Return-Path: Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id 98B8D901 for ; Wed, 2 Dec 2015 23:05:13 +0000 (UTC) X-Greylist: whitelisted by SQLgrey-1.7.6 Received: from mail-pf0-f181.google.com (mail-pf0-f181.google.com [209.85.192.181]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id BE091140 for ; Wed, 2 Dec 2015 23:05:12 +0000 (UTC) Received: by pfu207 with SMTP id 207so2347726pfu.2 for ; Wed, 02 Dec 2015 15:05:12 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=subject:to:references:from:message-id:date:user-agent:mime-version :in-reply-to:content-type; bh=6ihD4BBBoqjX5lj64AasRSleLxwgImwM0RODfuTkoqY=; b=Uaqo6Lx9kSg+/5msTrMVLyu9ukl1XfsyHAjHYbwrRYj99Oe5Gfxxet5l1VtmnRZ0Qn SnC0ueR/7EIqLSRSNa5TL37wqmVjnrhjagEh4GA+U9ulE6qvwwDT9GKQghyoagl7pGjf egEWf7tjeCiKY+k95cXxXjwtVWJcJS6G/MznenL8kzrmQoa28H/QEc2yFhXOL5Yfq3qM 009KQu9XutVjfZFjhlmb4KQv+HjWm+NsmP4Ko8GgjWgpvAVB8+620cjjeQ0HLTbmR4lW qaRw04A5sj9d7QfUhrQa1cS1d0oS12UBF9rAIQkqEMPGMBUd16b0wQUWXpD7fT/yWYIP ELsg== X-Received: by 10.98.43.18 with SMTP id r18mr8626523pfr.2.1449097512511; Wed, 02 Dec 2015 15:05:12 -0800 (PST) Received: from [192.168.0.132] (S0106bcd165303d84.cc.shawcable.net. [96.54.102.88]) by smtp.googlemail.com with ESMTPSA id 25sm6410964pfp.62.2015.12.02.15.05.11 (version=TLSv1/SSLv3 cipher=OTHER); Wed, 02 Dec 2015 15:05:12 -0800 (PST) To: Matt Corallo , Bitcoin Dev References: <565CD7D8.3070102@gmail.com> <90EF4E6C-9A71-4A35-A938-EAFC1A24DD24@mattcorallo.com> From: Peter Tschipper X-Enigmail-Draft-Status: N1110 Message-ID: <565F7926.103@gmail.com> Date: Wed, 2 Dec 2015 15:05:10 -0800 User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101 Thunderbird/38.3.0 MIME-Version: 1.0 In-Reply-To: <90EF4E6C-9A71-4A35-A938-EAFC1A24DD24@mattcorallo.com> Content-Type: multipart/alternative; boundary="------------080601010707010102070301" X-Spam-Status: No, score=-2.7 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FROM,HTML_MESSAGE,RCVD_IN_DNSWL_LOW autolearn=ham version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on smtp1.linux-foundation.org Subject: Re: [bitcoin-dev] [BIP Draft] Datastream compression of Blocks and Transactions X-BeenThere: bitcoin-dev@lists.linuxfoundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Bitcoin Development Discussion List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 02 Dec 2015 23:05:13 -0000 This is a multi-part message in MIME format. --------------080601010707010102070301 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit On 30/11/2015 9:28 PM, Matt Corallo wrote: > I'm really not a fan of this at all. To start with, adding a compression library that is directly accessible to the network on financial software is a really, really scary idea. Why scary? LZO has no current security issues, and it will be configureable by each node operator so it can be turned off completely if needed or desired. > If there were a massive improvement, I'd find it acceptable, but the improvement you've shown really isn't all that much. Why is 15% at the low end, to 27% at the high end not good? It sounds like a very good boost. > The numbers you recently posted show it improving the very beginning of IBD somewhat over high-latency connections, but if we're throughput-limited after the very beginning of IBD, we should fix that, not compress the blocks. I only did the compression up to the 200,000 block to better isolate the transmission of data from the post processing of blocks and determine whether the compressing of data was adding to much to the total transmission time. I think it's clear from the data that as the data (blocks, transactions) increase in size that (1) they compress better and (2) they have a bigger and positive impact on improving performance when compressed. > Additionally, I'd be very surprised if this had any significant effect on the speed at which new blocks traverse the network (do you have any simulations or other thoughts on this?). From the table below, at 120000 blocks the time to sync the chain was roughly the same for compressed vs. uncompressed however after that point as block sizes start increasing, all compression libraries peformed much faster than uncompressed. The data provided in this testing clearly shows that as block size increases, the performance improvement by compressing data also increases. TABLE 5: Results shown in seconds with 60ms of induced latency Num blks sync'd Uncmp Zlib-1 Zlib-6 LZO1x-1 LZO1x-999 --------------- ----- ------ ------ ------- --------- 120000 3226 3416 3397 3266 3302 130000 4010 3983 3773 3625 3703 140000 4914 4503 4292 4127 4287 150000 5806 4928 4719 4529 4821 160000 6674 5249 5164 4840 5314 170000 7563 5603 5669 5289 6002 180000 8477 6054 6268 5858 6638 190000 9843 7085 7278 6868 7679 200000 11338 8215 8433 8044 8795 As far as, what happens after the block is received, then obviously compression isn't going to help in post processing and validating the block, but in the pure transmission of the object it most certainly and logically does and in a fairly direct proportion to the file size (a file that is 20% smaller will be transmited "at least" 20% faster, you can use any data transfer time calculator for that). The only issue, that I can see that required testing was to show how much compression there would be, and how much time the compression of the data would add to the sending of the data. --------------080601010707010102070301 Content-Type: text/html; charset=utf-8 Content-Transfer-Encoding: 8bit

