transmission/libtransmission/bandwidth.c

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/*
* This file Copyright (C) 2008 Charles Kerr <charles@rebelbase.com>
*
* This file is licensed by the GPL version 2. Works owned by the
* Transmission project are granted a special exemption to clause 2(b)
* so that the bulk of its code can remain under the MIT license.
* This exemption does not extend to derived works not owned by
* the Transmission project.
*
* $Id:$
*/
#include <assert.h>
#include <limits.h>
#include "event.h"
#include "transmission.h"
#include "bandwidth.h"
#include "iobuf.h"
#include "ptrarray.h"
#include "utils.h"
/***
****
***/
enum
{
HISTORY_MSEC = 2000,
INTERVAL_MSEC = HISTORY_MSEC,
GRANULARITY_MSEC = 40,
HISTORY_SIZE = ( INTERVAL_MSEC / GRANULARITY_MSEC ),
MAGIC_NUMBER = 43143
};
struct bratecontrol
{
int newest;
struct { uint64_t date, size; } transfers[HISTORY_SIZE];
};
static float
getSpeed( const struct bratecontrol * r, int interval_msec )
{
uint64_t bytes = 0;
const uint64_t cutoff = tr_date ( ) - interval_msec;
int i = r->newest;
for( ;; )
{
if( r->transfers[i].date <= cutoff )
break;
bytes += r->transfers[i].size;
if( --i == -1 ) i = HISTORY_SIZE - 1; /* circular history */
if( i == r->newest ) break; /* we've come all the way around */
}
return ( bytes / 1024.0 ) * ( 1000.0 / interval_msec );
}
static void
bytesUsed( struct bratecontrol * r, size_t size )
{
const uint64_t now = tr_date ( );
if( r->transfers[r->newest].date + GRANULARITY_MSEC >= now )
r->transfers[r->newest].size += size;
else
{
if( ++r->newest == HISTORY_SIZE ) r->newest = 0;
r->transfers[r->newest].date = now;
r->transfers[r->newest].size = size;
}
}
/******
*******
*******
******/
struct tr_band
{
tr_bool isLimited;
tr_bool honorParentLimits;
size_t bytesLeft;
double desiredSpeed;
struct bratecontrol raw;
struct bratecontrol piece;
};
struct tr_bandwidth
{
struct tr_band band[2];
struct tr_bandwidth * parent;
int magicNumber;
tr_session * session;
tr_ptrArray * children; /* struct tr_bandwidth */
tr_ptrArray * iobufs; /* struct tr_iobuf */
};
/***
****
***/
static int
comparePointers( const void * a, const void * b )
{
return a - b;
}
static int
isBandwidth( const tr_bandwidth * b )
{
return ( b != NULL ) && ( b->magicNumber == MAGIC_NUMBER );
}
static int
isDirection( const tr_direction dir )
{
return ( dir == TR_UP ) || ( dir == TR_DOWN );
}
/***
****
***/
tr_bandwidth*
tr_bandwidthNew( tr_session * session, tr_bandwidth * parent )
{
tr_bandwidth * b = tr_new0( tr_bandwidth, 1 );
b->session = session;
b->children = tr_ptrArrayNew( );
b->iobufs = tr_ptrArrayNew( );
b->magicNumber = MAGIC_NUMBER;
b->band[TR_UP].honorParentLimits = 1;
b->band[TR_DOWN].honorParentLimits = 1;
tr_bandwidthSetParent( b, parent );
return b;
}
void
tr_bandwidthFree( tr_bandwidth * b )
{
assert( isBandwidth( b ) );
tr_bandwidthSetParent( b, NULL );
tr_ptrArrayFree( b->iobufs, NULL );
tr_ptrArrayFree( b->children, NULL );
b->magicNumber = 0xDEAD;
tr_free( b );
}
/***
****
***/
void
tr_bandwidthSetParent( tr_bandwidth * b,
tr_bandwidth * parent )
{
assert( isBandwidth( b ) );
assert( b != parent );
if( b->parent )
{
assert( isBandwidth( b->parent ) );
tr_ptrArrayRemoveSorted( b->parent->children, b, comparePointers );
b->parent= NULL;
}
if( parent )
{
assert( isBandwidth( parent ) );
assert( parent->parent != b );
tr_ptrArrayInsertSorted( parent->children, b, comparePointers );
b->parent = parent;
}
}
void
tr_bandwidthHonorParentLimits( tr_bandwidth * b,
tr_direction dir,
int honorParentLimits )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
b->band[dir].honorParentLimits = honorParentLimits != 0;
}
/***
****
***/
void
tr_bandwidthSetDesiredSpeed( tr_bandwidth * b,
tr_direction dir,
double desiredSpeed )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
b->band[dir].desiredSpeed = desiredSpeed;
}
double
tr_bandwidthGetDesiredSpeed( const tr_bandwidth * b,
tr_direction dir )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
