RFR(XXXS): 7194409: os::javaTimeNanos() shows hot on CPU_CLK_UNHALTED profiles

[Azeem Jiva]

Looks good to me

Azeem Jiva
@javawithjiva

On 08/28/2012 12:58 PM, John Cuthbertson wrote:
> Hi Everyone,
>
> Can I have another volunteer to review the changes for this CR (which 
> were contributed by Brandon Mitchell at Twitter)? The webrev can be 
> found at: http://cr.openjdk.java.net/~johnc/7194409/webrev.0/
>
> Here's the description, according to Brandon:
>
>> os::javaTimeNanos() shows hot on CPU_CLK_UNHALTED profiles due to
>> unnecessary function setup/teardown code around
>> Linux::supports_monotonic_clock(). I've added an inline annotation to
>> simplify the funcall to a NULL check, and verified the change using
>> both gdb disas and additional profiling. I observed a 2-3% CPU time
>> delta in my profile data for os::javaTimeNanos().
> Thanks,
>
> JohnC

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