FreeBSD 10.0-R as Xen 'guest' - clarification?

[Colin Percival]

On 02/11/14 09:26, Justin T. Gibbs wrote:
> On Jan 29, 2014, at 8:28 AM, Karl Pielorz <kpielorz_lst at tdx.co.uk> wrote:
>> The man page for xen (man 4 xen) states you should have:
>>
>> options NO_ADAPTIVE_MUTEXES
>> options NO_ADAPTIVE_RWLOCKS
>> options NO_ADAPTIVE_SX
> 
> The “NO_ADAPTIVE” settings are an optimization when running in environments where different guests run on the same physical CPU.  However, many cloud providers seem to statically pin CPUs to VMs, which means the adaptive lock optimization works as expected.

... and with static pinning, adding the NO_ADAPTIVE_FOO options causes a
significant drop in performance, so you really don't want them unless you're
going to be sharing CPUs.

-- 
Colin Percival
Security Officer Emeritus, FreeBSD | The power to serve
Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid