Hi, On Saturday, November 26, 2011 04:52:50 PM Pavan Deolasee wrote: > I think now that we have reduced the run time of the function itself, > we should now try to reduce the number of times the function is > called. Robert proposed a way to reduce the number of calls per > transaction. I think we can go one more step further and reduce the > number for across the transactions. You could also try if it makes a difference reducing SnapshotData to one instead of two cachelines. The data itself fits into one without problems. Trivial patch attached.
Generally I think we should check that for most of the more commonly used strutures, we have many with too much padding. Andres
diff --git a/src/include/utils/snapshot.h b/src/include/utils/snapshot.h index 859e52a..b9c2209 100644 --- a/src/include/utils/snapshot.h +++ b/src/include/utils/snapshot.h @@ -46,13 +46,14 @@ typedef struct SnapshotData */ TransactionId xmin; /* all XID < xmin are visible to me */ TransactionId xmax; /* all XID >= xmax are invisible to me */ - uint32 xcnt; /* # of xact ids in xip[] */ TransactionId *xip; /* array of xact IDs in progress */ + uint32 xcnt; /* # of xact ids in xip[] */ /* note: all ids in xip[] satisfy xmin <= xip[i] < xmax */ int32 subxcnt; /* # of xact ids in subxip[] */ TransactionId *subxip; /* array of subxact IDs in progress */ bool suboverflowed; /* has the subxip array overflowed? */ bool takenDuringRecovery; /* recovery-shaped snapshot? */ + bool copied; /* false if it's a static snapshot */ /* * note: all ids in subxip[] are >= xmin, but we don't bother filtering @@ -61,7 +62,6 @@ typedef struct SnapshotData CommandId curcid; /* in my xact, CID < curcid are visible */ uint32 active_count; /* refcount on ActiveSnapshot stack */ uint32 regd_count; /* refcount on RegisteredSnapshotList */ - bool copied; /* false if it's a static snapshot */ } SnapshotData; /*
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