+++ /dev/null
-============================================
-BlueStore Bufferbloat Mitigation Using CoDel
-============================================
-
-
-Introduction
-------------
-Bufferbloat happens when a frontend buffer too much data to a backend.
-This can introduce latency spikes to the backend and compromise the
-request schedulability of the frontend.
-
-BlueStore has the bufferbloat problem due to its large queue. All
-write requests are submitted immediately to BlueStore to achieve high
-performance. However, this can compromise request schedulability in OSD.
-As a solution, the CoDel algorithm is implemented in the BlueStore as
-an admission control system to control the amount of transaction
-submitted to BlueStore. This mechanism will negatively impact the
-throughput of BlueStore. However, a tradeoff parameter has been introduced
-to control BlueStore throughput loss versus BlueStore latency decrease.
-
-Configurations
---------------
-CoDel can be enabled using "*bluestore_codel*" config. The other important
-config that needs to be set is "*bluestore_codel_throughput_latency_tradeoff*".
-This config adjust the tradeoff between BlueStore throughput loss and
-BlueStore latency decrease. This parameter defines the amount of throughput
-loss in MB/s for one ms decrease in BlueStore latency. For example, a value
-of 5 means that we are willing to lose maximum of 5 MB/s of throughput for
-every 1 ms decrease in BlueStore latency.
-
-Experiments
------------
-For measuring the impact of BlueStore CoDel on BlueStore, we measured the
-transaction latency inside the BlueStore (BlueStore latency) and BlueStore
-throughput. We compared this measurements with measurements from Vanilla BlueStore.
-These experiments shows that:
-
-1. The BlueStore CoDel can decrease the BlueStore latency by small and controllable
-impact on throughput.
-2. The BlueStore CoDel can react to workload changes to keep the desired tradeoff
-between latency and throughput.
+++ /dev/null
-overrides:
- thrashosds:
- bdev_inject_crash: 2
- bdev_inject_crash_probability: .5
- ceph:
- fs: xfs
- conf:
- osd:
- osd objectstore: bluestore
- bluestore block size: 96636764160
- debug bluestore: 20
- debug bluefs: 20
- debug rocksdb: 10
- bluestore fsck on mount: true
- bluestore allocator: bitmap
- # lower the full ratios since we can fill up a 100gb osd so quickly
- mon osd full ratio: .9
- mon osd backfillfull_ratio: .85
- mon osd nearfull ratio: .8
- osd failsafe full ratio: .95
- # this doesn't work with failures bc the log writes are not atomic across the two backends
- # bluestore bluefs env mirror: true
- bdev enable discard: true
- bdev async discard: true
- bluestore codel: true
- ceph-deploy:
- fs: xfs
- bluestore: yes
- conf:
- osd:
- osd objectstore: bluestore
- bluestore block size: 96636764160
- debug bluestore: 20
- debug bluefs: 20
- debug rocksdb: 10
- bluestore fsck on mount: true
- # lower the full ratios since we can fill up a 100gb osd so quickly
- mon osd full ratio: .9
- mon osd backfillfull_ratio: .85
- mon osd nearfull ratio: .8
- osd failsafe full ratio: .95
- bdev enable discard: true
- bdev async discard: true
- bluestore codel: true
-
default: 0
services:
- mgr
-- name: bluestore_codel
- type: bool
- level: advanced
- desc: enable/disable bluestore SlowFastCodel
- default: false
- with_legacy: true
-- name: bluestore_codel_throughput_latency_tradeoff
- type: float
- level: advanced
- desc: adjust the tradeoff between throughput and bluestore latency in SlowFastCodel
- long_desc: This parameter defines the amount of throughput loss (MB/s) for one ms
- decrease in bluestore latency. (a value of 5 means that we are willing to lose
- maximum of 5 MB/s of throughput for every 1 ms decrease in bluestore latency)
- default: 5
- with_legacy: true
-- name: bluestore_codel_initial_target_latency
- type: float
- level: advanced
- desc: initial target latency for SlowFastCodel in ms
- default: 5.0
- with_legacy: true
-- name: bluestore_codel_slow_interval
- type: float
- level: advanced
- desc: the interval of slow loop in SlowFastCodel in ms (this parameter should be larger that 'bluestore_codel_fast_interval')
- default: 500.0
- with_legacy: true
-- name: bluestore_codel_fast_interval
- type: float
- level: advanced
- desc: the interval of the fast loop in SlowFastCodel in ms
- default: 50.0
- with_legacy: true
-- name: bluestore_codel_min_target_latency
- type: float
- level: advanced
- desc: the minimum possible target latency in SlowFastCodel in ms
- default: 1.0
- with_legacy: true
-- name: bluestore_codel_max_target_latency
- type: float
- level: advanced
- desc: the maximum possible target latency in SlowFastCodel in ms
- default: 1000.0
- with_legacy: true
-- name: bluestore_codel_initial_budget_bytes
- type: size
- level: advanced
- desc: the initial bluestore throttle budget in SlowFastCodel
- default: 100_K
- with_legacy: true
-- name: bluestore_codel_min_budget_bytes
- type: size
- level: advanced
- desc: the minimum bluestore throttle budget in SlowFastCodel
- default: 100_K
- with_legacy: true
-- name: bluestore_codel_budget_increment_bytes
- type: size
- level: advanced
- desc: the increment size for opening the bluestore throttle in SlowFastCodel
- default: 10_K
- with_legacy: true
-- name: bluestore_codel_regression_history_size
- type: int
- level: advanced
- desc: number of the slow interval throughput and latency samples that SlowFastCodel keeps for regression
- default: 100
- with_legacy: true
+++ /dev/null
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-
-#pragma once
-
-#include <iostream>
-#include <vector>
-#include <cmath>
-#include <boost/numeric/ublas/matrix.hpp>
-
-#define Z_P 2.33 // z score for 99th percentile
-
-
-namespace ceph {
- /***
- * Calculate the inverse of a 2x2 matrix.
- * @param matrix<double>& m, an square 2x2 matrix
- * @return the inverse of the m (m^-1)
- */
- static boost::numeric::ublas::matrix<double>
- matrix_inverse(boost::numeric::ublas::matrix<double> &m) {
- assert(m.size1() == m.size2() &&
- "Can only calculate the inverse of square matrices");
- assert(m.size1() == 2 && m.size2() == 2 && "Only for 2x2 matrices");
- boost::numeric::ublas::matrix<double> m_inverse(2, 2);
- const double a = m(0, 0);
- const double b = m(0, 1);
- const double c = m(1, 0);
- const double d = m(1, 1);
- const double determinant = 1.0 / ((a * d) - (b * c));
- m_inverse(0, 0) = d * determinant;
- m_inverse(0, 1) = -b * determinant;
- m_inverse(1, 0) = -c * determinant;
- m_inverse(1, 1) = a * determinant;
- return m_inverse;
- }
-
- /***
- * Find a logarithmic function in form of "y = a + b * ln(x)" which fits
- * the given points (x_values and y_values).
- * @param std::vector<double> x_values, x values for sample points
- * @param std::vector<double> y_values, y values for sample points
- * @param double theta[2], holds the a and b as output (theta[0] = a and theta[1] = b)
- */
- static void regression(
- const std::vector<double> &x_values,
- const std::vector<double> &y_values,
- double theta[2]) {
- assert(x_values.size() == y_values.size() &&
- "x and y values vectors should have a same size.");
- const int n = x_values.size();
-
- boost::numeric::ublas::matrix<double> y_m(n, 1);
- for (int i = 0; i < n; i++) {
- y_m(i, 0) = y_values[i];
- }
-
- boost::numeric::ublas::scalar_matrix<double> sm(n, 2, 1);
- boost::numeric::ublas::matrix<double> x_new_m(sm);
- for (int i = 0; i < n; i++) {
- x_new_m(i, 0) = 1;
- x_new_m(i, 1) = std::log(x_values[i]);
- }
- boost::numeric::ublas::matrix<double> x_new_trans_m = boost::numeric::ublas::trans(
- x_new_m);
- boost::numeric::ublas::matrix<double> x_new_trans_dot_x_new_m = boost::numeric::ublas::prod(
- x_new_trans_m, x_new_m);
- boost::numeric::ublas::matrix<double> temp_1_m = matrix_inverse(
- x_new_trans_dot_x_new_m);
- boost::numeric::ublas::matrix<double> temp_2_m = boost::numeric::ublas::prod(
- x_new_trans_m, y_m);
- boost::numeric::ublas::matrix<double> theta_m = boost::numeric::ublas::prod(
- temp_1_m, temp_2_m);
- theta[0] = theta_m(0, 0);
- theta[1] = theta_m(1, 0);
- }
-
- /***
- * Finds the x location on a fitted logarithmic curve on sample points where
- * the slope is equal to target_slope
- * @param x_values, x values for sample points
- * @param y_values, y values for sample points
- * @param target_slope, the slope that we are looking for
- * @return the x location where the slope of the curve is target_slope
- */
- static double find_slope_on_curve(
- const std::vector<double> &x_values,
- const std::vector<double> &y_values,
- double target_slope) {
- assert(x_values.size() == y_values.size() &&
- "x and y values vectors should have a same size.");
- assert(target_slope != 0 &&
- "The target slope of zero will result to a inf x, try a nonzero value.");
- assert(target_slope >= 0 &&
- "The target slope for a logarithmic function should be positive.");
- double theta[2]; // theta[0] + theta[1] * ln(x)
- regression(x_values, y_values,
- theta); // find the logarithmic function using regression
- double target_x = theta[1] /
- target_slope; // find the x where the slope is close to target_slope
- return target_x;
- }
-
- /***
- * Finds the mu and std parameters of the lognormal distribution from its mode
- * and x boundaries.
- * @param mode, the mode of the distribution.
