stasis-bLSM/mergeManager.cpp

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/*
* mergeManager.cpp
*
* Created on: May 19, 2010
* Author: sears
*/
#include "mergeManager.h"
#include "mergeStats.h"
#include "logstore.h"
#include "math.h"
#include "time.h"
#include <stasis/transactional.h>
#undef try
#undef end
mergeStats* mergeManager:: get_merge_stats(int mergeLevel) {
if (mergeLevel == 0) {
return c0;
} else if (mergeLevel == 1) {
return c1;
} else if(mergeLevel == 2) {
return c2;
} else {
abort();
}
}
mergeManager::~mergeManager() {
still_running = false;
pthread_cond_signal(&pp_cond);
pthread_join(pp_thread, 0);
pthread_cond_destroy(&pp_cond);
delete c0;
delete c1;
delete c2;
}
void mergeManager::new_merge(int mergeLevel) {
mergeStats * s = get_merge_stats(mergeLevel);
if(s->merge_level == 0) {
// target_size was set during startup
} else if(s->merge_level == 1) {
assert(c0->target_size);
c1->target_size = (pageid_t)(*ltable->R() * (double)ltable->mean_c0_run_length);
assert(c1->target_size);
} else if(s->merge_level == 2) {
// target_size is infinity...
} else { abort(); }
s->new_merge2();
}
void mergeManager::set_c0_size(int64_t size) {
assert(size);
c0->target_size = size;
}
void mergeManager::update_progress(mergeStats * s, int delta) {
s->delta += delta;
if((!delta) || s->delta > UPDATE_PROGRESS_DELTA) {
rwlc_writelock(ltable->header_mut);
if(delta) {
s->delta = 0;
if(!s->need_tick) { s->need_tick = 1; }
}
if(s->merge_level == 2) {
if(s->active) {
s->in_progress = ((double)(s->bytes_in_large + s->bytes_in_small)) / (double)(get_merge_stats(s->merge_level-1)->mergeable_size + s->base_size);
} else {
s->in_progress = 0;
}
} else if(s->merge_level == 1) { // C0-C1 merge (c0 is continuously growing...)
if(s->active) {
s->in_progress = ((double)(s->bytes_in_large+s->bytes_in_small)) / (double)(s->base_size+ltable->mean_c0_run_length);
} else {
s->in_progress = 0;
}
}
if(s->merge_level == 0) {
s->current_size = ltable->tree_bytes; // we need to track the number of bytes consumed by the merger; this data is not present in s, so fall back on ltable's aggregate.
} else {
s->current_size = s->base_size + s->bytes_out - s->bytes_in_large;
}
s->out_progress = ((double)s->current_size) / ((s->merge_level == 0 ) ? (double)ltable->mean_c0_run_length : (double)s->target_size);
if(c2->active && c1->mergeable_size) {
c1_c2_delta = c1->out_progress - c2->in_progress;
} else {
c1_c2_delta = -0.02; // We try to keep this number between -0.05 and -0.01.
}
#if EXTENDED_STATS
struct timeval now;
gettimeofday(&now, 0);
double stats_elapsed_delta = tv_to_double(&now) - ts_to_double(&s->stats_last_tick);
if(stats_elapsed_delta < 0.0000001) { stats_elapsed_delta = 0.0000001; }
s->stats_lifetime_elapsed += stats_elapsed_delta;
s->stats_lifetime_consumed += s->stats_bytes_in_small_delta;
double stats_tau = 60.0; // number of seconds to look back for window computation. (this is the expected mean residence time in an exponential decay model, so the units are not so intuitive...)
double stats_decay = exp((0.0-stats_elapsed_delta)/stats_tau);
double_to_ts(&s->stats_last_tick, tv_to_double(&now));
double stats_window_bps = ((double)s->stats_bytes_in_small_delta) / (double)stats_elapsed_delta;
s->stats_bps = (1.0-stats_decay) * stats_window_bps + stats_decay * s->stats_bps;
s->stats_bytes_in_small_delta = 0;
#endif
rwlc_unlock(ltable->header_mut);
}
}
/**
* This function is invoked periodically by the merge threads. It updates mergeManager's statistics, and applies
* backpressure as necessary.
