a 6 stack in ranked, we've always played against 6 brand new accounts that are clearly better than the matchmaker thinks they are, which sucks. (In quickplay, I generally have very good games in a 6 stack though.)

Overall, I hate to say this, but I think they're doing the best they can. I don't think there's enough data to make a good match 100% of the time, which is why people find 11 players and play "scrims" instead of ranked/quickplay. I don't know where you're able to see other groups and decide that they're a suitable match -- 90% of players have private profiles, and those that don't only play like 10 ranked games a season, so you can't really gauge how good or bad they are from public data.

(As for brits and aussies joining your west coast games... people VPN in to do that on purpose. Legend has it that west coast gamers are better than east coast gamers, so people all over the world VPN to the west coast and make it a self-fulfilling prophecy.)

I think you might be missing my point. Maybe an analogy - the classic problem in distributed database is CAP - consistency, availability, partition tolerance - pick two. Historically, a lot of people picked AP to build their highly available databases. In the context of Spanner, Google basically said this was the wrong tradeoff - availability is more highly impacted by external events like client to server networking incidents than by the design architecture - so you should pick CP instead.

I'm making the same point with regard to matchmaking. Overwatch has tried to optimize for good matches, ignoring all the issues you rightly describe above, and thinking about the tradeoff between time and good matches without regard to external events that impact matches like smurfs, uneven play, DCs, etc. They'd have been better off optimizing for fast matchmaking. It's bad engineering in plain sight, and gamers go out of their way to justify it.