4 ms·

I d simply take a noop GC in the most recent jvm (I cant yet in my conservative bank), and make people suffer through it in prod until everything is constrained

by xwolfi 5y ago

I d simply take a noop GC in the most recent jvm (I cant yet in my conservative bank), and make people suffer through it in prod until everything is constrained correctly, but you're right, String are banned where I work, and what a pain it has to be to do everything via char buffer but it's taking a dev like maybe 10 minutes per "String" handling instead of 5 second during code writing (to massage the buffer all the way from the input signal to the output destination, be it a log file, a storage structure, a comparator or a map key), so it's a giganormous increase of dev time relatively, but in absolute time it's quite trivial over the last 20 years. Yeah we wasted time per feature on String handling but... like maybe a few hours per feature per dev and we generate billions out of the trading backend so... Maybe Java had the wrong assumption and really should just have made C-string optional first class citizens or something. One thing is sure though, our C++ colleagues in the algo team are so slow to deliver, so prone to crazy bugs, so wild and wizardy, so unable to onboard new joiners, they re getting replaced this year by... a brand new Java algo engine... So not sure what to think.

FpUser 5y ago
Initially Java has been created with totally different application scope in mind comparatively to what it is now. I know it may look like a mess but maybe they should've added new optimized string type in addition to already available. As for C++ - I do just that. All my servers are C++ and while I will not claim "bug free" I do not really remember when was the last time I've had memory related bug (alloc / boundary / use after free / etc). Modern C++ along with sanitizers helps greatly in this department. All fixed bugs were logical. I did my share of Java development big while ago and got sick of trying to make it performant enough. In order for me to achieve the goal I've spent way more time caring about memory / resource related issues in Java than I would do in "dangerous languages. Granted it was high performance servers. Doing different type of task in Java could've cost way less aggravation.
ncmncm 5y ago
I know exactly what to think: salaries offered for your C++ colleagues are not competitive, so you are collecting competitors' dregs. It can be very hard to come back from that, maybe impossible. In other shops, the notion of conducting trading in Java, GC'd or no, would get you laughed from the room. But Java coders certainly are cheaper.
- pjmlp 5y ago
  The City in London is full of people with humour and deep pockets.
  - xwolfi 5y ago
    I m in Asia, we need the ability to validate 13 different exchange regulations and Java helps more than C++ as far as I can observe in team work, modularity, forcing some sort of okay common practice etc. The guys in the US have it easy with regard to logic so can throughput fast enough in Java to only switch fast clients to FPGA without the need for C++ in between. The guys in London have nowhere near the volumes of APAC or the US. They can trade with excel if they want.
    - pjmlp 5y ago
      Might be, doesn't change the fact that plenty of business in finance have moved into GC based languages, reducing their use of C++ into niche use cases. Just like using C or C++ hasn't taken away that some niche use cases still require coding in Assembly. It isn't only Java, C#, F#, Haskell and OCaml are also tooling they reach for.
- xwolfi 5y ago
  Well we do Java for the slow path and fpga for the fast path. C++ for the algo decisions, but even when we do java we jni everything that would be slower than C++. Nobody's laughing, everyone is just profiling and fitting constraints, so far Java worked, we ll switch if we must... Problem with FPGA is that it s pointless to try to correct client mistakes or validate exchange regulation with it, so it's only for upstreams who have the whole chain clean, it's a slow transition.
  - cmrdporcupine 5y ago
    See now this all sounds very interesting and exciting. I love both FPGA and C++. Too bad it's finance :-)

by xwolfi 5y ago

FpUser 5y ago

Initially Java has been created with totally different application scope in mind comparatively to what it is now. I know it may look like a mess but maybe they should've added new optimized string type in addition to already available. As for C++ - I do just that. All my servers are C++ and while I will not claim "bug free" I do not really remember when was the last time I've had memory related bug (alloc / boundary / use after free / etc). Modern C++ along with sanitizers helps greatly in this department. All fixed bugs were logical. I did my share of Java development big while ago and got sick of trying to make it performant enough. In order for me to achieve the goal I've spent way more time caring about memory / resource related issues in Java than I would do in "dangerous languages. Granted it was high performance servers. Doing different type of task in Java could've cost way less aggravation.

ncmncm 5y ago

I know exactly what to think: salaries offered for your C++ colleagues are not competitive, so you are collecting competitors' dregs. It can be very hard to come back from that, maybe impossible. In other shops, the notion of conducting trading in Java, GC'd or no, would get you laughed from the room. But Java coders certainly are cheaper.

pjmlp 5y ago
The City in London is full of people with humour and deep pockets.
- xwolfi 5y ago
  I m in Asia, we need the ability to validate 13 different exchange regulations and Java helps more than C++ as far as I can observe in team work, modularity, forcing some sort of okay common practice etc. The guys in the US have it easy with regard to logic so can throughput fast enough in Java to only switch fast clients to FPGA without the need for C++ in between. The guys in London have nowhere near the volumes of APAC or the US. They can trade with excel if they want.
  - pjmlp 5y ago
    Might be, doesn't change the fact that plenty of business in finance have moved into GC based languages, reducing their use of C++ into niche use cases. Just like using C or C++ hasn't taken away that some niche use cases still require coding in Assembly. It isn't only Java, C#, F#, Haskell and OCaml are also tooling they reach for.
xwolfi 5y ago
Well we do Java for the slow path and fpga for the fast path. C++ for the algo decisions, but even when we do java we jni everything that would be slower than C++. Nobody's laughing, everyone is just profiling and fitting constraints, so far Java worked, we ll switch if we must... Problem with FPGA is that it s pointless to try to correct client mistakes or validate exchange regulation with it, so it's only for upstreams who have the whole chain clean, it's a slow transition.
- cmrdporcupine 5y ago
  See now this all sounds very interesting and exciting. I love both FPGA and C++. Too bad it's finance :-)