*
* Here is the backpressure algorithm.
*
* We want to maintain these two invariants:
* - for each byte consumed by the app->c0 threads, a byte is consumed by the c0->c1 merge thread.
* - for each byte consumed by the c0->c1 thread, the c1->c2 thread consumes a byte
*
* More concretely (and taking into account varying values of R):
* capacity(C_i) - current_size(C_i) >= size(C_i_mergeable) - bytes_consumed_by_next_merger
*
* where:
* capacity c0 = c0_queue_size
* capacity c1 = c1_queue_size
*
* current_size(c_i) = sum(bytes_out_delta) - sum(bytes_in_large_delta)
*
* bytes_consumed_by_merger = sum(stats_bytes_in_small_delta)
*/
void mergeManager::tick(mergeStats * s) {
if(s->merge_level == 1) { // apply backpressure based on merge progress.
if(s->need_tick) {
s->need_tick = 0;
// Only apply back pressure if next thread is not waiting on us.
rwlc_readlock(ltable->header_mut);
if(c1->mergeable_size && c2->active) {
if(c1_c2_delta > -0.01) {
DEBUG("Input is too far ahead. Delta is %f\n", c1_c2_delta);
double delta = c1_c2_delta;
rwlc_unlock(ltable->header_mut);
delta += 0.01; // delta > 0;
double slp = 0.001 + delta;
struct timespec sleeptime;
DEBUG("\ndisk sleeping %0.6f tree_megabytes %0.3f\n", slp, ((double)ltable->tree_bytes)/(1024.0*1024.0));
double_to_ts(&sleeptime,slp);
nanosleep(&sleeptime, 0);
update_progress(s, 0);
s->need_tick = 1;
} else {
rwlc_unlock(ltable->header_mut);
}
} else {
rwlc_unlock(ltable->header_mut);
}
}
} else if(s->merge_level == 0) {
// Simple backpressure algorithm based on how full C0 is.
// Is C0 bigger than is allowed?
while(ltable->tree_bytes > ltable->max_c0_size) { // can't use s->current_size, since this is the thread that maintains that number...
printf("\nMEMORY OVERRUN!!!! SLEEP!!!!\n");
struct timespec ts;
double_to_ts(&ts, 0.1);
nanosleep(&ts, 0);
}
// Linear backpressure model
s->current_size = ltable->tree_bytes;
s->out_progress = ((double)ltable->tree_bytes)/((double)ltable->max_c0_size);
double delta = ((double)ltable->tree_bytes)/(0.9*(double)ltable->max_c0_size); // 0 <= delta <= 1.111...
delta -= 1.0;
if(delta > 0.00005) {
double slp = 0.001 + 5.0 * delta; //0.0015 < slp < 1.112111..
DEBUG("\nmem sleeping %0.6f tree_megabytes %0.3f\n", slp, ((double)ltable->tree_bytes)/(1024.0*1024.0));
struct timespec sleeptime;
double_to_ts(&sleeptime, slp);
DEBUG("%d Sleep C %f\n", s->merge_level, slp);
nanosleep(&sleeptime, 0);
}
}
}
void mergeManager::read_tuple_from_small_component(int merge_level, datatuple * tup) {
if(tup) {
mergeStats * s = get_merge_stats(merge_level);
#if EXTENDED_STATS
(s->stats_num_tuples_in_small)++;
(s->stats_bytes_in_small_delta) += tup->byte_length();
#endif
(s->bytes_in_small) += tup->byte_length();
update_progress(s, tup->byte_length());
tick(s);
}
}
void mergeManager::read_tuple_from_large_component(int merge_level, int tuple_count, pageid_t byte_len) {
if(tuple_count) {
mergeStats * s = get_merge_stats(merge_level);
#if EXTENDED_STATS
s->stats_num_tuples_in_large += tuple_count;
#endif
s->bytes_in_large += byte_len;
update_progress(s, byte_len);
}
}
void mergeManager::wrote_tuple(int merge_level, datatuple * tup) {
mergeStats * s = get_merge_stats(merge_level);
