mem: Comment clean-up for the snoop filter
Merely fixing up some style issues and adding more comments.
This commit is contained in:
parent
7d4e89d4e0
commit
5570aa9e9a
2 changed files with 54 additions and 39 deletions
|
@ -34,12 +34,12 @@
|
|||
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
*
|
||||
* Authors: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
|
||||
* Authors: Stephan Diestelhorst
|
||||
*/
|
||||
|
||||
/**
|
||||
* @file
|
||||
* Definition of a snoop filter.
|
||||
* Implementation of a snoop filter.
|
||||
*/
|
||||
|
||||
#include "base/misc.hh"
|
||||
|
|
|
@ -34,7 +34,7 @@
|
|||
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
|
||||
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
|
||||
*
|
||||
* Authors: Stephan Diestelhorst <stephan.diestelhorst@arm.com>
|
||||
* Authors: Stephan Diestelhorst
|
||||
*/
|
||||
|
||||
/**
|
||||
|
@ -96,8 +96,8 @@ class SnoopFilter : public SimObject {
|
|||
}
|
||||
|
||||
/**
|
||||
* Init a new snoop filter and tell it about all the
|
||||
* slave ports of the enclosing bus.
|
||||
* Init a new snoop filter and tell it about all the slave ports
|
||||
* of the enclosing bus.
|
||||
*
|
||||
* @param slave_ports Slave ports that the bus is attached to.
|
||||
*/
|
||||
|
@ -146,9 +146,10 @@ class SnoopFilter : public SimObject {
|
|||
void finishRequest(bool will_retry, const Packet* cpkt);
|
||||
|
||||
/**
|
||||
* Handle an incoming snoop from below (the master port). These can upgrade the
|
||||
* tracking logic and may also benefit from additional steering thanks to the
|
||||
* snoop filter.
|
||||
* Handle an incoming snoop from below (the master port). These
|
||||
* can upgrade the tracking logic and may also benefit from
|
||||
* additional steering thanks to the snoop filter.
|
||||
*
|
||||
* @param cpkt Pointer to const Packet containing the snoop.
|
||||
* @return Pair with a vector of SlavePorts that need snooping and a lookup
|
||||
* latency.
|
||||
|
@ -156,9 +157,9 @@ class SnoopFilter : public SimObject {
|
|||
std::pair<SnoopList, Cycles> lookupSnoop(const Packet* cpkt);
|
||||
|
||||
/**
|
||||
* Let the snoop filter see any snoop responses that turn into request responses
|
||||
* and indicate cache to cache transfers. These will update the corresponding
|
||||
* state in the filter.
|
||||
* Let the snoop filter see any snoop responses that turn into
|
||||
* request responses and indicate cache to cache transfers. These
|
||||
* will update the corresponding state in the filter.
|
||||
*
|
||||
* @param cpkt Pointer to const Packet holding the snoop response.
|
||||
* @param rsp_port SlavePort that sends the response.
|
||||
|
@ -169,28 +170,58 @@ class SnoopFilter : public SimObject {
|
|||
const SlavePort& req_port);
|
||||
|
||||
/**
|
||||
* Pass snoop responses that travel downward through the snoop filter and let
|
||||
* them update the snoop filter state. No additional routing happens.
|
||||
* Pass snoop responses that travel downward through the snoop
|
||||
* filter and let them update the snoop filter state. No
|
||||
* additional routing happens.
|
||||
*
|
||||
* @param cpkt Pointer to const Packet holding the snoop response.
|
||||
* @param rsp_port SlavePort that sends the response.
|
||||
* @param req_port MasterPort through which the response leaves this cluster.
|
||||
* @param req_port MasterPort through which the response is forwarded.
|
||||
*/
|
||||
void updateSnoopForward(const Packet *cpkt, const SlavePort& rsp_port,
|
||||
const MasterPort& req_port);
|
||||
|
||||
/**
|
||||
* Update the snoop filter with a response from below (outer / other cache,
|
||||
* or memory) and update the tracking information in the snoop filter.
|
||||
* Update the snoop filter with a response from below (outer /
|
||||
* other cache, or memory) and update the tracking information in
|
||||
* the snoop filter.
|
||||
*
|
||||
* @param cpkt Pointer to const Packet holding the snoop response.
|
||||
* @param slave_port SlavePort that made the original request and is the target
|
||||
* of this response.
|
||||
* @param slave_port SlavePort that made the original request and
|
||||
* is the target of this response.
|
||||
*/
|
||||
void updateResponse(const Packet *cpkt, const SlavePort& slave_port);
|
||||
|
||||
virtual void regStats();
|
||||
|
||||
protected:
|
||||
|
||||
/**
|
||||
* Simple factory methods for standard return values for lookupRequest
|
||||
* The underlying type for the bitmask we use for tracking. This
|
||||
* limits the number of snooping ports supported per crossbar. For
|
||||
* the moment it is an uint64_t to offer maximum
|
||||
* scalability. However, it is possible to use e.g. a uint16_t or
|
||||
* uint32_to slim down the footprint of the hash map (and
|
||||
* ultimately improve the simulation performance).
|
||||
*/
|
||||
typedef uint64_t SnoopMask;
|
||||
|
||||
/**
|
||||
* Per cache line item tracking a bitmask of SlavePorts who have an
|
||||
* outstanding request to this line (requested) or already share a
|
||||
* cache line with this address (holder).
|
||||
*/
|
||||
struct SnoopItem {
|
||||
SnoopMask requested;
|
||||
SnoopMask holder;
|
||||
};
|
||||
/**
|
||||
* HashMap of SnoopItems indexed by line address
|
||||
*/
|
||||
typedef m5::hash_map<Addr, SnoopItem> SnoopFilterCache;
|
||||
|
||||
/**
|
||||
* Simple factory methods for standard return values.
|
||||
*/
|
||||
std::pair<SnoopList, Cycles> snoopAll(Cycles latency) const
|
||||
{
|
||||
|
@ -207,24 +238,6 @@ class SnoopFilter : public SimObject {
|
|||
return std::make_pair(empty , latency);
|
||||
}
|
||||
|
||||
virtual void regStats();
|
||||
|
||||
protected:
|
||||
typedef uint64_t SnoopMask;
|
||||
/**
|
||||
* Per cache line item tracking a bitmask of SlavePorts who have an
|
||||
* outstanding request to this line (requested) or already share a cache line
|
||||
* with this address (holder).
|
||||
*/
|
||||
struct SnoopItem {
|
||||
SnoopMask requested;
|
||||
SnoopMask holder;
|
||||
};
|
||||
/**
|
||||
* HashMap of SnoopItems indexed by line address
|
||||
*/
|
||||
typedef m5::hash_map<Addr, SnoopItem> SnoopFilterCache;
|
||||
|
||||
/**
|
||||
* Convert a single port to a corresponding, one-hot bitmask
|
||||
* @param port SlavePort that should be converted.
|
||||
|
@ -244,6 +257,7 @@ class SnoopFilter : public SimObject {
|
|||
* Removes snoop filter items which have no requesters and no holders.
|
||||
*/
|
||||
void eraseIfNullEntry(SnoopFilterCache::iterator& sf_it);
|
||||
|
||||
/** Simple hash set of cached addresses. */
|
||||
SnoopFilterCache cachedLocations;
|
||||
/**
|
||||
|
@ -296,4 +310,5 @@ SnoopFilter::maskToPortList(SnoopMask port_mask) const
|
|||
res.push_back(p);
|
||||
return res;
|
||||
}
|
||||
|
||||
#endif // __MEM_SNOOP_FILTER_HH__
|
||||
|
|
Loading…
Reference in a new issue