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Éder F. Zulian
2018-07-12 08:30:51 +02:00
parent 10723f588f
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README.md
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@@ -884,10 +884,10 @@ granular refresh (RGR).
**Pull-In Refresh** **Pull-In Refresh**
A Pull-In is started when there are no pending requests in the buffer, meaning A pull-in starts when there are no pending requests in the memory controller's
the memory is in an idle state. Therefore, in order to prepare for possible buffer, meaning the memory is in idle state. Therefore, in order to prepare
accesses that might happen in the future, a burst of REF commands is for possible accesses that might happen in the future, a burst of REF commands
initiated. If, at any point, requests start coming in, the burst is is initiated. If, at any point, requests start coming in, the burst is
interrupted, meaning that the maximum amount of time, considering the worst interrupted, meaning that the maximum amount of time, considering the worst
case scenario (a request arrives at the same time a REF was issued), is a case scenario (a request arrives at the same time a REF was issued), is a
refresh cycle time (tRFC). The advantage of pulling-in refreshes is that they refresh cycle time (tRFC). The advantage of pulling-in refreshes is that they
@@ -896,14 +896,16 @@ efficient accesses to the memory.
**Postpone Refresh** **Postpone Refresh**
Similarly, the decision to postpone a refresh is done if there are pending Similarly, the decision to postpone a refresh is done if by the time of a
requests on the buffer. Buffered requests may generate row-hits, so postponing refresh due there are pending requests on the buffer. Buffered requests may
refreshes may be beneficial for it avoids breaking row-hit sequences what generate row-hits, so postponing refreshes may be beneficial for it avoids
reduces the number of commands (e.g., ACT, PRE) to carry out the memory breaking row-hit sequences what reduces the number of commands (e.g., ACT,
accesses. If the memory enters an idle state, a burst is issued for the same PRE) to carry out the memory accesses and improves the overall system
number of REF commands that were postponed. When the maximum allowed preformance (accesses that are row-hits consume less time). If the memory is
number of postponed refreshes is reached a burst is issued in the next idle, in the next refresh interval (tREFI) a burst is issued for the same
refresh interval despite the memory state (busy or idle). number of REF commands postponed plus the actual refresh for that tREFI. When
the maximum number of postponed refreshes is reached a burst is issued in the
next tREFI despite the memory state (busy or idle).
**The Flexible Refresh FSM** **The Flexible Refresh FSM**