Re: [Qemu-devel] [RFC PATCH v6 09/32] replay: introduce icount event

[Gonglei <arei.gonglei@huawei.com>]

On 2014/12/8 15:53, Pavel Dovgalyuk wrote:

> This patch adds icount event to the replay subsystem. This event corresponds
> to execution of several instructions and used to synchronize input events
> in the replay phase.
> 
> Signed-off-by: Pavel Dovgalyuk <pavel.dovgaluk@ispras.ru>
> ---
>  replay/replay-internal.c |   14 ++++++++++++++
>  replay/replay-internal.h |   18 ++++++++++++++++++
>  replay/replay.c          |   45 +++++++++++++++++++++++++++++++++++++++++++++
>  replay/replay.h          |    7 +++++++
>  4 files changed, 84 insertions(+), 0 deletions(-)
> 
> diff --git a/replay/replay-internal.c b/replay/replay-internal.c
> index 429b13c..83a53bd 100755
> --- a/replay/replay-internal.c
> +++ b/replay/replay-internal.c
> @@ -10,6 +10,7 @@
>   */
>  
>  #include "qemu-common.h"
> +#include "replay.h"
>  #include "replay-internal.h"
>  
>  volatile unsigned int replay_data_kind = -1;
> @@ -139,3 +140,16 @@ void replay_fetch_data_kind(void)
>          }
>      }
>  }
> +
> +/*! Saves cached instructions. */
> +void replay_save_instructions(void)
> +{
> +    if (replay_file && replay_mode == REPLAY_MODE_RECORD) {
> +        int diff = (int)(replay_get_current_step() - replay_state.current_step);
> +        if (first_cpu != NULL && diff > 0) {
> +            replay_put_event(EVENT_INSTRUCTION);
> +            replay_put_dword(diff);
> +            replay_state.current_step += diff;
> +        }
> +    }
> +}
> diff --git a/replay/replay-internal.h b/replay/replay-internal.h
> index 927f7c7..582b44c 100755
> --- a/replay/replay-internal.h
> +++ b/replay/replay-internal.h
> @@ -14,6 +14,17 @@
>  
>  #include <stdio.h>
>  
> +/* for instruction event */
> +#define EVENT_INSTRUCTION           32
> +
> +typedef struct ReplayState {
> +    /*! Current step - number of processed instructions and timer events. */
> +    uint64_t current_step;
> +    /*! Number of instructions to be executed before other events happen. */
> +    int instructions_count;
> +} ReplayState;
> +extern ReplayState replay_state;
> +
>  extern volatile unsigned int replay_data_kind;
>  extern volatile unsigned int replay_has_unread_data;
>  
> @@ -47,4 +58,11 @@ void replay_save_instructions(void);
>      Terminates the program in case of error. */
>  void validate_data_kind(int kind);
>  
> +/*! Skips async events until some sync event will be found. */
> +bool skip_async_events(int stop_event);
> +/*! Skips async events invocations from the input,
> +    until required data kind is found. If the requested data is not found
> +    reports an error and stops the execution. */
> +void skip_async_events_until(unsigned int kind);
> +
>  #endif
> diff --git a/replay/replay.c b/replay/replay.c
> index ac976b2..93d3d7e 100755
> --- a/replay/replay.c
> +++ b/replay/replay.c
> @@ -9,7 +9,10 @@
>   *
>   */
>  
> +#include "qemu-common.h"
>  #include "replay.h"
> +#include "replay-internal.h"
> +#include "qemu/timer.h"
>  
>  ReplayMode replay_mode = REPLAY_MODE_NONE;
>  /*! Stores current submode for PLAY mode */
> @@ -18,8 +21,50 @@ ReplaySubmode play_submode = REPLAY_SUBMODE_UNKNOWN;
>  /* Suffix for the disk images filenames */
>  char *replay_image_suffix;
>  
> +ReplayState replay_state;
>  
>  ReplaySubmode replay_get_play_submode(void)
>  {
>      return play_submode;
>  }
> +
> +bool skip_async_events(int stop_event)
> +{
> +    /* nothing to skip - not all instructions used */
> +    if (replay_state.instructions_count != 0
> +        && replay_has_unread_data) {
> +        return stop_event == EVENT_INSTRUCTION;
> +    }
> +
> +    bool res = false;

The variable declaration should be placed head of the function.

Regards,
-Gonglei

> +    while (true) {
> +        replay_fetch_data_kind();
> +        if (stop_event == replay_data_kind) {
> +            res = true;
> +        }
> +        switch (replay_data_kind) {
> +        case EVENT_INSTRUCTION:
> +            replay_state.instructions_count = replay_get_dword();
> +            return res;
> +        default:
> +            /* clock, time_t, checkpoint and other events */
> +            return res;
> +        }
> +    }
> +
> +    return res;
> +}
> +
> +void skip_async_events_until(unsigned int kind)
> +{
> +    if (!skip_async_events(kind)) {
> +        fprintf(stderr, "%"PRId64": Read data kind %d instead of expected %d\n",
> +            replay_get_current_step(), replay_data_kind, kind);
> +        exit(1);
> +    }
> +}
> +
> +uint64_t replay_get_current_step(void)
> +{
> +    return cpu_get_icount_raw();
> +}
> diff --git a/replay/replay.h b/replay/replay.h
> index 51a18fe..e40daf5 100755
> --- a/replay/replay.h
> +++ b/replay/replay.h
> @@ -12,6 +12,8 @@
>   *
>   */
>  
> +#include <stdbool.h>
> +#include <stdint.h>
>  #include "qapi-types.h"
>  
>  extern ReplayMode replay_mode;
> @@ -20,4 +22,9 @@ extern char *replay_image_suffix;
>  /*! Returns replay play submode */
>  ReplaySubmode replay_get_play_submode(void);
>  
> +/* Processing the instructions */
> +
> +/*! Returns number of executed instructions. */
> +uint64_t replay_get_current_step(void);
> +
>  #endif
> 
>