RFR(XXXS): 7168294: G1: Some Full GCs incorrectly report GC cause as "No GC"

[Srinivas Ramakrishna]

Looks good to me.

-- ramki

Sent from my iPhone

On May 11, 2012, at 3:37 PM, John Cuthbertson <john.cuthbertson at oracle.com> wrote:

> Hi Everyone,
> 
> Can I have a couple of volunteers review this code change? The webrev can be found at: http://cr.openjdk.java.net/~johnc/7168294/webrev.0/
> 
> Summary:
> Basically the VM_G1CollectForAllocation VM operation was not setting the GC cause in the heap structure and so the cause would come out as "No GC". This one line change makes VM_G1CollectForAllocation match the other 'leaf' G1 VM operations.
> 
> Testing: GCOld
> 
> Before:
> 
> 9.239: [Full GC (No GC) 128M->125M(128M), 9.0804393 secs]
> 18.837: [Full GC (No GC) 127M->127M(128M), 7.9413652 secs]
> 26.778: [Full GC (No GC) 127M->127M(128M), 7.9419157 secs]
> 34.731: [Full GC (No GC) 127M->127M(128M), 8.0385112 secs]
> 42.770: [Full GC (No GC) 127M->127M(128M), 7.9215393 secs]
> 50.702: [Full GC (No GC) 127M->127M(128M), 9.0424004 secs]
> 59.744: [Full GC (No GC) 127M->127M(128M), 7.9409172 secs]
> 
> After:
> 
> 9.357: [Full GC (Allocation Failure) 128M->125M(128M), 9.1094425 secs]
> 18.976: [Full GC (Allocation Failure) 127M->127M(128M), 7.9846687 secs]
> 26.961: [Full GC (Allocation Failure) 127M->127M(128M), 7.9409885 secs]
> 34.913: [Full GC (Allocation Failure) 127M->127M(128M), 8.0551207 secs]
> 42.968: [Full GC (Allocation Failure) 127M->127M(128M), 7.9402328 secs]
> 50.919: [Full GC (Allocation Failure) 127M->127M(128M), 9.0121452 secs]
> 59.932: [Full GC (Allocation Failure) 127M->127M(128M), 7.9184263 secs]
> 
> Thanks,
> 
> JohnC