void
tr_bandwidthAllocate( tr_bandwidth * b,
tr_direction dir,
unsigned int period_msec )
{
int i, peerCount;
tr_ptrArray tmp = TR_PTR_ARRAY_INIT;
tr_ptrArray low = TR_PTR_ARRAY_INIT;
tr_ptrArray high = TR_PTR_ARRAY_INIT;
tr_ptrArray normal = TR_PTR_ARRAY_INIT;
struct tr_peerIo ** peers;
/* 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. */
allocateBandwidth( b, TR_PRI_LOW, dir, period_msec, &tmp );
peers = (struct tr_peerIo**) tr_ptrArrayBase( &tmp );
peerCount = tr_ptrArraySize( &tmp );
for( i=0; i<peerCount; ++i )
{
tr_peerIo * io = peers[i];
tr_peerIoRef( io );
tr_peerIoFlushOutgoingProtocolMsgs( io );
switch( io->priority ) {
case TR_PRI_HIGH:
tr_ptrArrayAppend( &high, io ); /* fall through */
case TR_PRI_NORMAL:
tr_ptrArrayAppend( &normal, io ); /* fall through */
default:
tr_ptrArrayAppend( &low, io );
}
}
/* 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 */
phaseOne( &high, dir );
phaseOne( &normal, dir );
phaseOne( &low, dir );
/* 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 )
tr_peerIoSetEnabled( peers[i], dir, tr_peerIoHasBandwidthLeft( peers[i], dir ) );
for( i=0; i<peerCount; ++i )
tr_peerIoUnref( peers[i] );
/* cleanup */
tr_ptrArrayDestruct( &normal, NULL );
tr_ptrArrayDestruct( &high, NULL );
tr_ptrArrayDestruct( &low, NULL );
tr_ptrArrayDestruct( &tmp, NULL );
}
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 );
}