- * @param min_x, x lower boundary of distribution (zero percentile)
- * @param max_x, x upper boundary of distribution (99th percentile)
- * @param params, holds the calculated distribution parameters (mu and std) as
- * output (params[0] = mu and params[1] = std)
- */
- static void
- find_log_normal_dist_params(double mode, double min_x, double max_x,
- double params[2]) {
- assert(min_x < max_x && "The min_x should be smaller than max_x");
- assert(mode >= min_x && mode < max_x &&
- "The mode should be between min_x and max_x");
- double max_x_normalized = max_x - min_x;
- double mode_normalized = mode - min_x;
- double std_dev = (-Z_P + std::sqrt(
- Z_P * Z_P + 4 * std::log(max_x_normalized) -
- 4 * std::log(mode_normalized))) / 2;
- double mu = std::log(max_x_normalized) - Z_P * std_dev;
- params[0] = mu;
- params[1] = std_dev;
- }
-}
${PROJECT_SOURCE_DIR}/src/os/bluestore/BlueStore.cc
${PROJECT_SOURCE_DIR}/src/os/bluestore/simple_bitmap.cc
${PROJECT_SOURCE_DIR}/src/os/bluestore/bluestore_types.cc
- ${PROJECT_SOURCE_DIR}/src/os/bluestore/BlueStoreSlowFastCoDel.cc
${PROJECT_SOURCE_DIR}/src/os/bluestore/fastbmap_allocator_impl.cc
${PROJECT_SOURCE_DIR}/src/os/bluestore/FreelistManager.cc
${PROJECT_SOURCE_DIR}/src/os/bluestore/HybridAllocator.cc
bluestore/BlueStore.cc
bluestore/simple_bitmap.cc
bluestore/bluestore_types.cc
- bluestore/BlueStoreSlowFastCoDel.cc
bluestore/fastbmap_allocator_impl.cc
bluestore/FreelistManager.cc
bluestore/StupidAllocator.cc
_init_logger();
cct->_conf.add_observer(this);
set_cache_shards(1);
- if ( cct->_conf->bluestore_codel) {
- codel = std::make_unique<BlueStoreSlowFastCoDel>(
- cct, [this](int64_t x) mutable {
- this->throttle.reset_kv_throttle_max(x);
- },
- [this]() mutable {
- return this->throttle.get_kv_throttle_current();
- });
- }
}
BlueStore::~BlueStore()
"bluestore_warn_on_no_per_pool_omap",
"bluestore_warn_on_no_per_pg_omap",
"bluestore_max_defer_interval",
- "bluestore_codel",
- "bluestore_codel_slow_interval",
- "bluestore_codel_fast_interval",
- "bluestore_codel_initial_target_latency",
- "bluestore_codel_min_target_latency",
- "bluestore_codel_max_target_latency",
- "bluestore_codel_throughput_latency_tradeoff",
- "bluestore_codel_initial_budget_bytes",
- "bluestore_codel_min_budget_bytes",
- "bluestore_codel_budget_increment_bytes",
- "bluestore_codel_regression_history_size",
NULL
};
return KEYS;
changed.count("bluestore_throttle_deferred_bytes") ||
changed.count("bluestore_throttle_trace_rate")) {
throttle.reset_throttle(conf);
- if (codel) {
- codel->reset_bluestore_budget();
- }
}
if (changed.count("bluestore_max_defer_interval")) {
if (bdev) {
changed.count("osd_memory_expected_fragmentation")) {
_update_osd_memory_options();
}
- if (changed.count("bluestore_codel") ||
- changed.count("bluestore_codel_slow_interval") ||
- changed.count("bluestore_codel_fast_interval") ||
- changed.count("bluestore_codel_initial_target_latency") ||
- changed.count("bluestore_codel_min_target_latency") ||
- changed.count("bluestore_codel_max_target_latency") ||
- changed.count("bluestore_codel_throughput_latency_tradeoff") ||
- changed.count("bluestore_codel_initial_budget_bytes") ||
- changed.count("bluestore_codel_min_budget_bytes") ||
- changed.count("bluestore_codel_budget_increment_bytes") ||
- changed.count("bluestore_codel_regression_history_size")) {
- if (codel) {
- codel->on_config_changed(cct);
- }
- }
}
void BlueStore::_set_compression()
case TransContext::STATE_KV_DONE:
throttle.log_state_latency(*txc, logger, l_bluestore_state_kv_done_lat);
- if (codel) {
- codel->update_from_txc_info(txc->txc_state_proc_start, txc->bytes);
- }
if (txc->deferred_txn) {
txc->set_state(TransContext::STATE_DEFERRED_QUEUED);
_deferred_queue(txc);
logger->inc(l_bluestore_txc);
// execute (start)
- txc->txc_state_proc_start = mono_clock::now();
_txc_state_proc(txc);
if (bdev->is_smr()) {
#include "bluestore_types.h"
#include "BlueFS.h"
#include "common/EventTrace.h"
-#include "BlueStoreSlowFastCoDel.h"
#ifdef WITH_BLKIN
#include "common/zipkin_trace.h"
uint64_t seq = 0;
ceph::mono_clock::time_point start;
ceph::mono_clock::time_point last_stamp;
- ceph::mono_clock::time_point txc_state_proc_start;
uint64_t last_nid = 0; ///< if non-zero, highest new nid we allocated
uint64_t last_blobid = 0; ///< if non-zero, highest new blobid we allocated
trace_period_mcs = rate > 0 ? floor((1/rate) * 1000000.0) : 0;
#endif
}
- int64_t get_kv_throttle_current() {
- return throttle_bytes.get_current();
- }
- void reset_kv_throttle_max(int64_t m) {
- throttle_bytes.reset_max(m);
