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Revert "replay: stop us hanging in rr_wait_io_event"

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This reverts commit 1f881ea4a4.

That commit causes reverse_debugging.py test failures, and does
not seem to solve the root cause of the problem x86-64 still
hangs in record/replay tests.

The problem with short-cutting the iowait that was taken during
record phase is that related events will not get consumed at the
same points (e.g., reading the clock).

A hang with zero icount always seems to be a symptom of an earlier
problem that has caused the recording to become out of synch with
the execution and consumption of events by replay.

Acked-by: Alex Bennée <alex.bennee@linaro.org>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Message-Id: <20240813050638.446172-6-npiggin@gmail.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20240813202329.1237572-14-alex.bennee@linaro.org>
This commit is contained in:
Nicholas Piggin 2024-08-13 21:23:21 +01:00 committed by Alex Bennée
parent 9dbab31d9e
commit 94962ff00d
3 changed files with 1 additions and 27 deletions
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2
accel/tcg/tcg-accel-ops-rr.c
View File

@ -109,7 +109,7 @@ static void rr_wait_io_event(void)
{ {
CPUState *cpu; CPUState *cpu;
while (all_cpu_threads_idle() && replay_can_wait()) { while (all_cpu_threads_idle()) {
rr_stop_kick_timer(); rr_stop_kick_timer();
qemu_cond_wait_bql(first_cpu->halt_cond); qemu_cond_wait_bql(first_cpu->halt_cond);
} }

5
include/sysemu/replay.h
View File

@ -73,11 +73,6 @@ int replay_get_instructions(void);
/*! Updates instructions counter in replay mode. */ /*! Updates instructions counter in replay mode. */
void replay_account_executed_instructions(void); void replay_account_executed_instructions(void);
/**
* replay_can_wait: check if we should pause for wait-io
*/
bool replay_can_wait(void);
/* Processing clocks and other time sources */ /* Processing clocks and other time sources */
/*! Save the specified clock */ /*! Save the specified clock */

21
replay/replay.c
View File

@ -451,27 +451,6 @@ void replay_start(void)
replay_enable_events(); replay_enable_events();
} }
/*
* For none/record the answer is yes.
*/
bool replay_can_wait(void)
{
if (replay_mode == REPLAY_MODE_PLAY) {
/*
* For playback we shouldn't ever be at a point we wait. If
* the instruction count has reached zero and we have an
* unconsumed event we should go around again and consume it.
*/
if (replay_state.instruction_count == 0 && replay_state.has_unread_data) {
return false;
} else {
replay_sync_error("Playback shouldn't have to iowait");
}
}
return true;
}
void replay_finish(void) void replay_finish(void)
{ {
if (replay_mode == REPLAY_MODE_NONE) { if (replay_mode == REPLAY_MODE_NONE) {