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add some comments on peer profile size

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zzz
2009-03-04 04:16:57 +00:00
parent 1d690f46ae
commit 54f1c0ec66
1 changed files with 47 additions and 3 deletions
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50
router/java/src/net/i2p/router/peermanager/PeerProfile.java
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@ -8,6 +8,21 @@ import net.i2p.router.RouterContext;
import net.i2p.stat.RateStat;
import net.i2p.util.Log;
/**
* Copied from http://www.i2p2.i2p/how_peerselection.html
*
* See also main() below for additional commentary by zzz.
*
* Currently, there is no 'ejection' strategy to get rid of the profiles for peers that
* are no longer active (or when the network consists of thousands of peers, to get rid
* of peers that are performing poorly). However, the size of each profile is fairly small,
* and is unrelated to how much data is collected about the peer, so that a router can
* keep a few thousand active peer profiles before the overhead becomes a serious concern.
* Once it becomes necessary, we can simply compact the poorly performing profiles
* (keeping only the most basic data) and maintain hundreds of thousands of profiles
* in memory. Beyond that size, we can simply eject the peers (e.g. keeping the best 100,000).
*/
public class PeerProfile {
private Log _log;
private RouterContext _context;
@ -315,6 +330,11 @@ public class PeerProfile {
}
}
}
/**
* @return the average of the three fastest one-minute data transfers, on a per-tunnel basis,
* through this peer. Ever. Except that the peak values are cut in half
* once a day by coalesceThroughput(). This seems way too seldom.
*/
public double getPeakTunnel1mThroughputKBps() {
double rv = 0;
for (int i = 0; i < THROUGHPUT_COUNT; i++)
@ -504,12 +524,36 @@ public class PeerProfile {
public String toString() { return "Profile: " + getPeer().toBase64(); }
/**
* New measurement is 12KB per expanded profile. (2009-03 zzz)
* And nowhere in the code is shrinkProfile() called so
* the size of compact profiles doesn't matter right now.
* This is far bigger than the NetDB entry, which is only about 1.5KB
* now that most of the stats have been removed.
*
* The biggest user in the profile is the Rates. (144 bytes per according to jhat).
* PeerProfile: 9 RateStats, 3-5 Rates each - 35 total
* DBHistory: 2 RateStats, 3 each - 6 total
* TunnelHistory: 4 RateStats, 5 each - 20 total
* --- ---------
* 15 61 total
* *60 bytes *144 bytes
* --- ---------
* 900 bytes 8784 bytes
*
* The RateStat itself is 32 bytes and the Rate[] is 28 so that adds
* about 1KB.
*
* So two obvious things to do are cut out some of the Rates,
* and call shrinkProfile().
*
* Obsolete calculation follows:
*
* Calculate the memory consumption of profiles. Measured to be ~3739 bytes
* for an expanded profile, and ~212 bytes for a compacted one.
*
*/
public static void main2(String args[]) {
RouterContext ctx = new RouterContext(null);
public static void main(String args[]) {
RouterContext ctx = new RouterContext(new net.i2p.router.Router());
testProfileSize(ctx, 100, 0); // 560KB
testProfileSize(ctx, 1000, 0); // 3.9MB
testProfileSize(ctx, 10000, 0); // 37MB
@ -524,7 +568,7 @@ public class PeerProfile {
* PeerProfile [filename]*
* </pre>
*/
public static void main(String args[]) {
public static void main2(String args[]) {
RouterContext ctx = new RouterContext(new net.i2p.router.Router());
DecimalFormat fmt = new DecimalFormat("0,000.0");
fmt.setPositivePrefix("+");