- }
} throttle;
- std::unique_ptr<BlueStoreSlowFastCoDel> codel;
-
typedef boost::intrusive::list<
TransContext,
boost::intrusive::member_hook<
+++ /dev/null
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-
-#include "BlueStoreSlowFastCoDel.h"
-
-#include "common/regression_utils.h"
-
-BlueStoreSlowFastCoDel::BlueStoreSlowFastCoDel(
- CephContext *_cct,
- std::function<void(int64_t)> _bluestore_budget_reset_callback,
- std::function<int64_t()> _get_kv_throttle_current) :
- fast_timer(_cct, fast_timer_lock),
- slow_timer(_cct, slow_timer_lock),
- bluestore_budget_reset_callback(_bluestore_budget_reset_callback),
- get_kv_throttle_current(_get_kv_throttle_current) {
- on_config_changed(_cct);
-}
-
-BlueStoreSlowFastCoDel::~BlueStoreSlowFastCoDel() {
- {
- std::lock_guard l1{fast_timer_lock};
- fast_timer.cancel_all_events();
- fast_timer.shutdown();
- }
-
- {
- std::lock_guard l2{slow_timer_lock};
- slow_timer.cancel_all_events();
- slow_timer.shutdown();
- }
-
- regression_throughput_history.clear();
- regression_target_latency_history.clear();
-}
-
-void BlueStoreSlowFastCoDel::update_from_txc_info(
- ceph::mono_clock::time_point txc_start_time,
- uint64_t txc_bytes) {
- std::lock_guard l(register_lock);
- ceph::mono_clock::time_point now = ceph::mono_clock::now();
- int64_t latency = std::chrono::nanoseconds(now - txc_start_time).count();
-
- if (activated && max_queue_length < get_kv_throttle_current()) {
- max_queue_length = get_kv_throttle_current();
- }
- if (min_latency == INITIAL_LATENCY_VALUE || latency < min_latency) {
- min_latency = latency;
- }
- slow_interval_txc_cnt++;
- slow_interval_registered_bytes += txc_bytes;
-}
-
-void BlueStoreSlowFastCoDel::on_min_latency_violation() {
- if (target_latency > 0) {
- double diff = (double) (target_latency - min_latency);
- auto error_ratio = std::abs(diff) / min_latency;
- if (error_ratio > 0.5) {
- error_ratio = 0.5;
- }
- bluestore_budget = std::max(bluestore_budget * (1 - error_ratio),
- min_bluestore_budget * 1.0);
- }
-}
-
-void BlueStoreSlowFastCoDel::on_no_violation() {
- if (bluestore_budget < max_queue_length * 1.5) {
- bluestore_budget = bluestore_budget + bluestore_budget_increment;
- }
-}
-
-void BlueStoreSlowFastCoDel::on_config_changed(CephContext *cct) {
- {
- std::lock_guard l(register_lock);
-
- activated = cct->_conf->bluestore_codel;
- target_slope = cct->_conf->bluestore_codel_throughput_latency_tradeoff;
- slow_interval = ((int64_t) cct->_conf->bluestore_codel_slow_interval) *
- 1000 * 1000;
- initial_fast_interval = ((int64_t)
- cct->_conf->bluestore_codel_fast_interval) * 1000 * 1000;
- initial_target_latency = ((int64_t)
- cct->_conf->bluestore_codel_initial_target_latency) * 1000 * 1000;
- min_target_latency = ((int64_t)
- cct->_conf->bluestore_codel_min_target_latency) * 1000 * 1000;
- max_target_latency = ((int64_t)
- cct->_conf->bluestore_codel_max_target_latency) * 1000 * 1000;
- initial_bluestore_budget = cct->_conf->bluestore_codel_initial_budget_bytes;
- min_bluestore_budget = cct->_conf->bluestore_codel_min_budget_bytes;
- bluestore_budget_increment =
- cct->_conf->bluestore_codel_budget_increment_bytes;
- regression_history_size =
- cct->_conf->bluestore_codel_regression_history_size;
-
- bluestore_budget = initial_bluestore_budget;
- min_bluestore_budget = initial_bluestore_budget;
- max_queue_length = min_bluestore_budget;
- fast_interval = initial_fast_interval;
- target_latency = initial_target_latency;
- min_latency = INITIAL_LATENCY_VALUE;
- slow_interval_registered_bytes = 0;
- regression_throughput_history.clear();
- regression_target_latency_history.clear();
- slow_interval_start = ceph::mono_clock::zero();
- }
-
- {
- std::lock_guard l1{fast_timer_lock};
- fast_timer.cancel_all_events();
- fast_timer.init();
- }
- _fast_interval_process();
- {
- std::lock_guard l2{slow_timer_lock};
- slow_timer.cancel_all_events();
- slow_timer.init();
- }
- _slow_interval_process();
-}
-
-void BlueStoreSlowFastCoDel::reset_bluestore_budget() {
- if (activated) {
- bluestore_budget = std::max(min_bluestore_budget, bluestore_budget);
- bluestore_budget_reset_callback(bluestore_budget);
- }
-}
-
-void BlueStoreSlowFastCoDel::_fast_interval_process() {
- std::lock_guard l(register_lock);
- if (target_latency != INITIAL_LATENCY_VALUE &&
- min_latency != INITIAL_LATENCY_VALUE) {
- if (activated) {
- if (_check_latency_violation()) {
- // min latency violation
- violation_count++;
- _update_interval();
- on_min_latency_violation(); // handle the violation
- } else {
- // no latency violation
