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447 rivejä
17 KiB
447 rivejä
17 KiB
#! /usr/bin/env python
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import math
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import random
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from optparse import OptionParser
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# minimum unit of transfer to RAID
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BLOCKSIZE = 4096
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def convert(size):
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length = len(size)
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lastchar = size[length-1]
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if (lastchar == 'k') or (lastchar == 'K'):
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m = 1024
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nsize = int(size[0:length-1]) * m
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elif (lastchar == 'm') or (lastchar == 'M'):
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m = 1024*1024
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nsize = int(size[0:length-1]) * m
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elif (lastchar == 'g') or (lastchar == 'G'):
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m = 1024*1024*1024
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nsize = int(size[0:length-1]) * m
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else:
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nsize = int(size)
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return nsize
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class disk:
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def __init__(self, seekTime=10, xferTime=0.1, queueLen=8):
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# these are both in milliseconds
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# seek is the time to seek (simple constant amount)
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# transfer is the time to read one block
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self.seekTime = seekTime
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self.xferTime = xferTime
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# length of scheduling queue
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self.queueLen = queueLen
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# current location: make it negative so that whatever
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# the first read is, it causes a seek
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self.currAddr = -10000
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# queue
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self.queue = []
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# disk geometry
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self.numTracks = 100
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self.blocksPerTrack = 100
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self.blocksPerDisk = self.numTracks * self.blocksPerTrack
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# stats
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self.countIO = 0
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self.countSeq = 0
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self.countNseq = 0
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self.countRand = 0
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self.utilTime = 0
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def stats(self):
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return (self.countIO, self.countSeq, self.countNseq, self.countRand, self.utilTime)
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def enqueue(self, addr):
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assert(addr < self.blocksPerDisk)
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self.countIO += 1
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# check if this is on the same track, or a different one
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currTrack = self.currAddr / self.numTracks
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newTrack = addr / self.numTracks
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# absolute diff
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diff = addr - self.currAddr
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# if on the same track...
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if currTrack == newTrack or diff < self.blocksPerTrack:
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if diff == 1:
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self.countSeq += 1
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else:
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self.countNseq += 1
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self.utilTime += (diff * self.xferTime)
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else:
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self.countRand += 1
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self.utilTime += (self.seekTime + self.xferTime)
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self.currAddr = addr
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def go(self):
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return self.utilTime
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class raid:
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def __init__(self, chunkSize='4k', numDisks=4, level=0, timing=False, reverse=False, solve=False, raid5type='LS'):
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chunkSize = int(convert(chunkSize))
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self.chunkSize = chunkSize / BLOCKSIZE
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self.numDisks = numDisks
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self.raidLevel = level
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self.timing = timing
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self.reverse = reverse
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self.solve = solve
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self.raid5type = raid5type
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if (chunkSize % BLOCKSIZE) != 0:
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print 'chunksize (%d) must be multiple of blocksize (%d): %d' % (chunkSize, BLOCKSIZE, self.chunkSize % BLOCKSIZE)
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exit(1)
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if self.raidLevel == 1 and numDisks % 2 != 0:
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print 'raid1: disks (%d) must be a multiple of two' % numDisks
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exit(1)
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if self.raidLevel == 4:
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self.blocksInStripe = (self.numDisks - 1) * self.chunkSize
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self.pdisk = self.numDisks - 1
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if self.raidLevel == 5:
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self.blocksInStripe = (self.numDisks - 1) * self.chunkSize
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self.pdisk = -1
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self.disks = []
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for i in range(self.numDisks):
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self.disks.append(disk())
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# print per-disk stats
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def stats(self, totalTime):
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for d in range(self.numDisks):
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s = self.disks[d].stats()
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if s[4] == totalTime:
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print 'disk:%d busy: %.2f I/Os: %5d (sequential:%d nearly:%d random:%d)' % (d, (100.0*float(s[4])/totalTime), s[0], s[1], s[2], s[3])
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elif s[4] == 0:
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print 'disk:%d busy: %.2f I/Os: %5d (sequential:%d nearly:%d random:%d)' % (d, (100.0*float(s[4])/totalTime), s[0], s[1], s[2], s[3])
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else:
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print 'disk:%d busy: %.2f I/Os: %5d (sequential:%d nearly:%d random:%d)' % (d, (100.0*float(s[4])/totalTime), s[0], s[1], s[2], s[3])
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# global enqueue function
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def enqueue(self, addr, size, isWrite):
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# should we print out the logical operation?
