4 ms·

Yes, but HotSpot G1 is meant to be usable with only a single knob too (target pause time). Other knobs do exist, but only for unusual cases where you want to pr

Yes, but HotSpot G1 is meant to be usable with only a single knob too (target pause time). Other knobs do exist, but only for unusual cases where you want to precisely control the GC's operation to work around some bad app/gc interaction, for instance. And Go lacking such knobs is probably not really a feature: it's not like the Java guys set out from the start saying "we will build a complicated and hard to configure GC". It's just that as you work through more and more customer cases, these knobs become valuable for the hard ones.

jerf 10y ago
The point is not that lacking knobs is a feature. The point is that the designers are well aware of the issues and they are explicitly making it a goal that knobs should be unnecessary. (Especially since it has had some knobs off and on in the various versions, as mentioned in the article.) This is in contrast to something we've probably all done at one point or another, which is just to add a checkbox to avoid having an argument about what the behavior should be. They're committing to having the argument out instead of "just adding knobs". They also have a track record of, for better or worse, just refusing to add knobs and telling you to either do without or use a different language. If you've got an intensely GC-based workload, I'd consider using something other than Go. (However, bear in mind what may be an intensely GC-based workload in Java may not be in Go, since Go has value types already.)
- pcwalton 10y ago
  HotSpot cares a lot about proper defaults too. I don't think that there's a significant philosophy difference between HotSpot and Go there. The philosophy difference is, as you say, that Go is opposed to adding configuration options, while HotSpot does have those options (per customers' requests).
tmd83 10y ago
I have seen how G1 suppose to have this one flag but I often get a bad feeling about G1 (without really using it much). It seems it reduces average GC pauses but performs really bad in the really lower (CMS) range. One of thing that looked bad to me is that originally they believed that it can completely ignore the generational hypothesis and then had to brought that back when finding the performance bad. There are also other issues like cross region links that it doesn't handle well. It seems to me that they thought their regional idea was a silver bullet and now tweaking it all over the place. It is a nice GC probably but I don't think its really the GC to end all other GC like Oracle wants it to be.

jerf 10y ago

The point is not that lacking knobs is a feature. The point is that the designers are well aware of the issues and they are explicitly making it a goal that knobs should be unnecessary. (Especially since it has had some knobs off and on in the various versions, as mentioned in the article.) This is in contrast to something we've probably all done at one point or another, which is just to add a checkbox to avoid having an argument about what the behavior should be. They're committing to having the argument out instead of "just adding knobs". They also have a track record of, for better or worse, just refusing to add knobs and telling you to either do without or use a different language. If you've got an intensely GC-based workload, I'd consider using something other than Go. (However, bear in mind what may be an intensely GC-based workload in Java may not be in Go, since Go has value types already.)

pcwalton 10y ago
HotSpot cares a lot about proper defaults too. I don't think that there's a significant philosophy difference between HotSpot and Go there. The philosophy difference is, as you say, that Go is opposed to adding configuration options, while HotSpot does have those options (per customers' requests).

tmd83 10y ago

I have seen how G1 suppose to have this one flag but I often get a bad feeling about G1 (without really using it much). It seems it reduces average GC pauses but performs really bad in the really lower (CMS) range. One of thing that looked bad to me is that originally they believed that it can completely ignore the generational hypothesis and then had to brought that back when finding the performance bad. There are also other issues like cross region links that it doesn't handle well. It seems to me that they thought their regional idea was a silver bullet and now tweaking it all over the place. It is a nice GC probably but I don't think its really the GC to end all other GC like Oracle wants it to be.