Pieces getting stuck

[Delian]

A few facts:

-Windows XP (somewhat tweaked)

-No firewall

-No router

-No conflicting programs

To present the issue more clearly, let me post an image.

As seen, pieces are getting stuck at high % of finished blocks. This, however, does not directly affect the actual speed or the ability to finish the torrent. When the torrent is about to finish, the remaining blocks of this stuck pieces turn greenish in color and then finish non-the-less (what exactly is this behaviour?). However, this is still annoying, because:

-Priority has no effect on these pieces and a lot of such pieces will usually not finish until the torrent is almost complete (and thus I won't be able to open their files until then).

-It's harder to complete the first piece and start sharing.

-Having less finished pieces makes my client less "interesting" for other clients and so less efficient.

My guess would be, that connections bound to the troublesome pieces somehow remain open, preventing other connections from being established and finishing the piece.

When I tried µTorrent on other machines, I didn't get the same problem. Also, the problem is the same for all versions of µTorrent. So in the end, this issue may not be due to µTorrent itself, but I'm still trying to find someone, who would be kind enough to help me troubleshoot the program or windows, to get to the bottom of this matter.

Thanks.

[Switeck]

Try putting uTorrent into seed-only mode using Scheduler.

I've heard currently started chunks or pieces may still finish while in that mode but new pieces will not start.

It's only a workaround...and I'm not even sure it will help.

...But it's the best I can suggest at this time.

Another thought:

Changing the upload slots to a lower number will "encourage" faster peers to upload more to you.

If you can raise upload speed slightly as well, the boost should be noticeable.

[DreadWingKnight]

Reducing the number of peer connections may help as well, as you'll be requesting pieces from fewer peers, there will be fewer active pieces in the queue.

[Delian]

@Switeck

Thanks for suggestion. But unfortunately it doesn't work. The pieces/blocks don't get finished like when the torrent's finishing. Also, new blocks don't start, so no piece gets completed.

@DreadWingKnight

Sorry, but I have 20/20Mbit connection, and I need a lot of connections and slots so the bandwidth gets utilized. I even have 64 max half-open connections (100 for the windows).

[DreadWingKnight]

High halfopen connection limits are useless after the first minute of a torrent's start state.

Being reachable cuts that time down to about 20 seconds.

Having high halfopen connection limits set in your programs causes more problems down the road when (not if) microsoft un-patches.

[Delian]

I found that higher number of half-open connections increases performance for me quite a bit (on torrents with high number of peers). But anyway..

Even when I had default number of half-open connections, I got this same issue, so I doubt that's the case.

[Switeck]

Is your upload bandwidth anywhere near fully utilized?

I'd expect you can probably upload over 2 MB/second in uTorrent.

[Delian]

Yes, I can utilize 2.5MB/s without problems.

[Switeck]

If you're needing a high half open connection rate, are you ALSO disconnecting from peers/seeds extremely rapidly?

(That might be hostile ISP behavior were that the case!)

[Delian]

Thank you for your time.

I'm not sure, but I don't think that's the case either. From what I can tell, I can keep connections to peers, without them disconnecting. In most cases even for the whole duration of the download. Also, I'm fairly certain my ISP isn't hostile / limiting / blocking anything in any way. As I said, I don't get this problem on other machines, and they're using the same ISP.

And even if I was disconnecting, wouldn't that have the exact opposite effect on this issue? The blocks wouldn't get stuck and other peers could connect to finish them.

[Switeck]

I can't understand why, but it almost sounds like your connection is getting snubbed a lot by other peers.

[Delian]

Umm. Wouldn't it get snubbed only if I had a lack of slots and would refuse to send them? And wouldn't I get low download speeds beacuse of it? And from what I can tell, with 30 slots per torrent, I don't think that's happening.

[Switeck]

The other peers BitTorrent client settings may be the cause then.

They upload to you for awhile and stall...probably because they are now uploading to someone else.

If they have 100+ connections on the same torrent and try to upload to each of them first, they may take a VERY long time to get back to you!

This would look a lot like they're snubbing you.

[Delian]

That seems possible.

Is there a way to counter such behaviour? Like when the torrent's finishing, it seems to disconnect everyone but a few fastest peers to finish the remaining blocks?

Perhaps this could be turned into a suggestion for future versions. If any block is taking too long to finish, disconnect the culprit and let someone else finish it? Perhaps even let users specify the timeout for blocks.