- violation_count = 0;
- fast_interval = initial_fast_interval;
- on_no_violation();
- }
- bluestore_budget = std::max(min_bluestore_budget, bluestore_budget);
- bluestore_budget_reset_callback(bluestore_budget);
- }
-
- // reset interval
- min_latency = INITIAL_LATENCY_VALUE;
-
- on_fast_interval_finished();
- }
-
- auto codel_ctx = new LambdaContext(
- [this](int r) {
- _fast_interval_process();
- });
- auto interval_duration = std::chrono::nanoseconds(fast_interval);
- fast_timer.add_event_after(interval_duration, codel_ctx);
-}
-
-void BlueStoreSlowFastCoDel::_slow_interval_process() {
- std::lock_guard l(register_lock);
- ceph::mono_clock::time_point now = ceph::mono_clock::now();
- if (activated && !ceph::mono_clock::is_zero(slow_interval_start)
- && slow_interval_txc_cnt > 0) {
- double time_sec = nanosec_to_sec(
- std::chrono::nanoseconds(now - slow_interval_start).count());
-
- double slow_interval_throughput =
- (slow_interval_registered_bytes * 1.0) / time_sec;
- slow_interval_throughput = slow_interval_throughput / (1024.0 * 1024.0);
- regression_target_latency_history.push_back(
- nanosec_to_millisec(target_latency));
- regression_throughput_history.push_back(slow_interval_throughput);
- if (regression_target_latency_history.size() > regression_history_size) {
- regression_target_latency_history.erase(
- regression_target_latency_history.begin());
- regression_throughput_history.erase(
- regression_throughput_history.begin());
- }
- std::vector<double> targets;
- std::vector<double> throughputs;
- double target_ms = nanosec_to_millisec(initial_target_latency);
- // If there is sufficient number of points, use the regression to find the
- // target_ms. Otherwise, target_ms will be initial_target_latency
- if (regression_target_latency_history.size() >= regression_history_size) {
- target_ms = ceph::find_slope_on_curve(
- regression_target_latency_history,
- regression_throughput_history,
- target_slope);
- }
-
- target_latency_without_noise = millisec_to_nanosec(target_ms);
- target_latency_without_noise = std::max(target_latency_without_noise,
- min_target_latency);
- target_latency_without_noise = std::min(target_latency_without_noise,
- max_target_latency);
- target_ms = nanosec_to_millisec(target_latency_without_noise);
-
- // add log_normal noise
- unsigned seed = std::chrono::system_clock::now().time_since_epoch().count();
- std::default_random_engine generator(seed);
- double dist_params[2];
- double rnd_std_dev = 5;
- ceph::find_log_normal_dist_params(
- target_ms,
- nanosec_to_millisec(min_target_latency),
- target_ms * rnd_std_dev,
- dist_params);
- std::lognormal_distribution<double> distribution(dist_params[0],
- dist_params[1]);
-
- target_latency = millisec_to_nanosec(distribution(generator));
- target_latency += min_target_latency;
-
- if (target_latency < millisec_to_nanosec(target_ms)) {
- std::uniform_real_distribution<> distr(0, 0.5);
- target_latency = target_latency +
- (target_latency - millisec_to_nanosec(target_ms)) *
- distr(generator);
- }
-
- if (target_latency != INITIAL_LATENCY_VALUE) {
- target_latency = std::max(target_latency, min_target_latency);
- target_latency = std::min(target_latency, max_target_latency);
- }
-
- on_slow_interval_finished();
- }
-
- slow_interval_start = ceph::mono_clock::now();
- slow_interval_registered_bytes = 0;
- slow_interval_txc_cnt = 0;
- max_queue_length = min_bluestore_budget;
-
- auto codel_ctx = new LambdaContext(
- [this](int r) {
- _slow_interval_process();
- });
- auto interval_duration = std::chrono::nanoseconds(slow_interval);
- slow_timer.add_event_after(interval_duration, codel_ctx);
-}
-
-
-/**
-* check if the min latency violate the target
-* @return true if min latency violate the target, false otherwise
-*/
-bool BlueStoreSlowFastCoDel::_check_latency_violation() {
- if (target_latency != INITIAL_LATENCY_VALUE &&
- min_latency != INITIAL_LATENCY_VALUE) {
- if (min_latency > target_latency) {
- return true;
- }
- }
- return false;
-}
-
-void BlueStoreSlowFastCoDel::_update_interval() {
- auto sqrt = (int) std::round(std::sqrt(violation_count));
- fast_interval = initial_fast_interval / sqrt;
- if (fast_interval <= 0) {
- fast_interval = 1000;
- }
-}
-
-int64_t BlueStoreSlowFastCoDel::get_bluestore_budget() {
- return bluestore_budget;
-}
-
-int64_t BlueStoreSlowFastCoDel::get_target_latency() {
- return target_latency;
-}
+++ /dev/null
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-
-#pragma once
-
-#include <iostream>
-
-#include "include/Context.h"
-#include "common/Timer.h"
