7473c93668
We don't have a UDP which specifies any messages that will be 4KB. Aside from being implemented for months and a necessity for encryption and piggy-backing packets, 1280bytes is ideal, and, means this TODO can be completed! Why 1280 bytes? * It's less than the default MTU for most WAN/LAN networks. That means fewer fragmented datagrams (esp on well-connected networks). * Fragmented datagrams and dropped packets suck and add latency while OS waits for a dropped fragment to never arrive (blocking readLoop()) * Most of our packets are < 1280 bytes. * 1280 bytes is minimum datagram size and MTU for IPv6 -- on IPv6, a datagram < 1280bytes will *never* be fragmented. UDP datagrams are dropped. A lot! And fragmented datagrams are worse. If a datagram has a 30% chance of being dropped, then a fragmented datagram has a 60% chance of being dropped. More importantly, we have signed packets and can't do anything with a packet unless we receive the entire datagram because the signature can't be verified. The same is true when we have encrypted packets. So the solution here to picking an ideal buffer size for receiving datagrams is a number under 1400bytes. And the lower-bound value for IPv6 of 1280 bytes make's it a non-decision. On IPv4 most ISPs and 3g/4g/let networks have an MTU just over 1400 -- and *never* over 1500. Never -- that means packets over 1500 (in reality: ~1450) bytes are fragmented. And probably dropped a lot. Just to prove the point, here are pings sending non-fragmented packets over wifi/ISP, and a second set of pings via cell-phone tethering. It's important to note that, if *any* router between my system and the EC2 node has a lower MTU, the message would not go through: On wifi w/normal ISP: localhost:Debug $ ping -D -s 1450 52.6.250.242 PING 52.6.250.242 (52.6.250.242): 1450 data bytes 1458 bytes from 52.6.250.242: icmp_seq=0 ttl=42 time=104.831 ms 1458 bytes from 52.6.250.242: icmp_seq=1 ttl=42 time=119.004 ms ^C --- 52.6.250.242 ping statistics --- 2 packets transmitted, 2 packets received, 0.0% packet loss round-trip min/avg/max/stddev = 104.831/111.918/119.004/7.087 ms localhost:Debug $ ping -D -s 1480 52.6.250.242 PING 52.6.250.242 (52.6.250.242): 1480 data bytes ping: sendto: Message too long ping: sendto: Message too long Request timeout for icmp_seq 0 ping: sendto: Message too long Request timeout for icmp_seq 1 Tethering to O2: localhost:Debug $ ping -D -s 1480 52.6.250.242 PING 52.6.250.242 (52.6.250.242): 1480 data bytes ping: sendto: Message too long ping: sendto: Message too long Request timeout for icmp_seq 0 ^C --- 52.6.250.242 ping statistics --- 2 packets transmitted, 0 packets received, 100.0% packet loss localhost:Debug $ ping -D -s 1450 52.6.250.242 PING 52.6.250.242 (52.6.250.242): 1450 data bytes 1458 bytes from 52.6.250.242: icmp_seq=0 ttl=42 time=107.844 ms 1458 bytes from 52.6.250.242: icmp_seq=1 ttl=42 time=105.127 ms 1458 bytes from 52.6.250.242: icmp_seq=2 ttl=42 time=120.483 ms 1458 bytes from 52.6.250.242: icmp_seq=3 ttl=42 time=102.136 ms |
||
|---|---|---|
| Godeps | ||
| _data | ||
| accounts | ||
| build | ||
| cmd | ||
| common | ||
| compression/rle | ||
| core | ||
| crypto | ||
| docker | ||
| errs | ||
| eth | ||
| ethdb | ||
| event | ||
| generators | ||
| jsre | ||
| logger | ||
| miner | ||
| p2p | ||
| params | ||
| pow | ||
| rlp | ||
| rpc | ||
| tests | ||
| trie | ||
| ui | ||
| whisper | ||
| xeth | ||
| .gitignore | ||
| .gitmodules | ||
| .mailmap | ||
| .travis.yml | ||
| LICENSE | ||
| Makefile | ||
| README.md | ||
| update-license.go | ||
README.md
Ethereum Go
Ethereum Go Client © 2014 Jeffrey Wilcke.
| Linux | OSX | Windows | Tests
----------|---------|-----|---------|------
develop | |
|
|
master | |
|
|
Automated (dev) builds
- Docker
- OS X
- Ubuntu trusty | utopic
- Windows 64-bit
Building the source
For prerequisites and detailed build instructions please read the Installation Instructions on the wiki.
Building geth requires two external dependencies, Go and GMP. You can install them using your favourite package manager. Once the dependencies are installed, run
make geth
Executables
Go Ethereum comes with several wrappers/executables found in
the cmd directory:
mistOfficial Ethereum Browser (ethereum GUI client)gethEthereum CLI (ethereum command line interface client)bootnoderuns a bootstrap node for the Discovery Protocolethtesttest tool which runs with the tests suite:cat file | ethtest.evmis a generic Ethereum Virtual Machine:evm -code 60ff60ff -gas 10000 -price 0 -dump. See-hfor a detailed description.disasmdisassembles EVM code:echo "6001" | disasmrlpdumpprints RLP structures
Command line options
Both mist and geth can be configured via command line options, environment variables and config files.
To get the options available:
geth --help
For further details on options, see the wiki
Contribution
If you'd like to contribute to go-ethereum please fork, fix, commit and
send a pull request. Commits who do not comply with the coding standards
are ignored (use gofmt!). If you send pull requests make absolute sure that you
commit on the develop branch and that you do not merge to master.
Commits that are directly based on master are simply ignored.
See Developers' Guide for more details on configuring your environment, testing, and dependency management.