events.txt

来自「disksim是一个非常优秀的磁盘仿真工具」· 文本 代码 · 共 218 行

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IO_ACCESS_ARRIVE

This is the first step.
Initializes the reqinfo structure.
Re-schedules the event as s DEVICE_OVERHEAD_COMPLETE at simtime + overhead.

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DEVICE_OVERHEAD_COMPLETE

Overhead is complete.
Adds request to the sled's ioqueue.

If WRITE
   Schedule a MEMS_BUS_INITIATE event at the current time.
   Set bus_pending in the current request's mems_reqinfo structure.
   
If READ
   If all of the blocks are already buffered
      Pull the request out of the sled's ioqueue.
      Set it as having completed the media transfer.
      Schedule a MEMS_BUS_INITIATE event at the current time.
      Set bus_pending in the current request's mems_reqinfo structure.
      Free the current event.
      Return.
   Else
      Call send_disconnect.

If this is a batched request, the batch is complete
   If WRITE
      Schedule a MEMS_BUS_INITIATE event at the current time
      Set bus_pending in the current request's mems_reqinfo structure.
   Else
      Call send_disconnect().

If the sled is MEMS_SLED_INACTIVE
   Schedule a new MEMS_SLED_SCHEDULE event at the current time plus
     startup_time_ms
   Set the sled as being MEMS_SLED_ACTIVE.
   Update the spinup/spindown statistics.
   Update the energy statistics.
Else if the sled is MEMS_SLED_IDLE
   Schedule a new MEMS_SLED_SCHEDULE event at the current time.
   Remove the sled->active_request from the intq. (WHY?)
   Set the sled->active_request to be NULL.
   Figure out where the sled is at this point in time after having
     been idle and update the sled's position.
   Update energy statistics.

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MEMS_SLED_SCHEDULE

If sled is idle and the inactive_delay has passed
   Set sled->lastreq_comptime to be the current time.
   Set the sled to the center position.
   Set the sled as inactive.
   Free the current event.
   Update the spinup/spindown statistics.
   Return.
Else if the sled is idle but the inactive_delay has NOT passed
     Set the sled as being active.
     Remove the active_request from the intq (WHY?).
     Set the sled->active_request to be NULL.

If there is no active_request
   Set sled->active_request to the next request from the sled's
     ioqueue.
   If that's not NULL
      If there is more than one request in this batch
	 Call mems_update_reqinfo().
      Make a copy of the active_request event since it gets passed
         around as the request is serviced.
      Throw out old prefetch info.

If there is an active_request after all of that
   Update each extent with the next blocks that should be accessed.
   
Else
   There's nothing to do.
   If inactive_delay has NOT passed
      Set lastreq_comptime to the current time.
      Set the sled as being IDLE.
      Keep a pointer to this event "just in case".
      Re-schedule this event as a MEMS_SLED_SCHEDULE at inactive_delay_ms
        in the future.
   Else if inactive_delay has passed
	Set lastreq_comptime to the current time.
	Set the sled at the centermost position.
	Set the sled as INACTIVE.
	Free the current event.
	Update spinup/spindown statistics.
	Return.

Schedule this event as a MEMS_SLED_SEEK.

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MEMS_SLED_SEEK

Find the seek time to both the up and down positions, and choose the
  direction with the shortest seek time.
Re-schedule this event as a MEMS_SLED_SERVO.
Update the sled's position.
Update energy statistics.

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MEMS_SLED_SERVO

Calculate the time to access the servo bits.
If there is an active request
   Re-schedule this event as a MEMS_SLED_DATA.
Else
   Re-schedule this event as a MEMS_SLED_SCHEDULE.

If there is an active request and it's a WRITE
   If there is no data to be written yet in any of the extents
      Re-schedule this event as a MEMS_SLED_SCHEDULE.

Update the sled's position.
Update energy statistics.

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MEMS_SLED_DATA

Calculate the time to access the sector.
Re-schedule this event as a MEMS_SLED_UPDATE.
Update the sled's position.
Update energy statistics.

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MEMS_SLED_UPDATE

If there is an active_request
   Go through each extent and update completed_block_media.
      If the extent is for a READ and the bus is not already pending
	 Schedule a new MEMS_BUS_INITIATE event.
	 Set bus_pending.
      If the extent's media transfer is complete
	 If the bus transfer is complete
	    Remove the extent from the extent list.
	    Update the batch stats.
	    Call mems_request_complete() for the extent's request.
	    Free the request.
	    Free the extent.
   If all of the media transfer is done
      Free the active_request.
      Set lastreq_comptime.
      Set active_request to NULL.

Re-schedule this event as a MEMS_SLED_SCHEDULE.
	    
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IO_INTERRUPT_COMPLETE

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MEMS_BUS_INITIATE

Choose an extent to start transferring over the bus.
If there isn't already a request on the device's dataxfer_req, set
   this one as the one.
   Call send_reconnect().
Else
   Insert this event at the end of the dataxfer_queue.

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MEMS_BUS_TRANSFER

Re-schedule this event as a MEMS_BUS_UPDATE.
Call device_get_blktranstime() to get the transfer time.

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MEMS_BUS_UPDATE

Update the last block transfered in the bus_extent.

If the bus_extent's bus transfer is complete
   If media access is also complete
      Remove extent from extent list.
      Call mems_request_complete().
      Free bus_extent->request.
      Free bus_extent.
   Check for more extents that need bus transfers.
   If there are NO more extents that need bus transfer
      Set dataxfer_req to NULL.
      If the request was a READ and there are no more extents
	 Free the reqinfo structure.
   Else
      Set the bus_extent to be the new extent pointer.
Else if the request is a read but the media hasn't finished yet
   Set dataxfer_req to be NULL.
   Set bus_pending to be FALSE.

If there is no dataxfer_req
   If there is a request waiting in the dataxfer_queue
      Pull off the first request.
      Call send_reconnect().
   Else
      Call send_disconnect().
   Free the current event.
   Return.

Re-schedule this event as a MEMS_BUS_TRANSFER.

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IO_QLEN_MAXCHECK

Some crappy function that only gets called once.