-#include "common/ceph_time.h"
-
-class BlueStoreSlowFastCoDel {
-public:
- BlueStoreSlowFastCoDel(
- CephContext *_cct,
- std::function<void(int64_t)> _bluestore_budget_reset_callback,
- std::function<int64_t()> _get_kv_throttle_current);
-
- virtual ~BlueStoreSlowFastCoDel();
-
- void on_config_changed(CephContext *cct);
-
- void reset_bluestore_budget();
-
- void update_from_txc_info(
- ceph::mono_clock::time_point txc_start_time,
- uint64_t txc_bytes);
-
- int64_t get_bluestore_budget();
-
- int64_t get_target_latency();
-
- bool is_activated();
-
-protected:
- static const int64_t INITIAL_LATENCY_VALUE = -1;
-
- /* config values */
- // Config value 'bluestore_codel',true if SlowFastCodel is activated
- bool activated = false;
- // Config value 'bluestore_codel_fast_interval', Initial interval for fast loop
- int64_t initial_fast_interval = INITIAL_LATENCY_VALUE;
- // Config value 'bluestore_codel_initial_target_latency', Initial target latency
- // to start the algorithm
- int64_t initial_target_latency = INITIAL_LATENCY_VALUE;
- // Config value 'bluestore_codel_slow_interval', the interval for the slow loop
- int64_t slow_interval = INITIAL_LATENCY_VALUE;
- // Config value 'bluestore_codel_min_target_latency', min possible value for target
- int64_t min_target_latency = INITIAL_LATENCY_VALUE; // in ns
- // Config value 'bluestore_codel_max_target_latency', max possible value for target
- int64_t max_target_latency = INITIAL_LATENCY_VALUE; // in ns
- // Config value 'bluestore_codel_throughput_latency_tradeoff', define the
- // tradeoff between throughput and latency (MB/s loss for every 1ms latency drop)
- double target_slope = 5;
- // Config value 'bluestore_codel_regression_history_size', regression history size
- int64_t regression_history_size = 100;
- // Config value 'bluestore_codel_min_budget_bytes', the minimum bluestore
- // throttle budget
- int64_t min_bluestore_budget = 102400;
- // Config value 'bluestore_codel_initial_budget_bytes', the initial bluestore
- // throttle budget
- int64_t initial_bluestore_budget = 102400;
- // Config value 'bluestore_codel_budget_increment_bytes', the increment size
- // for opening the bluestore throttle
- int64_t bluestore_budget_increment = 102400;
-
- /* internal state variables */
- // current interval for the fast loop
- int64_t fast_interval = INITIAL_LATENCY_VALUE;
- // current target latency that fast loop is using
- int64_t target_latency = INITIAL_LATENCY_VALUE;
- int64_t target_latency_without_noise = INITIAL_LATENCY_VALUE;
- // min latency in the current fast interval
- int64_t min_latency = INITIAL_LATENCY_VALUE;
- int64_t violation_count = 0;
- ceph::mutex fast_timer_lock = ceph::make_mutex("CoDel::fast_timer_lock");
- ceph::mutex slow_timer_lock = ceph::make_mutex("CoDel::slow_timer_lock");
- ceph::mutex register_lock = ceph::make_mutex("CoDel::register_lock");
- SafeTimer fast_timer; // fast loop timer
- SafeTimer slow_timer; // slow loop timer
- // marks the start of the current slow interval
- ceph::mono_clock::time_point slow_interval_start = ceph::mono_clock::zero();
- // amount of bytes that has been processed in current slow interval
- int64_t slow_interval_registered_bytes = 0;
- // number of transactions that has been processed in current slow interval
- int64_t slow_interval_txc_cnt = 0;
- // target latency history for regression
- std::vector<double> regression_target_latency_history;
- // throughput history for regression
- std::vector<double> regression_throughput_history;
- int64_t bluestore_budget = 102400; // current bluestore throttle budget
- // maximum amount of inflight data in current slow interval
- int64_t max_queue_length = 102400;
- std::function<void(int64_t)> bluestore_budget_reset_callback;
- std::function<int64_t(void)> get_kv_throttle_current;
-
- void on_min_latency_violation();
-
- void on_no_violation();
-
- virtual void on_fast_interval_finished() {}
-
- virtual void on_slow_interval_finished() {}
-
-private:
-
- bool _check_latency_violation();
-
- void _update_interval();
-
- void _fast_interval_process();
-
- void _slow_interval_process();
-
- template<typename T>
- double millisec_to_nanosec(T ms) {
- return ms * 1000.0 * 1000.0;
- }
-
- template<typename T>
- double nanosec_to_millisec(T ns) {
- return ns / (1000.0 * 1000.0);
- }
-
- template<typename T>
- double nanosec_to_sec(T ns) {
- return ns / (1000.0 * 1000.0 * 1000.0);
- }
-};
add_ceph_unittest(unittest_random)
target_link_libraries(unittest_random Boost::random)
-# unittest_regression_utils