return b->band[dir].desiredSpeed;
}
void
tr_bandwidthSetLimited( tr_bandwidth * b,
tr_direction dir,
int isLimited )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
b->band[dir].isLimited = isLimited != 0;
}
int
tr_bandwidthIsLimited( const tr_bandwidth * b,
tr_direction dir )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
return b->band[dir].isLimited != 0;
}
2008-11-26 18:54:35 +00:00
#if 0
#warning do not check the code in with this enabled
#define DEBUG_DIRECTION TR_UP
#endif
void
tr_bandwidthAllocate( tr_bandwidth * b,
tr_direction dir,
int period_msec )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
if( b->band[dir].isLimited )
{
const double currentSpeed = getSpeed( &b->band[dir].piece, HISTORY_MSEC - period_msec );
const double desiredSpeed = b->band[dir].desiredSpeed;
const double pulseCount = ( HISTORY_MSEC - period_msec ) / (double)period_msec;
const double nextPulseSpeed = desiredSpeed * ( pulseCount + 1 ) - ( currentSpeed * pulseCount );
b->band[dir].bytesLeft = MAX( 0.0, nextPulseSpeed * 1024.0 * period_msec / 1000.0 );
#ifdef DEBUG_DIRECTION
if( dir == DEBUG_DIRECTION )
fprintf( stderr, "bandwidth %p currentPieceSpeed(%5.2f of %5.2f) desiredSpeed(%5.2f), allocating %5.2f\n",
b, currentSpeed, tr_bandwidthGetRawSpeed( b, dir ), desiredSpeed,
b->band[dir].bytesLeft/1024.0 );
#endif
}
/* notify the io buffers that there's more bandwidth available */
if( !b->band[dir].isLimited || ( b->band[dir].bytesLeft > 0 ) )
{
int i, n=0;
short what = dir==TR_UP ? EV_WRITE : EV_READ;
struct tr_iobuf ** iobufs = (struct tr_iobuf**) tr_ptrArrayPeek( b->iobufs, &n );
#ifdef DEBUG_DIRECTION
if( ( dir == DEBUG_DIRECTION ) && ( n > 1 ) )
fprintf( stderr, "bandwidth %p has %d iobufs\n", b, n );
#endif
for( i=0; i<n; ++i )
tr_iobuf_enable( iobufs[i], what );
}
/* all children should reallocate too */
if( 1 ) {
int i, n=0;
struct tr_bandwidth ** children = (struct tr_bandwidth**) tr_ptrArrayPeek( b->children, &n );
for( i=0; i<n; ++i )
tr_bandwidthAllocate( children[i], dir, period_msec );
}
}
/***
****
***/
void
tr_bandwidthAddBuffer( tr_bandwidth * b,
struct tr_iobuf * iobuf )
{
assert( isBandwidth( b ) );
assert( iobuf );
tr_ptrArrayInsertSorted( b->iobufs, iobuf, comparePointers );
}
void
tr_bandwidthRemoveBuffer( tr_bandwidth * b,
struct tr_iobuf * iobuf )
{
assert( isBandwidth( b ) );
assert( iobuf );
tr_ptrArrayRemoveSorted( b->iobufs, iobuf, comparePointers );
}
/***
****
***/
size_t
tr_bandwidthClamp( const tr_bandwidth * b,
tr_direction dir,
size_t byteCount )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
if( b )
{
if( b->band[dir].isLimited )
byteCount = MIN( byteCount, b->band[dir].bytesLeft );
if( b->parent && b->band[dir].honorParentLimits )
byteCount = tr_bandwidthClamp( b->parent, dir, byteCount );
}
return byteCount;
}
double
tr_bandwidthGetRawSpeed( const tr_bandwidth * b, tr_direction dir )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
return getSpeed( &b->band[dir].raw, HISTORY_MSEC );
}
double
tr_bandwidthGetPieceSpeed( const tr_bandwidth * b, tr_direction dir )
{
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
return getSpeed( &b->band[dir].piece, HISTORY_MSEC );
}
void
tr_bandwidthUsed( tr_bandwidth * b,
tr_direction dir,
size_t byteCount,
int isPieceData )
{
struct tr_band * band;
size_t oldBytesLeft;
assert( isBandwidth( b ) );
assert( isDirection( dir ) );
band = &b->band[dir];
oldBytesLeft = band->bytesLeft;
if( band->isLimited && isPieceData )
band->bytesLeft -= MIN( band->bytesLeft, byteCount );
#ifdef DEBUG_DIRECTION
if( ( dir == DEBUG_DIRECTION ) && ( band->isLimited ) )
fprintf( stderr, "%p consumed %5zu bytes of %5s data... was %6zu, now %6zu left\n",
b, byteCount, (isPieceData?"piece":"raw"), oldBytesLeft, band->bytesLeft );
#endif
bytesUsed( &band->raw, byteCount );
if( isPieceData )
bytesUsed( &band->piece, byteCount );
if( b->parent != NULL )
tr_bandwidthUsed( b->parent, dir, byteCount, isPieceData );
}