Proposal for improving performance of TreeMap and others

Clemens Eisserer linuxhippy at
Mon Jan 7 22:38:11 UTC 2008

Hi cowwoc,

> I guess you're right. It is probably as likely that the JIT will optimize
> away the null check as it is that it will optimize away the
> NullPointerException check. One exception, though, is when production
> systems run using -Xverify:none. In such a case, wouldn't my approach run
> faster?
I don't think it will optimize the null-check away, however it is so
cheap that it most likely will not weight at all, compared to all the
other operations happening there. Its maybe 5 instructions compared to
thousands or even more.
-Xverify:none only disables bytecode verification at class-loading
time and has no influence (as far as I know) on the performance of the
generated code.

> I still think that my proposed code is somehow more consistent/cleaner on a
> design-level but I guess that's just me :)
I also like it more, its cleaner in my opinion :)

> As an aside, are there standard benchmarks for testing the impact of this
> change? I'd love to know whether it actually produces any performance
> difference in practice.
>From my experience i would rather guess that you won't notice the
change, noise will be higher.

lg Clemens

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