-add_executable(unittest_regression_utils test_regression_utils.cc)
-add_ceph_unittest(unittest_regression_utils)
-target_link_libraries(unittest_regression_utils ceph-common global)
-
# unittest_throttle
add_executable(unittest_throttle
Throttle.cc
+++ /dev/null
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-// vim: ts=8 sw=2 smarttab
-
-#include <gtest/gtest.h>
-#include <vector>
-#include <cmath>
-#include "common/regression_utils.h"
-#include <boost/numeric/ublas/matrix.hpp>
-#include <boost/numeric/ublas/io.hpp>
-
-using namespace boost::numeric::ublas;
-
-std::vector<double> generate_rand_vector(int size, int max_value) {
- std::srand(std::time(0));
- std::vector<double> rand_vec;
- for (int i = 0; i < size; i++) {
- double rand_value = std::rand() % max_value;
- rand_vec.push_back(rand_value);
- }
- return rand_vec;
-}
-
-matrix<double> generate_rand_matrix(int size1, int size2, int max_value) {
- std::srand(std::time(0));
- matrix<double> rand_m(size1, size2);
- for (int i = 0; i < size1; i++) {
- for (int j = 0; j < size2; j++) {
- double rand_value = std::rand() % max_value;
- rand_m(i, j) = rand_value;
- }
- }
- return rand_m;
-}
-
-std::vector<double> exp_vector(std::vector<double> x) {
- std::vector<double> exp_vec;
- for (int i = 0; i < x.size(); i++) {
- exp_vec.push_back(std::exp(x[i]));
- }
- return exp_vec;
-}
-
-bool is_almost_equal(double x1, double x2, double precision) {
- if (std::abs(x1 - x2) < precision) {
- return true;
- }
- return false;
-}
-
-TEST(matrix_op, matrix_inverse) {
- int matrix_size = 2; // has to be 2x2
- matrix<double> random_square_m = generate_rand_matrix(matrix_size, matrix_size, 1000);
- matrix<double> random_square_m_inv = ceph::matrix_inverse(random_square_m);
- // the inverse matrix should have the same size
- ASSERT_EQ(random_square_m_inv.size1(), random_square_m.size1());
- ASSERT_EQ(random_square_m_inv.size2(), random_square_m.size2());
- matrix<double> matrix_prod = prod(random_square_m, random_square_m_inv);
- // the product should be an identity matrix
- for ( int i = 0; i < matrix_prod.size1(); i++){
- for (int j = 0; j < matrix_prod.size2(); j++){
- if (i == j) {
- ASSERT_TRUE(is_almost_equal(matrix_prod(i, j), 1, 1e-9)); // i == j -> 1
- } else {
- ASSERT_TRUE(is_almost_equal(matrix_prod(i, j), 0, 1e-9)); // i <> j -> 0
- }
- }
- }
-}
-
-TEST(regression, log_regression) {
- // y = ln(x)
- std::vector<double> y = generate_rand_vector(200, 100);
- std::vector<double> x = exp_vector(y);
-
- double theta[2]; // y = theta[0] + theta[1] * ln(x)
- ceph::regression(x, y, theta);
- ASSERT_TRUE(is_almost_equal(theta[0], 0, 1e-9)); // theta[0] = 0
- ASSERT_TRUE(is_almost_equal(theta[1], 1, 1e-9)); // theta[1] = 1
-}
-
-TEST(regression, find_slope_location) {
- // y = ln(x)
- std::vector<double> y = generate_rand_vector(200, 100);
- std::vector<double> x = exp_vector(y);
-
- double target_slope = 5;
- double x_target = ceph::find_slope_on_curve(x, y, target_slope);
- ASSERT_TRUE(is_almost_equal(x_target, 0.2, 1e-9)); // y'(0.2) = 5
-}
add_ceph_unittest(unittest_lfnindex)
target_link_libraries(unittest_lfnindex os global)
-add_subdirectory(bluestore)
+++ /dev/null
-# unittest_slow_fast_codel
-add_executable(unittest_slow_fast_codel
- TestBlueStoreSlowFastCoDel.cc
- )
-add_ceph_unittest(unittest_slow_fast_codel)
-target_link_libraries(unittest_slow_fast_codel
- rados_test_stub
- librados
- global
- radostest-cxx
- GTest::GTest
- ceph-common
- os
- global
- )
+++ /dev/null
-// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
-// vim: ts=8 sw=2 smarttab
-
-#include <filesystem>
-#include <iostream>
-#include <unistd.h>
-#include <mutex>
-#include <cmath>
-#include <vector>
-#include <condition_variable>
-#include <cmath>
-#include <cstdlib>
-
-#include "gtest/gtest.h"
-#include "include/Context.h"
-
-#include "common/ceph_time.h"
-#include "os/bluestore/BlueStoreSlowFastCoDel.h"
-
-
-static int64_t milliseconds_to_nanoseconds(int64_t ms) {
- return ms * 1000.0 * 1000.0;
-}
-
-static double nanoseconds_to_milliseconds(int64_t ms) {
- return ms / (1000.0 * 1000.0);
-}
-
-class BlueStoreSlowFastCoDelMock : public BlueStoreSlowFastCoDel {
-public:
- BlueStoreSlowFastCoDelMock(
- CephContext *_cct,
- std::function<void(int64_t)> _bluestore_budget_reset_callback,
- std::function<int64_t()> _get_kv_throttle_current,
- std::mutex &_iteration_mutex,
- std::condition_variable &_iteration_cond,
- int64_t _target_latency,
- int64_t _fast_interval,
- int64_t _slow_interval,
- double _target_slope
- ) : BlueStoreSlowFastCoDel(_cct, _bluestore_budget_reset_callback,
