JDK10 RFR: 8165437 Evaluate the use of gettimeofday in Networking code

[Vyom Tewari]

On Wednesday 12 April 2017 11:05 PM, Vyom Tewari wrote:
>
> Hi Roger,
>
> thanks for review, please see my  comment inline.
>
> Vyom
>
>
> On Wednesday 12 April 2017 08:17 PM, Roger Riggs wrote:
>> Hi Vyom,
>>
>> Thanks for taking this on.   I have a few comments and questions.
>>
>> In aix_close.c line 547 The code for if (nanoTimeout >= 
>> NSEC_PER_MSEC) seems ineffective.
>>
> agreed, but this check was previously there(timeout > 0) and this 
> check will prevent the additional call to 
> "JVM_NanoTime/gettimeofday()" in modified code. I think  we leave this 
> check as it is and put the corresponding else block. Please do let me 
> know your thought on this.
i think you got it right, the "if" at line 547 is ineffective.
Vyom
>> The update of nanoTime at 549-550 ensures the timeout is > 
>> NSEC_PER_MSEC if it loops.
>> On the first pass through the code if nanoTimeout was < NSEC_PER_MSEC 
>> it would
>> poll with a timeout of zero which returns immediately, EINTR is not 
>> possible.
>>
>> The comment at 546 would be inaccurate if nanoTimeout is too small, 
>> because it will loop again.
>>
> right, this is on wrong place it has to be in inner if block. I put 
> this comment to avoid the confusion why "nanoTimeout < NET_NSEC_PER_MSEC".
>> I think the behavior would be the same if the extra condition at 547 
>> is removed.
>>
>> Most of the other xxx_close.c classes have the same structure.
>>
>> PlainSocketImpl.c has the same structure
>>
>>
>> The bsd_close.c had the same kind of before and after checking but 
>> did previously
>> and conservatively I'd keep that structure though I think it was 
>> ineffective in that case too.
>>
>> Thanks, Roger
>>
>>
>>
>>
>> On 4/11/2017 9:04 AM, Vyom Tewari wrote:
>>> Hi,
>>>
>>> Please review the code change for below issue.
>>>
>>> Bug: https://bugs.openjdk.java.net/browse/JDK-8165437
>>>
>>> Webrev: 
>>> http://cr.openjdk.java.net/~vtewari/8165437/webrev0.5/index.html
>>>
>>> This change will replace the "gettimeofday" to use the monotonic 
>>> increasing clock(i used the existing function "JVM_NanoTime" instead 
>>> of writing my own).
>>>
>>> Thanks,
>>>
>>> Vyom
>>>
>>>
>>
>

-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.openjdk.java.net/pipermail/net-dev/attachments/20170412/22ad166c/attachment.html>