timer: update comments

The comments is outdated. The patch has following changes:
1. tense correction.
2. all clock time value is returned in nanoseconds, so, they are same in
precision.
3. virtual clock doesn't use cpu cycles.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Cc: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Cao jin <caoj.fnst@cn.fujitsu.com>
Message-Id: <1469790338-28990-2-git-send-email-caoj.fnst@cn.fujitsu.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Cao jin 2016-07-29 19:05:36 +08:00 committed by Paolo Bonzini
parent 5b1b6dbd94
commit 490ab15a49

View File

@ -22,23 +22,20 @@
* @QEMU_CLOCK_REALTIME: Real time clock
*
* The real time clock should be used only for stuff which does not
* change the virtual machine state, as it is run even if the virtual
* machine is stopped. The real time clock has a frequency of 1000
* Hz.
* change the virtual machine state, as it runs even if the virtual
* machine is stopped.
*
* @QEMU_CLOCK_VIRTUAL: virtual clock
*
* The virtual clock is only run during the emulation. It is stopped
* when the virtual machine is stopped. Virtual timers use a high
* precision clock, usually cpu cycles (use ticks_per_sec).
* The virtual clock only runs during the emulation. It stops
* when the virtual machine is stopped.
*
* @QEMU_CLOCK_HOST: host clock
*
* The host clock should be use for device models that emulate accurate
* The host clock should be used for device models that emulate accurate
* real time sources. It will continue to run when the virtual machine
* is suspended, and it will reflect system time changes the host may
* undergo (e.g. due to NTP). The host clock has the same precision as
* the virtual clock.
* undergo (e.g. due to NTP).
*
* @QEMU_CLOCK_VIRTUAL_RT: realtime clock used for icount warp
*
@ -76,10 +73,6 @@ struct QEMUTimer {
extern QEMUTimerListGroup main_loop_tlg;
/*
* QEMUClockType
*/
/*
* qemu_clock_get_ns;
* @type: the clock type