Change Details

Misbehavior has been oserved with TSC under VirtualBox, where threads doing small sleeps (~1 second) may miss their wake up and hang around in a sleep state indefinitely. Switching back to ACPI-fast decidedly fixes it, so stop using TSC on VirtualBox at least for the time being. This partially reverts 84eaf2ccc6aa, applying it only to VirtualBox. MFC after: 3 days

Misbehavior has been observed with TSC under VirtualBox, where threads doing small sleeps (~1 second) may miss their wake up and hang around in a sleep state indefinitely. Switching back to ACPI-fast decidedly fixes it, so stop using TSC on VirtualBox at least for the time being. This partially reverts 84eaf2ccc6aa, applying it only to VirtualBox. MFC after: 3 days

Misbehavior has been observed with TSC under VirtualBox, where threads doing small sleeps (~1 second) may miss their wake up and hang around in a sleep state indefinitely. Switching back to ACPI-fast decidedly fixes it, so stop using TSC on VirtualBox at least for the time being. This partially reverts 84eaf2ccc6aa, applying it only to VirtualBox. MFC after: 3 days