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transmission/libtransmission/bandwidth.cc
Charles Kerr 19543ba65f
fix: clang-tidy-20 warnings (#7187)
* fix: readability-math-missing-parentheses clang-tidy warnings

* chore: remove unused function tr_ctorGetSession()

* chore: remove unused function tr_ctorGetIncompleteDir()

* chore: make generatePublicKey() a lambda

* fix: readability-container-contains warnings

* fix: misc-use-internal-linkage warnings

* chore: inline generate_public_key() since it was only used once
2024-10-21 20:57:01 -05:00

337 lines
9.3 KiB
C++

// This file Copyright © Mnemosyne LLC.
// It may be used under GPLv2 (SPDX: GPL-2.0-only), GPLv3 (SPDX: GPL-3.0-only),
// or any future license endorsed by Mnemosyne LLC.
// License text can be found in the licenses/ folder.
#include <algorithm>
#include <array>
#include <cstddef>
#include <cstdint>
#include <initializer_list>
#include <limits>
#include <memory>
#include <utility> // for std::swap()
#include <vector>
#include <fmt/core.h>
#include "libtransmission/transmission.h"
#include "libtransmission/bandwidth.h"
#include "libtransmission/crypto-utils.h"
#include "libtransmission/log.h"
#include "libtransmission/peer-io.h"
#include "libtransmission/tr-assert.h"
#include "libtransmission/utils.h" // tr_time_msec()
#include "libtransmission/values.h"
using namespace libtransmission::Values;
Speed tr_bandwidth::get_speed(RateControl& r, unsigned int interval_msec, uint64_t now)
{
if (now == 0U)
{
now = tr_time_msec();
}
if (now != r.cache_time_)
{
uint64_t bytes = 0U;
uint64_t const cutoff = now - interval_msec;
for (int i = r.newest_; r.date_[i] > cutoff;)
{
bytes += r.size_[i];
if (--i == -1)
{
i = HistorySize - 1; /* circular history */
}
if (i == r.newest_)
{
break; /* we've come all the way around */
}
}
r.cache_val_ = Speed{ bytes * 1000U / interval_msec, Speed::Units::Byps };
r.cache_time_ = now;
}
return r.cache_val_;
}
void tr_bandwidth::notify_bandwidth_consumed_bytes(uint64_t const now, RateControl& r, size_t size)
{
if (r.date_[r.newest_] + GranularityMSec >= now)
{
r.size_[r.newest_] += size;
}
else
{
if (++r.newest_ == HistorySize)
{
r.newest_ = 0;
}
r.date_[r.newest_] = now;
r.size_[r.newest_] = size;
}
/* invalidate cache_val*/
r.cache_time_ = 0U;
}
// ---
tr_bandwidth::tr_bandwidth(tr_bandwidth* parent, bool is_group)
: priority_(is_group ? std::numeric_limits<tr_priority_t>::max() : TR_PRI_NORMAL)
{
set_parent(parent);
}
// ---
namespace
{
namespace deparent_helpers
{
void remove_child(std::vector<tr_bandwidth*>& v, tr_bandwidth* remove_me) noexcept
{
// the list isn't sorted -- so instead of erase()ing `it`,
// do the cheaper option of overwriting it with the final item
if (auto it = std::find(std::begin(v), std::end(v), remove_me); it != std::end(v))
{
std::swap(*it, v.back());
v.pop_back();
}
}
} // namespace deparent_helpers
} // namespace
void tr_bandwidth::deparent() noexcept
{
using namespace deparent_helpers;
if (parent_ == nullptr)
{
return;
}
remove_child(parent_->children_, this);
parent_ = nullptr;
}
void tr_bandwidth::set_parent(tr_bandwidth* new_parent)
{
TR_ASSERT(this != new_parent);
deparent();
if (new_parent != nullptr)
{
#ifdef TR_ENABLE_ASSERTS
TR_ASSERT(new_parent->parent_ != this);
auto& children = new_parent->children_;
TR_ASSERT(std::find(std::begin(children), std::end(children), this) == std::end(children)); // not already there
#endif
new_parent->children_.push_back(this);
parent_ = new_parent;
}
}
// ---
void tr_bandwidth::allocate_bandwidth(
tr_priority_t parent_priority,
uint64_t period_msec,
std::vector<std::shared_ptr<tr_peerIo>>& peer_pool)
{
auto const priority = std::min(parent_priority, priority_);
// set the available bandwidth
for (auto const dir : { TR_UP, TR_DOWN })
{
if (auto& bandwidth = band_[dir]; bandwidth.is_limited_)
{
auto const next_pulse_speed = bandwidth.desired_speed_;
bandwidth.bytes_left_ = next_pulse_speed.base_quantity() * period_msec / 1000U;
}
}
// add this bandwidth's peer, if any, to the peer pool
if (auto shared = peer_.lock(); shared)
{
