RFR 8157318: ThreadedSeedGenerator uses System.currentTimeMillis and stops generating when time is set back

[Weijun Wang]

Ping again.

On 6/16/2016 10:32, Wang Weijun wrote:
>
>> On Jun 16, 2016, at 6:37 AM, David M. Lloyd <david.lloyd at redhat.com> wrote:
>>
>> This will not work because System.nanoTime() can be negative and wrap around.  You can't compare one nanoTime to another, only differences are useful.
>
> Yes, you are right. How about this then?
>
> diff --git a/src/java.base/share/classes/sun/security/provider/SeedGenerator.java b/src/java.base/share/classes/sun/security/provider/SeedGenerator.java
> --- a/src/java.base/share/classes/sun/security/provider/SeedGenerator.java
> +++ b/src/java.base/share/classes/sun/security/provider/SeedGenerator.java
> @@ -354,8 +354,8 @@
>                          // We wait 250milli quanta, so the minimum wait time
>                          // cannot be under 250milli.
>                          int latch = 0;
> -                        long l = System.currentTimeMillis() + 250;
> -                        while (System.currentTimeMillis() < l) {
> +                        long l = System.nanoTime();
> +                        while (System.nanoTime() - l < 250000000) {
>                              synchronized(this){};
>                              latch++;
>                          }
>
> Thanks
> Max
>
>>
>> On 06/15/2016 05:30 PM, Bradford Wetmore wrote:
>>> Looks good, Max, thanks for taking this over.
>>>
>>> Xuelei, it's a threaded accumulator, which feeds into the seed
>>> generator.  We wait a certain amount of time before generating the values.
>>>
>>> Brad
>>>
>>>
>>> On 6/15/2016 5:07 AM, Xuelei Fan wrote:
>>>> I'm not sure I understand the while loop.  But this update looks fine to
>>>> me as it does not change the logic of the code except to use elapsed
>>>> time.
>>>>
>>>> Xuelei
>>>>
>>>> On 6/15/2016 11:12 AM, Wang Weijun wrote:
>>>>> Please take a review on the patch
>>>>>
>>>>> diff --git
>>>>> a/src/java.base/share/classes/sun/security/provider/SeedGenerator.java b/src/java.base/share/classes/sun/security/provider/SeedGenerator.java
>>>>>
>>>>> ---
>>>>> a/src/java.base/share/classes/sun/security/provider/SeedGenerator.java
>>>>> +++
>>>>> b/src/java.base/share/classes/sun/security/provider/SeedGenerator.java
>>>>> @@ -354,8 +354,8 @@
>>>>>                         // We wait 250milli quanta, so the minimum
>>>>> wait time
>>>>>                         // cannot be under 250milli.
>>>>>                         int latch = 0;
>>>>> -                        long l = System.currentTimeMillis() + 250;
>>>>> -                        while (System.currentTimeMillis() < l) {
>>>>> +                        long l = System.nanoTime() + 250000000;
>>>>> +                        while (System.nanoTime() < l) {
>>>>>                             synchronized(this){};
>>>>>                             latch++;
>>>>>                         }
>>>>>
>>>>> nanoTime() is for elapsed time and should be used here.
>>>>>
>>>>> Thanks
>>>>> Max
>>>>>
>>>>
>>
>> --
>> - DML
>