extremely high cpu usage when adding a torrent

[feross]

Issue by vikstrous
Tuesday Jun 10, 2014 at 05:49 GMT
Originally opened as https://github.com/feross/bittorrent-client/issues/26

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Whenever I add a torrent (from a content hash) I get extremely high cpu usage for a while until it stops and streaming starts. It seems to have something to do with sha1 hashes and verifying pieces. This didn't happen in version 0.1.1. Has anyone else experienced this? If not, I'll try to get more details.

[feross]

Comment by feross
Tuesday Jun 10, 2014 at 06:10 GMT

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I've noticed this as well. I suspect it is caused by the code for verifying
incomplete pieces at startup (for resumable downloads). Unless the storage
is backed by disk (which vanilla bittorrent-client is not), we shouldn't
run this code.

Of course, this is only a guess.

On Monday, June 9, 2014, Viktor Stanchev notifications@github.com wrote:

Whenever I add a torrent (from a content hash) I get extremely high cpu
usage for a while until it stops and streaming starts. It seems to have
something to do with sha1 hashes and verifying pieces. This didn't happen
in version 0.1.1. Has anyone else experienced this? If not, I'll try to get
more details.

—
Reply to this email directly or view it on GitHub
https://github.com/feross/bittorrent-client/issues/26.

Feross | blog http://feross.org/ | webtorrent http://webtorrent.io/ |
studynotes http://www.apstudynotes.org/

[feross]

Comment by vikstrous
Tuesday Jun 10, 2014 at 14:43 GMT

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I confirmed that it's caused by https://github.com/feross/bittorrent-client/blob/master/lib/torrent.js#L560

However, setting {verify: false} in the BitTorrentClient constructor doesn't seem to bypass this verification.

[feross]

Comment by fisch0920
Thursday Jun 12, 2014 at 01:50 GMT

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Hmm, the verification code for non fs-storage should run in no time since all reads are shortcuts, but clearly there's an issue with the implementation.

[feross]

Closing out old issues. Feel free to comment or open a new issue if this still affects you.