- _get_kv_throttle_current),
- iteration_mutex(_iteration_mutex), iteration_cond(_iteration_cond),
- test_target_latency(_target_latency), test_fast_interval(_fast_interval),
- test_slow_interval(_slow_interval), test_target_slope(_target_slope) {
- init_test();
- }
-
- void init_test() {
- std::lock_guard l(register_lock);
- activated = true;
- target_slope = test_target_slope;
- slow_interval = test_slow_interval;
- initial_fast_interval = test_fast_interval;
- min_target_latency = milliseconds_to_nanoseconds(1);
- initial_target_latency = test_target_latency;
- max_target_latency = milliseconds_to_nanoseconds(500);
- initial_bluestore_budget = 100 * 1024;
- min_bluestore_budget = 10 * 1024;
- bluestore_budget_increment = 1024;
- regression_history_size = 5;
- bluestore_budget = initial_bluestore_budget;
- min_bluestore_budget = initial_bluestore_budget;
- max_queue_length = min_bluestore_budget;
- fast_interval = initial_fast_interval;
- target_latency = initial_target_latency;
- min_latency = INITIAL_LATENCY_VALUE;
- slow_interval_registered_bytes = 0;
- regression_throughput_history.clear();
- regression_target_latency_history.clear();
- slow_interval_start = ceph::mono_clock::zero();
- }
-
- std::vector <int64_t> target_latency_vector;
-
-protected:
- std::mutex &iteration_mutex;
- std::condition_variable &iteration_cond;
- int64_t test_target_latency;
- int64_t test_fast_interval;
- int64_t test_slow_interval;
- double test_target_slope;
-
- void on_fast_interval_finished() override {
- std::unique_lock <std::mutex> locker(iteration_mutex);
- iteration_cond.notify_one();
- }
-
- void on_slow_interval_finished() override {
- target_latency_vector.push_back(target_latency);
- }
-};
-
-class TestSlowFastCoDel : public ::testing::Test {
-public:
- CephContext *ceph_context = nullptr;
- BlueStoreSlowFastCoDelMock *slow_fast_codel = nullptr;
- int64_t test_throttle_budget = 0;
- std::mutex iteration_mutex;
- std::condition_variable iteration_cond;
- int64_t target_latency = milliseconds_to_nanoseconds(50);
- int64_t fast_interval = milliseconds_to_nanoseconds(100);
- int64_t slow_interval = milliseconds_to_nanoseconds(400);
- double target_slope = 1;
-
- std::vector <int64_t> target_latency_vector;
- std::vector <int64_t> txc_size_vector;
-
- TestSlowFastCoDel() {}
-
- ~TestSlowFastCoDel() {}
-
- static void SetUpTestCase() {}
-
- static void TearDownTestCase() {}
-
- void SetUp() override {
- ceph_context = (new CephContext(CEPH_ENTITY_TYPE_ANY))->get();
- }
-
- void create_bluestore_slow_fast_codel() {
- slow_fast_codel = new BlueStoreSlowFastCoDelMock(
- ceph_context,
- [this](int64_t x) mutable {
- this->test_throttle_budget = x;
- },
- [this]() mutable {
- return this->test_throttle_budget;
- },
- iteration_mutex,
- iteration_cond,
- target_latency,
- fast_interval,
- slow_interval,
- target_slope);
- }
-
- void TearDown() override {
- if (slow_fast_codel)
- delete slow_fast_codel;
- }
-
- void test_codel() {
- int64_t max_iterations = 50;
- int iteration_timeout = 1; // 1 sec
- int txc_num = 4;
- for (int iteration = 0; iteration < max_iterations; iteration++) {
- std::unique_lock <std::mutex> locker(iteration_mutex);
- bool violation = iteration % 2 == 1;
- auto budget_tmp = test_throttle_budget;
- auto target = slow_fast_codel->get_target_latency();
- double target_throughput =
- (target_slope * nanoseconds_to_milliseconds(target_latency)) *
- std::log(nanoseconds_to_milliseconds(target) * 1.0);
- int64_t txc_size =
- (nanoseconds_to_milliseconds(slow_interval) *
- target_throughput) /
- (1000 * txc_num * (slow_interval / fast_interval));
- txc_size *= 1024 * 1024;
- txc_size_vector.push_back(txc_size);
- target_latency_vector.push_back(target);
- for (int i = 0; i < txc_num; i++) {
- auto time = ceph::mono_clock::now();
- if (violation) {
- int rand_ms = std::rand() % 1000 + 1000;
- int64_t time_diff = milliseconds_to_nanoseconds(rand_ms);
- time = time - std::chrono::nanoseconds(target + time_diff);
- }
- slow_fast_codel->update_from_txc_info(time, txc_size);
- }
- if (iteration_cond.wait_for(
- locker, std::chrono::seconds(iteration_timeout)) ==
- std::cv_status::timeout) {
- ASSERT_TRUE(false) << "Test timeout.";
- return;
- }
- if (violation) {
- ASSERT_LT(test_throttle_budget, budget_tmp);
- } else {
- ASSERT_GT(test_throttle_budget, budget_tmp);
- }
- }
-
- ASSERT_TRUE(slow_fast_codel->target_latency_vector.size() > 0);
- }
-};
-
-TEST_F(TestSlowFastCoDel, test1) {
- create_bluestore_slow_fast_codel();
- test_codel();
-}
projects / ceph.git / commitdiff