Oracle Database Discussions

Last week i hit the library cache contention. sessions rapidly increased, although NO CPU overhead at all.
Following is the AWR report taken during the case.
It was the first time we came across the such as library cache contention case.
"latch:library cache" event takes %68 of the overall.
What may be the reason.
Thanks,
session_cached_cursors=250
shared_pool_size=2600M
sga_max_size=5000M
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library cache kglpin 0 94,909 38,586
library cache kglpndl: child: after processing 0 42,500 287
library cache kgldti: 2child 0 39,297 2,559
library cache kglScanDependency 0 37,224 3
library cache kglhdiv0: parent: invalidate 0 36,633 190
library cache kglic 0 24,163 13,090
library cache kglobpn: child: 0 21,972 86,553
library cache kglLockCursor 0 19,794 45,910
library cache kglhdgn: child: 0 10,984 49,233
library cache kgldte: child 0 0 9,180 55,232
library cache kglpndl: child: before processing 0 9,136 53,165
library cache kglpnp: child 0 7,538 35,102