Files
rippled/src/LedgerTiming.cpp
2012-07-12 01:43:35 -07:00

91 lines
3.2 KiB
C++

#include "LedgerTiming.h"
#include <cassert>
// NOTE: First and last times must be repeated
int ContinuousLedgerTiming::LedgerTimeResolution[] = { 10, 10, 20, 30, 60, 90, 120, 120 };
// Called when a ledger is open and no close is in progress -- when a transaction is received and no close
// is in process, or when a close completes. Returns the number of seconds the ledger should be be open.
int ContinuousLedgerTiming::shouldClose(
bool anyTransactions,
int previousProposers, // proposers in the last closing
int proposersClosed, // proposers who have currently closed this ledgers
int previousSeconds, // seconds the previous ledger took to reach consensus
int currentSeconds) // seconds since the previous ledger closed
{
if (!anyTransactions)
{ // no transactions so far this interval
if (proposersClosed > (previousProposers / 4)) // did we miss a transaction?
return currentSeconds;
if (previousSeconds > (LEDGER_IDLE_INTERVAL + 2)) // the last ledger was very slow to close
return previousSeconds - 1;
return LEDGER_IDLE_INTERVAL; // normal idle
}
if (previousSeconds == LEDGER_IDLE_INTERVAL) // coming out of idle, close now
return currentSeconds;
// If the network is slow, try to synchronize close times
if (previousSeconds > 8)
return (currentSeconds - currentSeconds % 4);
else if (previousSeconds > 4)
return (currentSeconds - currentSeconds % 2);
return currentSeconds; // this ledger should close now
}
// Returns whether we have a consensus or not. If so, we expect all honest nodes
// to already have everything they need to accept a consensus. Our vote is 'locked in'.
bool ContinuousLedgerTiming::haveConsensus(
int previousProposers, // proposers in the last closing (not including us)
int currentProposers, // proposers in this closing so far (not including us)
int currentAgree, // proposers who agree with us
int currentClosed, // proposers who have currently closed their ledgers
int previousAgreeTime, // how long it took to agree on the last ledger
int currentAgreeTime) // how long we've been trying to agree
{
if (currentAgreeTime <= LEDGER_MIN_CONSENSUS)
return false;
if (currentProposers < (previousProposers * 3 / 4))
{ // Less than 3/4 of the last ledger's proposers are present, we may need more time
if (currentAgreeTime < (previousAgreeTime + 2))
return false;
}
// If 80% of current proposers (plus us) agree on a set, we have consensus
if (((currentAgree * 100 + 100) / (currentProposers + 1)) > 80)
return true;
// If 50% of the nodes on your UNL (minus us) have closed, you should close
if (((currentClosed * 100 - 100) / (currentProposers + 1)) > 50)
return true;
// no consensus yet
return false;
}
int ContinuousLedgerTiming::getNextLedgerTimeResolution(int previousResolution, bool previousAgree, int ledgerSeq)
{
assert(ledgerSeq);
if ((!previousAgree) && ((ledgerSeq % LEDGER_RES_DECREASE) == 0))
{ // reduce resolution
int i = 1;
while (LedgerTimeResolution[i] != previousResolution)
++i;
return LedgerTimeResolution[i - 1];
}
if ((previousAgree) && ((ledgerSeq % LEDGER_RES_INCREASE) == 0))
{ // increase resolution
int i = 1;
while (LedgerTimeResolution[i] != previousResolution)
++i;
return LedgerTimeResolution[i + 1];
}
return previousResolution;
}