Proposal for improving performance of TreeMap and others
forax at univ-mlv.fr
Mon Jan 7 23:38:34 UTC 2008
Clemens Eisserer a écrit :
> 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
> I don't think it will optimize the null-check away,
Hotspot removes nullcheck and install a signal handler since its v2
(around 2000/01 If my memory serves me well).
> 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.
yes, and there is an option to remove nullcheck that is only available
on debug VM.
> lg Clemens
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