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if self.timing == False:
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if self.solve or self.reverse==False:
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if isWrite:
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print 'LOGICAL WRITE to addr:%d size:%d' % (addr, size * BLOCKSIZE)
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else:
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print 'LOGICAL READ from addr:%d size:%d' % (addr, size * BLOCKSIZE)
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if self.solve == False:
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print ' Physical reads/writes?\n'
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else:
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print 'LOGICAL OPERATION is ?'
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# should we print out the physical operations?
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if self.timing == False and (self.solve or self.reverse==True):
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self.printPhysical = True
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else:
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self.printPhysical = False
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if self.raidLevel == 0:
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self.enqueue0(addr, size, isWrite)
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elif self.raidLevel == 1:
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self.enqueue1(addr, size, isWrite)
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elif self.raidLevel == 4 or self.raidLevel == 5:
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self.enqueue45(addr, size, isWrite)
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# process disk workloads one at a time, returning final completion time
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def go(self):
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tmax = 0
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for d in range(self.numDisks):
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# print '**** disk ****', d
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t = self.disks[d].go()
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if t > tmax:
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tmax = t
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return tmax
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# helper functions
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def doSingleRead(self, disk, off, doNewline=False):
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if self.printPhysical:
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print ' read [disk %d, offset %d] ' % (disk, off),
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if doNewline:
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print ''
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self.disks[disk].enqueue(off)
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def doSingleWrite(self, disk, off, doNewline=False):
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if self.printPhysical:
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print ' write [disk %d, offset %d] ' % (disk, off),
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if doNewline:
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print ''
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self.disks[disk].enqueue(off)
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#
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# mapping for RAID 0 (striping)
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#
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def bmap0(self, bnum):
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cnum = bnum / self.chunkSize
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coff = bnum % self.chunkSize
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return (cnum % self.numDisks, (cnum / self.numDisks) * self.chunkSize + coff)
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def enqueue0(self, addr, size, isWrite):
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# can ignore isWrite, as I/O pattern is the same for striping
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for b in range(addr, addr+size):
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(disk, off) = self.bmap0(b)
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if isWrite:
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self.doSingleWrite(disk, off, True)
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else:
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self.doSingleRead(disk, off, True)
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if self.timing == False and self.printPhysical:
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print ''
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#
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# mapping for RAID 1 (mirroring)
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#
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def bmap1(self, bnum):
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cnum = bnum / self.chunkSize
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coff = bnum % self.chunkSize
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disk = 2 * (cnum % (self.numDisks / 2))
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return (disk, disk + 1, (cnum / (self.numDisks / 2)) * self.chunkSize + coff)
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def enqueue1(self, addr, size, isWrite):
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for b in range(addr, addr+size):
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(disk1, disk2, off) = self.bmap1(b)
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# print 'enqueue:', addr, size, '-->', m
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if isWrite:
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self.doSingleWrite(disk1, off, False)
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self.doSingleWrite(disk2, off, True)
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else:
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# the raid-1 read balancing algorithm is here;
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# could be something more intelligent --
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# instead, it is just based on the disk offset
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# to produce something easily reproducible
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if off % 2 == 0:
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self.doSingleRead(disk1, off, True)
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else:
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self.doSingleRead(disk2, off, True)
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if self.timing == False and self.printPhysical:
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print ''
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#
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# mapping for RAID 4 (parity disk)
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#
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# assumes (for now) that there is just one parity disk
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#
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def bmap4(self, bnum):
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cnum = bnum / self.chunkSize
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coff = bnum % self.chunkSize
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return (cnum % (self.numDisks - 1), (cnum / (self.numDisks - 1)) * self.chunkSize + coff)
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def pmap4(self, snum):
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return self.pdisk
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#
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# mapping for RAID 5 (rotated parity)
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#
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def __bmap5(self, bnum):
