review for 7029167: add support for conditional card marks

[Igor Veresov]

Thanks!

igor

On 3/30/11 5:38 PM, Tom Rodriguez wrote:
>
> On Mar 30, 2011, at 5:35 PM, Igor Veresov wrote:
>
>> On 3/30/11 5:33 PM, Tom Rodriguez wrote:
>>>
>>> On Mar 30, 2011, at 5:25 PM, Igor Veresov wrote:
>>>
>>>> Looks good.
>>>
>>> Thanks!
>>>
>>>> Could you use CardTableModRefBS::dirty_card_val() instead of 0? I know we use just zero already in many places, but I'm fresh from barrier experimentation and it would've been much nicer if we used symbolic names.
>>>
>>> I'd rather not.  If we really want to use dirty_card_val then it should be done everywhere as its own change instead of just patching part of C2.
>>>
>>
>> May be a comment then, saying that ConI(0) represents dirty_card ? Just for the sake of future grepping?
>
> Ok.
>
>    BasicType bt = T_BYTE;
>    Node*   zero = __ ConI(0); // Dirty card value
>
>    if (UseCondCardMark) {
>
> tom
>
>>
>> igor
>>
>>> tom
>>>
>>>>
>>>>
>>>> igor
>>>>
>>>> On 3/30/11 4:46 PM, Tom Rodriguez wrote:
>>>>> http://cr.openjdk.java.net/~never/7029167
>>>>>
>>>>> 7029167: add support for conditional card marks
>>>>> Reviewed-by:
>>>>>
>>>>> Repeated updates to the card table can be a source of contention on
>>>>> multiprocessor machines that can greatly inhibit scalability.  This
>>>>> adds support in C2 for conditional card marks.  Tested with jbb and
>>>>> CTW.  At some point this should be turned on automatically when multi
>>>>> socket machines are detected but that's covered under another bug as
>>>>> is C1 support.
>>>>>
>>>>
>>>
>>
>