š
Original date posted:2015-11-10
š Original message:On 10/11/2015 8:46 AM, Jeff Garzik via bitcoin-dev wrote:
> Comments:
>
> 1) cblock seems a reasonable way to extend the protocol. Further
> wrapping should probably be done at the stream level.
agreed.
>
> 2) zlib has crappy security track record.
>
Zlib had a bad buffer overflow bug but that was in 2005 and it got a lot
of press at the time. It's was fixed in version 1.2.3...we're on 1.2.8
now. I'm not aware of any other current issues with zlib. Do you have a
citation?
> 3) A fallback path to non-compressed is required, should compression
> fail or crash.
agreed.
>
> 4) Most blocks and transactions have runs of zeroes and/or highly
> common bit-patterns, which contributes to useful compression even at
> smaller sizes. Peter Ts's most recent numbers bear this out. zlib
> has a dictionary (32K?) which works well with repeated patterns such
> as those you see with concatenated runs of transactions.
>
> 5) LZO should provide much better compression, at a cost of CPU
> performance and using a less-reviewed, less-field-tested library.
I don't think LZO will give as good compression here but I will do some
benchmarking when I can.
>
>
>
>
>
> On Tue, Nov 10, 2015 at 11:30 AM, Tier Nolan via bitcoin-dev
> <bitcoin-dev at lists.linuxfoundation.org
> <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
>
>
>
> On Tue, Nov 10, 2015 at 4:11 PM, Peter Tschipper
> <peter.tschipper at gmail.com <mailto:peter.tschipper at gmail.com>> wrote:
>
> There are better ways of sending new blocks, that's certainly
> true but for sending historical blocks and seding transactions
> I don't think so. This PR is really designed to save
> bandwidth and not intended to be a huge performance
> improvement in terms of time spent sending.
>
>
> If the main point is for historical data, then sticking to just
> blocks is the best plan.
>
> Since small blocks don't compress well, you could define a
> "cblocks" message that handles multiple blocks (just concatenate
> the block messages as payload before compression).
>
> The sending peer could combine blocks so that each cblock is
> compressing at least 10kB of block data (or whatever is optimal).
> It is probably worth specifying a maximum size for network buffer
> reasons (either 1MB or 1 block maximum).
>
> Similarly, transactions could be combined together and compressed
> "ctxs". The inv messages could be modified so that you can
> request groups of 10-20 transactions. That would depend on how
> much of an improvement compressed transactions would represent.
>
> More generally, you could define a message which is a compressed
> message holder. That is probably to complex to be worth the
> effort though.
>
>
>
>>
>> On Tue, Nov 10, 2015 at 5:40 AM, Johnathan Corgan via
>> bitcoin-dev <bitcoin-dev at lists.linuxfoundation.org
>> <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
>>
>> On Mon, Nov 9, 2015 at 5:58 PM, gladoscc via bitcoin-dev
>> <bitcoin-dev at lists.linuxfoundation.org
>> <mailto:bitcoin-dev at lists.linuxfoundation.org>> wrote:
>>
>>
>> I think 25% bandwidth savings is certainly
>> considerable, especially for people running full
>> nodes in countries like Australia where internet
>> bandwidth is lower and there are data caps.
>>
>>
>> ā This reinforces the idea that such trade-off decisions
>> should be be local and negotiated between peers, not a
>> required feature of the network P2P.ā
>>
>>
>> --
>> Johnathan Corgan
>> Corgan Labs - SDR Training and Development Services
>> http://corganlabs.com
>>
>> _______________________________________________
>> bitcoin-dev mailing list
>> bitcoin-dev at lists.linuxfoundation.org
>> <mailto:bitcoin-dev at lists.linuxfoundation.org>
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>>
>>
>>
>>
>> _______________________________________________
>> bitcoin-dev mailing list
>> bitcoin-dev at lists.linuxfoundation.org
>> <mailto:bitcoin-dev at lists.linuxfoundation.org>
>> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org
> <mailto:bitcoin-dev at lists.linuxfoundation.org>
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
>
>
>
>
> _______________________________________________
> bitcoin-dev mailing list
> bitcoin-dev at lists.linuxfoundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev
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Peter Tschipper [ARCHIVE] /
npub14sā¦653tk
2023-06-07 17:44:24
in reply to nevent1qā¦v8zx
Author Public Key
npub14sxt5nq5l8hfvd7yfcmh8gwjqhtzcc72vz2lcwd2uw0xlllwdayqk653tkPublished at
2023-06-07 17:44:24Event JSON