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cnum = bnum / self.chunkSize
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coff = bnum % self.chunkSize
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ddsk = cnum / (self.numDisks - 1)
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doff = (ddsk * self.chunkSize) + coff
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disk = cnum % (self.numDisks - 1)
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col = (ddsk % self.numDisks)
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pdsk = (self.numDisks - 1) - col
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# supports left-asymmetric and left-symmetric layouts
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if self.raid5type == 'LA':
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if disk >= pdisk:
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disk += 1
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elif self.raid5type == 'LS':
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disk = (disk - col) % (self.numDisks)
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else:
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print 'error: no such RAID scheme'
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exit(1)
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assert(disk != pdsk)
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return (disk, pdsk, doff)
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# yes this is lame (redundant call to __bmap5 is serious programmer laziness)
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def bmap5(self, bnum):
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(disk, pdisk, off) = self.__bmap5(bnum)
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return (disk, off)
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# this too is lame (redundant call to __bmap5 is serious programmer laziness)
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def pmap5(self, snum):
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(disk, pdisk, off) = self.__bmap5(snum * self.blocksInStripe)
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return pdisk
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# RAID 4/5 helper routine to write out some blocks in a stripe
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def doPartialWrite(self, stripe, begin, end, bmap, pmap):
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numWrites = end - begin
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pdisk = pmap(stripe)
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if (numWrites + 1) <= (self.blocksInStripe - numWrites):
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# SUBTRACTIVE PARITY
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# print 'SUBTRACTIVE'
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offList = []
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for voff in range(begin, end):
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(disk, off) = bmap(voff)
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self.doSingleRead(disk, off)
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if off not in offList:
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offList.append(off)
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for i in range(len(offList)):
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self.doSingleRead(pdisk, offList[i], i == (len(offList) - 1))
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else:
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# ADDITIVE PARITY
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# print 'ADDITIVE'
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stripeBegin = stripe * self.blocksInStripe
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stripeEnd = stripeBegin + self.blocksInStripe
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for voff in range(stripeBegin, begin):
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(disk, off) = bmap(voff)
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self.doSingleRead(disk, off, (voff == (begin - 1)) and (end == stripeEnd))
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for voff in range(end, stripeEnd):
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(disk, off) = bmap(voff)
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self.doSingleRead(disk, off, voff == (stripeEnd - 1))
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# WRITES: same for additive or subtractive parity
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offList = []
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for voff in range(begin, end):
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(disk, off) = bmap(voff)
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self.doSingleWrite(disk, off)
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if off not in offList:
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offList.append(off)
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for i in range(len(offList)):
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self.doSingleWrite(pdisk, offList[i], i == (len(offList) - 1))
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# RAID 4/5 enqueue routine
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def enqueue45(self, addr, size, isWrite):
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if self.raidLevel == 4:
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(bmap, pmap) = (self.bmap4, self.pmap4)
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elif self.raidLevel == 5:
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(bmap, pmap) = (self.bmap5, self.pmap5)
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if isWrite == False:
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for b in range(addr, addr+size):
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(disk, off) = bmap(b)
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self.doSingleRead(disk, off)
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else:
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# process the write request, one stripe at a time
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initStripe = (addr) / self.blocksInStripe
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finalStripe = (addr + size - 1) / self.blocksInStripe
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left = size
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begin = addr
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for stripe in range(initStripe, finalStripe + 1):
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endOfStripe = (stripe * self.blocksInStripe) + self.blocksInStripe
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if left >= self.blocksInStripe:
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end = begin + self.blocksInStripe
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else:
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end = begin + left
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if end >= endOfStripe:
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end = endOfStripe
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self.doPartialWrite(stripe, begin, end, bmap, pmap)
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left -= (end - begin)
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begin = end
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# for all cases, print this for pretty-ness in mapping mode
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if self.timing == False and self.printPhysical:
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print ''
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#
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# main program
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#
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parser = OptionParser()
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parser.add_option('-s', '--seed', default=0, help='the random seed', action='store', type='int', dest='seed')
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parser.add_option('-D', '--numDisks', default=4, help='number of disks in RAID', action='store', type='int', dest='numDisks')
