Re: [Qemu-devel] [PATCH v4 06/14] qemu-thread: add simple test-and-set spinlock

2016-05-03 Thread Richard Henderson
On 04/29/2016 05:33 PM, Emilio G. Cota wrote: From: Guillaume Delbergue Signed-off-by: Guillaume Delbergue [Rewritten. - Paolo] Signed-off-by: Paolo Bonzini [Emilio's additions: use atomic_test_and_set instead of atomic_xchg; call cpu_relax() while spinning; optimize for uncontended locks by

[Qemu-devel] [PATCH v4 06/14] qemu-thread: add simple test-and-set spinlock

2016-04-29 Thread Emilio G. Cota
From: Guillaume Delbergue Signed-off-by: Guillaume Delbergue [Rewritten. - Paolo] Signed-off-by: Paolo Bonzini [Emilio's additions: use atomic_test_and_set instead of atomic_xchg; call cpu_relax() while spinning; optimize for uncontended locks by acquiring the lock with TAS instead of TATAS.]