| e76d1798 | 10-Mar-2016 |
Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> |
icount: decouple warp calls
qemu_clock_warp function is called to update virtual clock when CPU
is sleeping. This function includes replay checkpoint to make execution
deterministic in icount mode.
icount: decouple warp calls
qemu_clock_warp function is called to update virtual clock when CPU
is sleeping. This function includes replay checkpoint to make execution
deterministic in icount mode.
Record/replay module flushes async event queue at checkpoints.
Some of the events (e.g., block devices operations) include interaction
with hardware. E.g., APIC polled by block devices sets one of IRQ flags.
Flag to be set depends on currently executed thread (CPU or iothread).
Therefore in replay mode we have to process the checkpoints in the same thread
as they were recorded.
qemu_clock_warp function (and its checkpoint) may be called from different
thread. This patch decouples two different execution cases of this function:
call when CPU is sleeping from iothread and call from cpu thread to update
virtual clock.
First task is performed by qemu_start_warp_timer function. It sets warp
timer event to the moment of nearest pending virtual timer.
Second function (qemu_account_warp_timer) is called from cpu thread
before execution of the code. It advances virtual clock by adding the length
of period while CPU was sleeping.
Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20160310115609.4812.44986.stgit@PASHA-ISP>
[Update docs. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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| 8eda206e | 17-Sep-2015 |
Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru> |
replay: recording and replaying clock ticks
Clock ticks are considered as the sources of non-deterministic data for
virtual machine. This patch implements saving the clock values when they
are acqui
replay: recording and replaying clock ticks
Clock ticks are considered as the sources of non-deterministic data for
virtual machine. This patch implements saving the clock values when they
are acquired (virtual, host clock).
When replaying the execution corresponding values are read from log and
transfered to the module, which wants to read the values.
Such a design required the clock polling to be synchronized. Sometimes
it is not true - e.g. when timeouts for timer lists are checked. In this case
we use a cached value of the clock, passing it to the client code.
Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
Message-Id: <20150917162427.8676.36558.stgit@PASHA-ISP.def.inno>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Pavel Dovgalyuk <Pavel.Dovgaluk@ispras.ru>
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