Re: [Xen-devel] [PATCH 1/2] x86/time: drop vtsc_{kern, user}count debug counters

2019-12-16 Thread Andrew Cooper
On 16/12/2019 09:47, Roger Pau Monné wrote: > On Fri, Dec 13, 2019 at 10:48:01PM +, Igor Druzhinin wrote: >> They either need to be transformed to atomics to work correctly >> (currently they left unprotected for HVM domains) or dropped entirely > ^ are used >> as taking a

Re: [Xen-devel] [PATCH 1/2] x86/time: drop vtsc_{kern, user}count debug counters

2019-12-16 Thread Roger Pau Monné
On Fri, Dec 13, 2019 at 10:48:01PM +, Igor Druzhinin wrote: > They either need to be transformed to atomics to work correctly > (currently they left unprotected for HVM domains) or dropped entirely ^ are used > as taking a per-domain spinlock is too expensive for high-vCPU

[Xen-devel] [PATCH 1/2] x86/time: drop vtsc_{kern, user}count debug counters

2019-12-13 Thread Igor Druzhinin
They either need to be transformed to atomics to work correctly (currently they left unprotected for HVM domains) or dropped entirely as taking a per-domain spinlock is too expensive for high-vCPU count domains even for debug build given this lock is taken too often. Choose the latter as they are