static void
phaseOne( tr_ptrArray * peerArray, tr_direction dir )
{
int i, n;
int peerCount = tr_ptrArraySize( peerArray );
struct tr_peerIo ** peers = (struct tr_peerIo**) tr_ptrArrayBase( peerArray );
/* First phase of IO. Tries to distribute bandwidth fairly to keep faster
* peers from starving the others. Loop through the peers, giving each a
* small chunk of bandwidth. Keep looping until we run out of bandwidth
* and/or peers that can use it */
n = peerCount;
dbgmsg( "%d peers to go round-robin for %s", n, (dir==TR_UP?"upload":"download") );
i = n ? tr_cryptoWeakRandInt( n ) : 0; /* pick a random starting point */
while( n > 1 )
{
const size_t increment = 1024;
const int bytesUsed = tr_peerIoFlush( peers[i], dir, increment );
dbgmsg( "peer #%d of %d used %d bytes in this pass", i, n, bytesUsed );
if( bytesUsed == (int)increment )
++i;
else {
/* peer is done writing for now; move it to the end of the list */
tr_peerIo * pio = peers[i];
peers[i] = peers[n-1];
peers[n-1] = pio;
--n;
}
if( i == n )
i = 0;
}
}
static void
phaseOne (tr_ptrArray * peerArray, tr_direction dir)
{
int n;
int peerCount = tr_ptrArraySize (peerArray);
struct tr_peerIo ** peers = (struct tr_peerIo**) tr_ptrArrayBase (peerArray);
/* First phase of IO. Tries to distribute bandwidth fairly to keep faster
* peers from starving the others. Loop through the peers, giving each a
* small chunk of bandwidth. Keep looping until we run out of bandwidth
* and/or peers that can use it */
n = peerCount;
dbgmsg ("%d peers to go round-robin for %s", n, (dir==TR_UP?"upload":"download"));
while (n > 0)
{
const int i = tr_cryptoWeakRandInt (n); /* pick a peer at random */
/* value of 3000 bytes chosen so that when using uTP we'll send a full-size
* frame right away and leave enough buffered data for the next frame to go
* out in a timely manner. */
const size_t increment = 3000;
const int bytesUsed = tr_peerIoFlush (peers[i], dir, increment);
dbgmsg ("peer #%d of %d used %d bytes in this pass", i, n, bytesUsed);
if (bytesUsed != (int)increment) {
/* peer is done writing for now; move it to the end of the list */
tr_peerIo * pio = peers[i];
peers[i] = peers[n-1];
peers[n-1] = pio;
--n;
}
}
}
int
tr_peerIoFlushOutgoingProtocolMsgs( tr_peerIo * io )
{
size_t byteCount = 0;
tr_list * it;
/* count up how many bytes are used by non-piece-data messages
at the front of our outbound queue */
for( it=io->outbuf_datatypes; it!=NULL; it=it->next )
{
struct tr_datatype * d = it->data;
if( d->isPieceData )
break;
byteCount += d->length;
}
return tr_peerIoFlush( io, TR_UP, byteCount );
}
void
tr_bandwidthAllocate( tr_bandwidth * b,
tr_direction dir,
int period_msec )
{
int i, n, peerCount;
tr_ptrArray * tmp;
struct tr_peerIo ** peers;
const uint64_t now = tr_date( );
const uint64_t cutoff = now + 100; /* 1/10th of a second */
/* allocateBandwidth() is a helper function with two purposes:
* 1. allocate bandwidth to b and its subtree
* 2. accumulate an array of all the peerIos from b and its subtree. */
tmp = tr_ptrArrayNew( );
allocateBandwidth( b, dir, period_msec, tmp );
peers = (struct tr_peerIo**) tr_ptrArrayPeek( tmp, &peerCount );
/* Stop all peers from listening for the socket to be ready for IO.
* See "Second phase of IO" lower in this function for more info. */
for( i=0; i<peerCount; ++i )
tr_peerIoSetEnabled( peers[i], dir, FALSE );
/* First phase of IO. Tries to distribute bandwidth fairly to keep faster
* peers from starving the others. Loop through the peers, giving each a
* small chunk of bandwidth. Keep looping until we run out of bandwidth
* or peers that can use it */
n = peerCount;
i = n ? tr_cryptoWeakRandInt( n ) : 0; /* pick a random starting point */
for( ; n>0 && tr_date()<=cutoff; )
{
const int increment = n==1 ? 4096 : 1024;
const int byteCount = tr_peerIoFlush( peers[i], dir, increment);
if( byteCount == increment )
++i;
else {
/* peer is done writing for now; move it to the end of the list */
tr_peerIo * tmp = peers[i];
peers[i] = peers[n-1];
peers[n-1] = tmp;
--n;
}
assert( i <= n );
if( i == n )
i = 0;
}
/* Second phase of IO. To help us scale in high bandwidth situations,
* enable on-demand IO for peers with bandwidth left to burn.
* This on-demand IO is enabled until (1) the peer runs out of bandwidth,
* or (2) the next tr_bandwidthAllocate() call, when we start over again. */
for( i=0; i<peerCount; ++i )
if( tr_peerIoHasBandwidthLeft( peers[i], dir ) )
tr_peerIoSetEnabled( peers[i], dir, TRUE );
/* cleanup */
tr_ptrArrayFree( tmp, NULL );
}