def __init__(self, hddname, sizekBs, sched, rambus):
Process.__init__(self, "Cache of %s"%(hddname))
self.sched = sched
self.rambus = rambus
self.openReqs = []
self.closedReqs = []
self.buffer = Buffer(self.name, sizekBs, 0)
self.size = sizekBs
self.flushNow = SimEvent(name="Flush Now")
self.flush = Flush(self)
class Cache(Process):
def __init__(self, hddname, sizekBs, sched, rambus):
Process.__init__(self, "Cache of %s"%(hddname))
self.sched = sched
self.rambus = rambus
self.openReqs = []
self.closedReqs = []
self.buffer = Buffer(self.name, sizekBs, 0)
self.size = sizekBs
self.flushNow = SimEvent(name="Flush Now")
self.flush = Flush(self)
def fillCache(self, waitInterval):
activate(self.flush, self.flush.flushCache())
while True:
# Attempts to get a new request from the scheduler's sorted list
# if it fails, the cache will wait waitInterval ms and try again.
try:
nextIO = self.sched.nextRequest()
except IndexError:
yield hold, self, waitInterval
continue
# Once the cache has found a request to be processed by the HDD,
# it waits for the cache to have enough space for the data.
print "IO being added to HDD Cache", nextIO
while nextIO.size > self.buffer.freeSpace():
print "not enough rooom for nextIO, %i items to flush"%len(self.closedReqs)
if len(self.closedReqs) > 2:
self.flushNow.signal()
yield waitevent, self, self.flush.flushComplete
else:
yield hold, self, waitInterval
# Once enough bytes free up, the cache marks that the new request's
# data size is being used in the cache and adds the request to
# the cache's FIFO list of pending requests. If the request is a
# write request, it is marked as complete.
yield put, self, self.buffer, nextIO.size
self.openReqs.append(nextIO)
if nextIO.write:
self.closedReqs.append(nextIO)
