/* PeerCheckTasks - TimerTask that checks for good/bad up/downloaders.
Copyright (C) 2003 Mark J. Wielaard
This file is part of Snark.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2, or (at your option)
any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software Foundation,
Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
package org.klomp.snark;
import java.util.ArrayList;
import java.util.Iterator;
import java.util.List;
import java.util.Random;
import java.util.TimerTask;
/**
* TimerTask that checks for good/bad up/downloader. Works together
* with the PeerCoordinator to select which Peers get (un)choked.
*/
class PeerCheckerTask extends TimerTask
{
private static final long KILOPERSECOND = 1024*(PeerCoordinator.CHECK_PERIOD/1000);
private final PeerCoordinator coordinator;
public I2PSnarkUtil _util;
PeerCheckerTask(I2PSnarkUtil util, PeerCoordinator coordinator)
{
_util = util;
this.coordinator = coordinator;
}
private Random random = new Random();
public void run()
{
synchronized(coordinator.peers)
{
Iterator it = coordinator.peers.iterator();
if ((!it.hasNext()) || coordinator.halted()) {
coordinator.peerCount = 0;
coordinator.interestedAndChoking = 0;
coordinator.setRateHistory(0, 0);
coordinator.uploaders = 0;
if (coordinator.halted())
cancel();
return;
}
// Calculate total uploading and worst downloader.
long worstdownload = Long.MAX_VALUE;
Peer worstDownloader = null;
int peers = 0;
int uploaders = 0;
int downloaders = 0;
int removedCount = 0;
long uploaded = 0;
long downloaded = 0;
// Keep track of peers we remove now,
// we will add them back to the end of the list.
List removed = new ArrayList();
int uploadLimit = coordinator.allowedUploaders();
boolean overBWLimit = coordinator.overUpBWLimit();
while (it.hasNext())
{
Peer peer = (Peer)it.next();
// Remove dying peers
if (!peer.isConnected())
{
it.remove();
coordinator.removePeerFromPieces(peer);
coordinator.peerCount = coordinator.peers.size();
continue;
}
peers++;
if (!peer.isChoking())
uploaders++;
if (!peer.isChoked() && peer.isInteresting())
downloaders++;
long upload = peer.getUploaded();
uploaded += upload;
long download = peer.getDownloaded();
downloaded += download;
peer.setRateHistory(upload, download);
peer.resetCounters();
_util.debug(peer + ":", Snark.DEBUG);
_util.debug(" ul: " + upload/KILOPERSECOND
+ " dl: " + download/KILOPERSECOND
+ " i: " + peer.isInterested()
+ " I: " + peer.isInteresting()
+ " c: " + peer.isChoking()
+ " C: " + peer.isChoked(),
Snark.DEBUG);
// Choke half of them rather than all so it isn't so drastic...
// unless this torrent is over the limit all by itself.
boolean overBWLimitChoke = upload > 0 &&
((overBWLimit && random.nextBoolean()) ||
(coordinator.overUpBWLimit(uploaded)));
// If we are at our max uploaders and we have lots of other
// interested peers try to make some room.
// (Note use of coordinator.uploaders)
if (((coordinator.uploaders == uploadLimit
&& coordinator.interestedAndChoking > 0)
|| coordinator.uploaders > uploadLimit
|| overBWLimitChoke)
&& !peer.isChoking())
{
// Check if it still wants pieces from us.
if (!peer.isInterested())
{
_util.debug("Choke uninterested peer: " + peer,
Snark.INFO);
peer.setChoking(true);
uploaders--;
coordinator.uploaders--;
// Put it at the back of the list
it.remove();
removed.add(peer);
}
else if (overBWLimitChoke)
{
_util.debug("BW limit (" + upload + "/" + uploaded + "), choke peer: " + peer,
Snark.INFO);
peer.setChoking(true);
uploaders--;
coordinator.uploaders--;
removedCount++;
// Put it at the back of the list for fairness, even though we won't be unchoking this time
it.remove();
removed.add(peer);
}
else if (peer.isInteresting() && peer.isChoked())
{
// If they are choking us make someone else a downloader
_util.debug("Choke choking peer: " + peer, Snark.DEBUG);
peer.setChoking(true);
uploaders--;
coordinator.uploaders--;
removedCount++;
// Put it at the back of the list
it.remove();
removed.add(peer);
}
else if (!peer.isInteresting() && !coordinator.completed())
{
// If they aren't interesting make someone else a downloader
_util.debug("Choke uninteresting peer: " + peer, Snark.DEBUG);
peer.setChoking(true);
uploaders--;
coordinator.uploaders--;
removedCount++;
// Put it at the back of the list
it.remove();
removed.add(peer);
}
else if (peer.isInteresting()
&& !peer.isChoked()
&& download == 0)
{
// We are downloading but didn't receive anything...
_util.debug("Choke downloader that doesn't deliver:"
+ peer, Snark.DEBUG);
peer.setChoking(true);
uploaders--;
coordinator.uploaders--;
removedCount++;
// Put it at the back of the list
it.remove();
removed.add(peer);
}
else if (peer.isInteresting() && !peer.isChoked() &&
download < worstdownload)
{
// Make sure download is good if we are uploading
worstdownload = download;
worstDownloader = peer;
}
else if (upload < worstdownload && coordinator.completed())
{
// Make sure upload is good if we are seeding
worstdownload = upload;
worstDownloader = peer;
}
}
peer.retransmitRequests();
peer.keepAlive();
}
// Resync actual uploaders value
// (can shift a bit by disconnecting peers)
coordinator.uploaders = uploaders;
// Remove the worst downloader if needed. (uploader if seeding)
if (((uploaders == uploadLimit
&& coordinator.interestedAndChoking > 0)
|| uploaders > uploadLimit)
&& worstDownloader != null)
{
_util.debug("Choke worst downloader: " + worstDownloader,
Snark.DEBUG);
worstDownloader.setChoking(true);
coordinator.uploaders--;
removedCount++;
// Put it at the back of the list
coordinator.peers.remove(worstDownloader);
coordinator.peerCount = coordinator.peers.size();
removed.add(worstDownloader);
}
// Optimistically unchoke a peer
if ((!overBWLimit) && !coordinator.overUpBWLimit(uploaded))
coordinator.unchokePeer();
// Put peers back at the end of the list that we removed earlier.
coordinator.peers.addAll(removed);
coordinator.peerCount = coordinator.peers.size();
coordinator.interestedAndChoking += removedCount;
// store the rates
coordinator.setRateHistory(uploaded, downloaded);
// close out unused files, but we don't need to do it every time
if (random.nextInt(4) == 0)
coordinator.getStorage().cleanRAFs();
}
}
}