On 30/11/2015 9:28 PM, Matt Corallo wrote:
I'm really not a fan of this at all. To start with, adding a compression library that is directly accessible to the network on financial software is a really, really scary idea.
Why scary?  LZO has no current security issues, and it will be configureable by each node operator so it can be turned off completely if needed or desired.  
If there were a massive improvement, I'd find it acceptable, but the improvement you've shown really isn't all that much.
Why is 15% at the low end, to 27% at the high end not good?  It sounds like a very good boost.    
 The numbers you recently posted show it improving the very beginning of IBD somewhat over high-latency connections, but if we're throughput-limited after the very beginning of IBD, we should fix that, not compress the blocks.
I only did the compression up to the 200,000 block to better isolate the transmission of data from the post processing of blocks and determine whether the compressing of data was adding to much to the total transmission time.

I think it's clear from the data that as the data (blocks, transactions) increase in size that (1) they compress better and (2) they have a bigger and positive impact on improving performance when compressed.

Additionally, I'd be very surprised if this had any significant effect on the speed at which new blocks traverse the network (do you have any simulations or other thoughts on this?).
From the table below, at 120000 blocks the time to sync the chain was roughly the same for compressed vs. uncompressed however after that point as block sizes start increasing, all compression libraries peformed much faster than uncompressed. The data provided in this testing clearly shows that as block size increases, the performance improvement by compressing data also increases.

TABLE 5:
Results shown in seconds with 60ms of induced latency
Num blks sync'd  Uncmp  Zlib-1  Zlib-6  LZO1x-1  LZO1x-999
---------------  -----  ------  ------  -------  ---------
120000           3226   3416    3397    3266     3302
130000           4010   3983    3773    3625     3703
140000           4914   4503    4292    4127     4287
150000           5806   4928    4719    4529     4821
160000           6674   5249    5164    4840     5314
170000           7563   5603    5669    5289     6002
180000           8477   6054    6268    5858     6638
190000           9843   7085    7278    6868     7679
200000           11338  8215    8433    8044     8795


As far as, what happens after the block is received, then obviously compression isn't going to help in post processing and validating the block, but in the pure transmission of the object it most certainly and logically does and in a fairly direct proportion to the file size (a file that is 20% smaller will be transmited "at least" 20% faster, you can use any data transfer time calculator for that).  The only issue, that I can see that required testing was to show how much compression there would be, and how much time the compression of the data would add to the sending of the data.

 
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