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Original date posted:2015-11-10\nš Original message:On 10/11/2015 8:46 AM, Jeff Garzik via bitcoin-dev wrote:\n\u003e Comments:\n\u003e\n\u003e 1) cblock seems a reasonable way to extend the protocol. Further\n\u003e wrapping should probably be done at the stream level.\nagreed.\n\u003e\n\u003e 2) zlib has crappy security track record.\n\u003e\nZlib had a bad buffer overflow bug but that was in 2005 and it got a lot\nof press at the time. It's was fixed in version 1.2.3...we're on 1.2.8\nnow. I'm not aware of any other current issues with zlib. Do you have a\ncitation?\n\n\u003e 3) A fallback path to non-compressed is required, should compression\n\u003e fail or crash.\nagreed.\n\u003e\n\u003e 4) Most blocks and transactions have runs of zeroes and/or highly\n\u003e common bit-patterns, which contributes to useful compression even at\n\u003e smaller sizes. Peter Ts's most recent numbers bear this out. zlib\n\u003e has a dictionary (32K?) which works well with repeated patterns such\n\u003e as those you see with concatenated runs of transactions.\n\u003e\n\u003e 5) LZO should provide much better compression, at a cost of CPU\n\u003e performance and using a less-reviewed, less-field-tested library.\nI don't think LZO will give as good compression here but I will do some\nbenchmarking when I can.\n\n\u003e\n\u003e\n\u003e\n\u003e\n\u003e\n\u003e On Tue, Nov 10, 2015 at 11:30 AM, Tier Nolan via bitcoin-dev\n\u003e \u003cbitcoin-dev at lists.linuxfoundation.org\n\u003e \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\u003e wrote:\n\u003e\n\u003e\n\u003e\n\u003e On Tue, Nov 10, 2015 at 4:11 PM, Peter Tschipper\n\u003e \u003cpeter.tschipper at gmail.com \u003cmailto:peter.tschipper at gmail.com\u003e\u003e wrote:\n\u003e\n\u003e There are better ways of sending new blocks, that's certainly\n\u003e true but for sending historical blocks and seding transactions\n\u003e I don't think so. This PR is really designed to save\n\u003e bandwidth and not intended to be a huge performance\n\u003e improvement in terms of time spent sending.\n\u003e\n\u003e\n\u003e If the main point is for historical data, then sticking to just\n\u003e blocks is the best plan.\n\u003e\n\u003e Since small blocks don't compress well, you could define a\n\u003e \"cblocks\" message that handles multiple blocks (just concatenate\n\u003e the block messages as payload before compression). \n\u003e\n\u003e The sending peer could combine blocks so that each cblock is\n\u003e compressing at least 10kB of block data (or whatever is optimal). \n\u003e It is probably worth specifying a maximum size for network buffer\n\u003e reasons (either 1MB or 1 block maximum).\n\u003e\n\u003e Similarly, transactions could be combined together and compressed\n\u003e \"ctxs\". The inv messages could be modified so that you can\n\u003e request groups of 10-20 transactions. That would depend on how\n\u003e much of an improvement compressed transactions would represent.\n\u003e\n\u003e More generally, you could define a message which is a compressed\n\u003e message holder. That is probably to complex to be worth the\n\u003e effort though.\n\u003e\n\u003e \n\u003e\n\u003e\u003e\n\u003e\u003e On Tue, Nov 10, 2015 at 5:40 AM, Johnathan Corgan via\n\u003e\u003e bitcoin-dev \u003cbitcoin-dev at lists.linuxfoundation.org\n\u003e\u003e \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\u003e wrote:\n\u003e\u003e\n\u003e\u003e On Mon, Nov 9, 2015 at 5:58 PM, gladoscc via bitcoin-dev\n\u003e\u003e \u003cbitcoin-dev at lists.linuxfoundation.org\n\u003e\u003e \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\u003e wrote:\n\u003e\u003e \n\u003e\u003e\n\u003e\u003e I think 25% bandwidth savings is certainly\n\u003e\u003e considerable, especially for people running full\n\u003e\u003e nodes in countries like Australia where internet\n\u003e\u003e bandwidth is lower and there are data caps.\n\u003e\u003e\n\u003e\u003e\n\u003e\u003e ā This reinforces the idea that such trade-off decisions\n\u003e\u003e should be be local and negotiated between peers, not a\n\u003e\u003e required feature of the network P2P.ā\n\u003e\u003e \n\u003e\u003e\n\u003e\u003e -- \n\u003e\u003e Johnathan Corgan\n\u003e\u003e Corgan Labs - SDR Training and Development Services\n\u003e\u003e http://corganlabs.com\n\u003e\u003e\n\u003e\u003e _______________________________________________\n\u003e\u003e bitcoin-dev mailing list\n\u003e\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e\u003e \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\n\u003e\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e\u003e\n\u003e\u003e\n\u003e\u003e\n\u003e\u003e\n\u003e\u003e _______________________________________________\n\u003e\u003e bitcoin-dev mailing list\n\u003e\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e\u003e \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\n\u003e\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e\n\u003e\n\u003e\n\u003e _______________________________________________\n\u003e bitcoin-dev mailing list\n\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e \u003cmailto:bitcoin-dev at lists.linuxfoundation.org\u003e\n\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\u003e\n\u003e\n\u003e\n\u003e\n\u003e _______________________________________________\n\u003e bitcoin-dev mailing list\n\u003e bitcoin-dev at lists.linuxfoundation.org\n\u003e https://lists.linuxfoundation.org/mailman/listinfo/bitcoin-dev\n\n-------------- next part --------------\nAn HTML attachment was scrubbed...\nURL: \u003chttp://lists.linuxfoundation.org/pipermail/bitcoin-dev/attachments/20151110/1688b581/attachment.html\u003e",
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