sick13 Posted October 24, 2005 Report Share Posted October 24, 2005 i think that speed fluctuation issue when d/l. For example the majority of my d/l varies by up too 25% with this client, where the same file with BC or AZ stays stable. If this issue could be solved it would be my first choice for uTorrent Link to comment Share on other sites More sharing options...
sethg Posted October 24, 2005 Report Share Posted October 24, 2005 This is pretty hard to track down, as it has a lot to do with the particular torrent you are downloading. One thing to make sure is that you have your maximum download and upload speed set to less than the actual bandwidth of your connection. You want the BT client to limit your bandwidth, not your ISP. A good place to start is at 75% of your connection bandwidth in each direction, and you can fool around with it from there. Link to comment Share on other sites More sharing options...
sick13 Posted October 25, 2005 Author Report Share Posted October 25, 2005 75% you say....well i tryed that last night and nothing....even diferent torrents nothingi think it is a speed fluctuation other Torrent clients are more or less stableThx for the reply! Link to comment Share on other sites More sharing options...
sethg Posted October 25, 2005 Report Share Posted October 25, 2005 Could you possibly post the number of connected seeds/peers and total seeds/peers in one of the torrents where you see this problem? I ask because I notice that uTorrent appears to ramp up the upload/download speed slower than other clients when optimistically unchoking a peer. This would result in larger fluctuations in download bandwidth, particularly in small or insuffficiently seeded swarms.You might be able to mask this effect somewhat by changing the maximum number of upload slots from four to, say, six. This might decrease your total download speed, but if I'm right, it will also decrease the variability you are seeing. Thanks for your help debugging this client. Link to comment Share on other sites More sharing options...
sick13 Posted October 25, 2005 Author Report Share Posted October 25, 2005 ok here it goesafter leaving Utorrent to download for about 20min'stotal Seeds/Peers is 32/56 and connected S/P is 9/17 {but this is not exact as it goes up and down } and i tried disabeling all internet activity from my PC that can cause a download or Upload so just leaving uTorrent to download/Upoload i still see speed fluctuation even tried on my friends pc with same and diferent torrents all the settings on uTorrent are defaultGreetz Link to comment Share on other sites More sharing options...
sethg Posted October 26, 2005 Report Share Posted October 26, 2005 That's a reasonable size swarm. You are connected to nine seeders, of which some are uploading data to you and some not. Out of the seventeen connected peers, only four are uploading data to you at any given time, with a fifth peer being "tested". Once every thirty seconds or so, uTorrent (and all other BT clients) will pick a random peer and optimistically unchoke them as a test. You upload some data to them and request that they share data with you. At the end of the thirty seconds, you select the four peers that send you the most data and discard the fifth. You then select another peer at random for testing and the cycle repeats.Because it takes some seconds before we can ramp up sending data to the fifth peer that we are testing, and it takes further time for them to send data back to us, the download rate will naturally go up and down as we select which peers to keep and which new one to test. If the combined download rate of the seeders is much larger than the four peers, we will barely notice this fluctuation. However, if the peers account for as much or more of the download rate than the seeds, the fluctuation when we change peers will be larger. That is largely a function of the swarm, but the client can have some affect on this.Another factor that affects your download rate is how many of the seeders you are connected to are uploading data to you at any given time. Since the seeders each have a limited number of upload slots, they choose the peers who can accept the data at the highest rate, unless they are superseeding. If your maximum line download rate is lower than other peers in the swarm, they will tend to get more data than you from the seeds. Since seeders also periodically test new peers for upload rates, there is a natural fluctuation due to that, as well.One thing that I have noticed with uTorrent is that it takes a bit longer to ramp up the data upload to the newly chosen fifth peer than some other clients. It also appears that it takes longer for the incoming data from that peer to ramp up than with some other clients. This can result in more fluctuation in the total download rate from the peers. While I can't tell why this is the case, one thing you can do to lessen the fluctuation is to increase the number of upload slots per torrent from four to six. This means there will be six peers exchanging data with you at any given time while you are testing a seventh. Your upload rate to each of the peers will probably be less, assuming that you hit the upload limit that you set at approximately 75% of your bandwidth. This means the download rates from each peer will also probably be lower, but the peer being tested should account for a smaller fraction of the total download rate if there are six upload slots instead of four. Try that and let us know if it helps. Since the results depend a lot on the specific swarm, you probably should try a torrent using four upload slots, then change to six upload slots after things settle down to a steady state.I tried the above experiment on a swarm roughly the same size as the one you reported. I did see fluctuations of around +/-15% around the mean value of around 90kB/s with an upload rate of 51kB/s. Increasing the upload slots from four to six increased the average download bandwidth to around 105kB/s, but the fluctuations were approximately the same. Most of the download was from peers, not seeds. I then stopped the torrent, started up Azureus and continued from where I left off. While Azureus was able to achieve a download rate of around 130kB/s, it was clearly because it connected to roughly twice as many seeds and peers. The fluctuation around the mean download value was somewhat greater than with uTorrent, ranging from 100kB/s to 145kB/s, while the upload speed was the same. My line speed is 1.5Mib/512kb and my limits were set to 153kB/51kB in both clients.It is obviously critical how many seeds and peers we can connect with. If the line is asymmetrical, as in my case, the number of seeds is particularly important. That is one improvement we can look forward to when DHT is implemented.How do your results compare to mine? Link to comment Share on other sites More sharing options...
sethg Posted October 26, 2005 Report Share Posted October 26, 2005 Changing my down/up limits in Azureus to 140kB/41kB/s allowed both data rates to stabilize around the limits with only a couple of percent variation. I think the percentage of your maximum upload bandwidth that you use is very important. There are a lot of ISP's that don't gracefully handle pushing the upload limit and mine is apparently one of them. They almost all handle download limiting well, however Part of the issue here is that my connection is ADSL. The transport service on that type of line is very similar to ATM, which has much smaller packet size than Ethernet. The inexpensive ADSL modem/router my ISP provides does not appear to do a good job of holding off the Ethernet side when the ATM side is overloaded. This would result in packets being dropped and retransmissions requested later.I suspect that if you experiment with the upload limit in this manner, you will get similar results with uTorrent. Link to comment Share on other sites More sharing options...
sick13 Posted October 26, 2005 Author Report Share Posted October 26, 2005 Thanx for the info....ill try experimenting People let's make uTorrent The Best & One&Only Link to comment Share on other sites More sharing options...
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