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parser.add_option('-C', '--chunkSize', default='4k', help='chunk size of the RAID', action='store', type='string', dest='chunkSize')
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parser.add_option('-n', '--numRequests', default=10, help='number of requests to simulate', action='store', type='int', dest='numRequests')
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parser.add_option('-S', '--reqSize', default='4k', help='size of requests', action='store', type='string', dest='size')
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parser.add_option('-W', '--workload', default='rand', help='either "rand" or "seq" workloads', action='store', type='string', dest='workload')
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parser.add_option('-w', '--writeFrac', default=0, help='write fraction (100->all writes, 0->all reads)', action='store', type='int', dest='writeFrac')
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parser.add_option('-R', '--randRange', default=10000, help='range of requests (when using "rand" workload)', action='store', type='int', dest='range')
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parser.add_option('-L', '--level', default=0, help='RAID level (0, 1, 4, 5)', action='store', type='int', dest='level')
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parser.add_option('-5', '--raid5', default='LS', help='RAID-5 left-symmetric "LS" or left-asym "LA"', action='store', type='string', dest='raid5type')
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parser.add_option('-r', '--reverse', default=False, help='instead of showing logical ops, show physical', action='store_true', dest='reverse')
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parser.add_option('-t', '--timing', default=False, help='use timing mode, instead of mapping mode', action='store_true', dest='timing')
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parser.add_option('-c', '--compute', default=False, help='compute answers for me', action='store_true', dest='solve')
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(options, args) = parser.parse_args()
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print 'ARG blockSize', BLOCKSIZE
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print 'ARG seed', options.seed
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print 'ARG numDisks', options.numDisks
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print 'ARG chunkSize', options.chunkSize
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print 'ARG numRequests', options.numRequests
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print 'ARG reqSize', options.size
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print 'ARG workload', options.workload
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print 'ARG writeFrac', options.writeFrac
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print 'ARG randRange', options.range
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print 'ARG level', options.level
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print 'ARG raid5', options.raid5type
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print 'ARG reverse', options.reverse
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print 'ARG timing', options.timing
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print ''
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writeFrac = float(options.writeFrac) / 100.0
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assert(writeFrac >= 0.0 and writeFrac <= 1.0)
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random.seed(options.seed)
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size = convert(options.size)
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if size % BLOCKSIZE != 0:
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print 'error: request size (%d) must be a multiple of BLOCKSIZE (%d)' % (size, BLOCKSIZE)
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exit(1)
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size = size / BLOCKSIZE
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if options.workload == 'seq' or options.workload == 's' or options.workload == 'sequential':
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workloadIsSequential = True
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elif options.workload == 'rand' or options.workload == 'r' or options.workload == 'random':
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workloadIsSequential = False
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else:
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print 'error: workload must be either r/rand/random or s/seq/sequential'
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exit(1)
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assert(options.level == 0 or options.level == 1 or options.level == 4 or options.level == 5)
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if options.level != 0 and options.numDisks < 2:
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print 'RAID-4 and RAID-5 need more than 1 disk'
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exit(1)
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if options.level == 5 and options.raid5type != 'LA' and options.raid5type != 'LS':
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print 'Only two types of RAID-5 supported: left-asymmetric (LA) and left-symmetric (LS) (%s is not)' % options.raid5type
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exit(1)
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# instantiate RAID
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r = raid(chunkSize=options.chunkSize, numDisks=options.numDisks, level=options.level, timing=options.timing,
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reverse=options.reverse, solve=options.solve, raid5type=options.raid5type)
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# generate requests
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off = 0
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for i in range(options.numRequests):
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if workloadIsSequential == True:
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blk = off
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off += size
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else:
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blk = int(random.random() * options.range)
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if random.random() < writeFrac:
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r.enqueue(blk, size, True)
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else:
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r.enqueue(blk, size, False)
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# process requests
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t = r.go()
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# print out some final info, if needed
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if options.timing == False:
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print ''
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exit(0)
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if options.solve:
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print ''
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r.stats(t)
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print ''
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print 'STAT totalTime', t
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print ''
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else:
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print ''
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print 'Estimate how long the workload should take to complete.'
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print '- Roughly how many requests should each disk receive?'
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print '- How many requests are random, how many sequential?'
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print ''
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