Re: [Xen-devel] [PATCHv2 3/3] p2m: convert grant table rwlock to percpu rwlock

2015-11-25 Thread George Dunlap
On 20/11/15 16:03, Malcolm Crossley wrote: > The per domain p2m read lock suffers from significant contention when > performance multi-queue block or network IO due to the parallel > grant map/unmaps/copies occuring on the DomU's p2m. > > On multi-socket systems, the contention results in the

Re: [Xen-devel] [PATCHv2 3/3] p2m: convert grant table rwlock to percpu rwlock

2015-11-25 Thread Jan Beulich
>>> On 20.11.15 at 17:03, wrote: > @@ -115,7 +117,7 @@ static inline void _mm_write_lock(mm_rwlock_t *l, const > char *func, int level) > if ( !mm_write_locked_by_me(l) ) > { > __check_lock_level(level); > -write_lock(>lock); > +

Re: [Xen-devel] [PATCHv2 3/3] p2m: convert grant table rwlock to percpu rwlock

2015-11-25 Thread Malcolm Crossley
On 25/11/15 12:38, Jan Beulich wrote: On 20.11.15 at 17:03, wrote: >> @@ -115,7 +117,7 @@ static inline void _mm_write_lock(mm_rwlock_t *l, const >> char *func, int level) >> if ( !mm_write_locked_by_me(l) ) >> { >> __check_lock_level(level);

[Xen-devel] [PATCHv2 3/3] p2m: convert grant table rwlock to percpu rwlock

2015-11-20 Thread Malcolm Crossley
The per domain p2m read lock suffers from significant contention when performance multi-queue block or network IO due to the parallel grant map/unmaps/copies occuring on the DomU's p2m. On multi-socket systems, the contention results in the locked compare swap operation failing frequently which