TR_ASSERT(tr_isPriority(priority));
shared->set_priority(priority);
peer_pool.push_back(std::move(shared));
}
// traverse & repeat for the subtree
for (auto* child : children_)
{
child->allocate_bandwidth(priority, period_msec, peer_pool);
}
}
void tr_bandwidth::phase_one(std::vector<tr_peerIo*>& peers, tr_direction dir)
{
// First phase of IO. Tries to distribute bandwidth fairly to keep faster
// peers from starving the others.
tr_logAddTrace(fmt::format("{} peers to go round-robin for {}", peers.size(), dir == TR_UP ? "upload" : "download"));
// Shuffle the peers so they all have equal chance to be first in line.
static thread_local auto urbg = tr_urbg<size_t>{};
std::shuffle(std::begin(peers), std::end(peers), urbg);
// Give each peer `Increment` bandwidth bytes to use. Repeat this
// process until we run out of bandwidth and/or peers that can use it.
for (size_t n_unfinished = std::size(peers); n_unfinished > 0U;)
{
for (size_t i = 0U; i < n_unfinished;)
{
// Value of 3000 bytes chosen so that when using µTP 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.
static auto constexpr Increment = 3000U;
auto const bytes_used = peers[i]->flush(dir, Increment);
tr_logAddTrace(fmt::format("peer #{} of {} used {} bytes in this pass", i, n_unfinished, bytes_used));
if (bytes_used != Increment)
{
// peer is done writing for now; move it to the end of the list
std::swap(peers[i], peers[n_unfinished - 1]);
--n_unfinished;
}
else
{
++i;
}
}
}
}
void tr_bandwidth::allocate(uint64_t period_msec)
{
// keep these peers alive for the scope of this function
auto refs = std::vector<std::shared_ptr<tr_peerIo>>{};
auto peer_arrays = std::array<std::vector<tr_peerIo*>, 3>{};
auto& high = peer_arrays[0];
auto& normal = peer_arrays[1];
auto& low = peer_arrays[2];
// 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.
allocate_bandwidth(std::numeric_limits<tr_priority_t>::max(), period_msec, refs);
for (auto const& io : refs)
{
io->flush_outgoing_protocol_msgs();
switch (io->priority())
{
case TR_PRI_HIGH:
high.push_back(io.get());
[[fallthrough]];
case TR_PRI_NORMAL:
normal.push_back(io.get());
[[fallthrough]];
case TR_PRI_LOW:
low.push_back(io.get());
break;
default:
TR_ASSERT_MSG(false, "invalid priority");
break;
}
}
// 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
for (auto& peers : peer_arrays)
{
phase_one(peers, TR_UP);
phase_one(peers, TR_DOWN);
}
// 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_bandwidth::allocate () call, when we start over again.
for (auto const& io : refs)
{
io->set_enabled(TR_UP, io->has_bandwidth_left(TR_UP));
io->set_enabled(TR_DOWN, io->has_bandwidth_left(TR_DOWN));
}
}
// ---
size_t tr_bandwidth::clamp(tr_direction const dir, size_t byte_count) const noexcept
{
TR_ASSERT(tr_isDirection(dir));
if (band_[dir].is_limited_)
{
byte_count = std::min(byte_count, band_[dir].bytes_left_);
}
if (parent_ != nullptr && band_[dir].honor_parent_limits_ && byte_count > 0U)
{
byte_count = parent_->clamp(dir, byte_count);
}
return byte_count;
}
void tr_bandwidth::notify_bandwidth_consumed(tr_direction dir, size_t byte_count, bool is_piece_data, uint64_t now)
{
TR_ASSERT(tr_isDirection(dir));
auto& band = band_[dir];
if (band.is_limited_ && is_piece_data)
{
band.bytes_left_ -= std::min(band.bytes_left_, byte_count);
}
notify_bandwidth_consumed_bytes(now, band.raw_, byte_count);
if (is_piece_data)
{
notify_bandwidth_consumed_bytes(now, band.piece_, byte_count);
}
if (parent_ != nullptr)
{
parent_->notify_bandwidth_consumed(dir, byte_count, is_piece_data, now);
}
}
// ---
tr_bandwidth_limits tr_bandwidth::get_limits() const
{
auto limits = tr_bandwidth_limits{};
limits.up_limit = get_desired_speed(TR_UP);
limits.down_limit = get_desired_speed(TR_DOWN);
limits.up_limited = is_limited(TR_UP);
limits.down_limited = is_limited(TR_DOWN);
return limits;
}
void tr_bandwidth::set_limits(tr_bandwidth_limits const& limits)
{
set_desired_speed(TR_UP, limits.up_limit);
set_desired_speed(TR_DOWN, limits.down_limit);
set_limited(TR_UP, limits.up_limited);
set_limited(TR_DOWN, limits.down_limited);
}