[Qemu-devel] [PATCH v2 0/4] RTC: New logic to emulate RTC

[Zhang, Yang Z]

Changes in v2:
Add UIP check logic.
Add logic that next second tick will occur in exactly 500ms later after setting 
the clock

Current RTC emulation uses periodic timer(2 timers per second) to update RTC 
clock. And it will stop CPU staying at deep C-state for long period. Our 
experience shows the Pkg C6 residency reduced 6% when running 64 idle guest.
The following patch stop the two periodic timer and only updating RTC clock 
when guest try to read it.

--- 
Yang Zhang (4):
        RTC: Update the RTC clock only when reading it
        RTC: Add RTC update-ended interrupt support
        RTC: Add alarm support
        RTC: Add UIP(update in progress) check logic

        hw/mc146818rtc.c |  447 
+++++++++++++++++++++++++++++++++++++-----------------
        1 files changed, 308 insertions(+), 139 deletions(-)

best regards
yang