#if EXTENDED_STATS
(s->stats_num_tuples_out)++;
#endif
(s->bytes_out) += tup->byte_length();
}
void mergeManager::finished_merge(int merge_level) {
update_progress(get_merge_stats(merge_level), 0);
get_merge_stats(merge_level)->active = false;
if(merge_level != 0) {
get_merge_stats(merge_level - 1)->mergeable_size = 0;
update_progress(get_merge_stats(merge_level-1), 0);
}
#if EXTENDED_STATS
gettimeofday(&get_merge_stats(merge_level)->stats_done, 0);
#endif
update_progress(get_merge_stats(merge_level), 0);
}
void * mergeManager::pretty_print_thread() {
pthread_mutex_t dummy_mut;
pthread_mutex_init(&dummy_mut, 0);
while(still_running) {
struct timeval tv;
gettimeofday(&tv, 0);
struct timespec ts;
double_to_ts(&ts, tv_to_double(&tv)+1.01);
pthread_cond_timedwait(&pp_cond, &dummy_mut, &ts);
if(ltable) {
rwlc_readlock(ltable->header_mut);
pretty_print(stdout);
rwlc_unlock(ltable->header_mut);
}
}
printf("\n");
return 0;
}
void * merge_manager_pretty_print_thread(void * arg) {
mergeManager * m = (mergeManager*)arg;
return m->pretty_print_thread();
}
double mergeManager::c1_c2_progress_delta() {
return c1_c2_delta;
}
void mergeManager::init_helper(void) {
struct timeval tv;
c1_c2_delta = -0.02; // XXX move this magic number somewhere. It's also in update_progress.
gettimeofday(&tv, 0);
#if EXTENDED_STATS
double_to_ts(&c0->stats_last_tick, tv_to_double(&tv));
double_to_ts(&c1->stats_last_tick, tv_to_double(&tv));
double_to_ts(&c2->stats_last_tick, tv_to_double(&tv));
#endif
still_running = true;
pthread_cond_init(&pp_cond, 0);
pthread_create(&pp_thread, 0, merge_manager_pretty_print_thread, (void*)this);
}
mergeManager::mergeManager(logtable<datatuple> *ltable):
UPDATE_PROGRESS_PERIOD(0.005),
ltable(ltable) {
c0 = new mergeStats(0, ltable ? ltable->max_c0_size : 10000000);
c1 = new mergeStats(1, (int64_t)(ltable ? ((double)(ltable->max_c0_size) * *ltable->R()) : 100000000.0) );
c2 = new mergeStats(2, 0);
init_helper();
}
mergeManager::mergeManager(logtable<datatuple> *ltable, int xid, recordid rid):
UPDATE_PROGRESS_PERIOD(0.005),
ltable(ltable) {
marshalled_header h;
Tread(xid, rid, &h);
c0 = new mergeStats(xid, h.c0);
c1 = new mergeStats(xid, h.c1);
c2 = new mergeStats(xid, h.c2);
init_helper();
}
recordid mergeManager::talloc(int xid) {
marshalled_header h;
recordid ret = Talloc(xid, sizeof(h));
h.c0 = c0->talloc(xid);
h.c1 = c1->talloc(xid);
h.c2 = c2->talloc(xid);
Tset(xid, ret, &h);
return ret;
}
void mergeManager::marshal(int xid, recordid rid) {
marshalled_header h;
Tread(xid, rid, &h);
c0->marshal(xid, h.c0);
c1->marshal(xid, h.c1);
c2->marshal(xid, h.c2);
}
void mergeManager::pretty_print(FILE * out) {
#if EXTENDED_STATS
logtable<datatuple> * lt = (logtable<datatuple>*)ltable;
bool have_c0 = false;
bool have_c0m = false;
bool have_c1 = false;
bool have_c1m = false;
bool have_c2 = false;
if(lt) {
have_c0 = NULL != lt->get_tree_c0();
have_c0m = NULL != lt->get_tree_c0_mergeable();
have_c1 = NULL != lt->get_tree_c1();
have_c1m = NULL != lt->get_tree_c1_mergeable() ;
have_c2 = NULL != lt->get_tree_c2();
}
pageid_t mb = 1024 * 1024;
fprintf(out,"[merge progress MB/s window (lifetime)]: app [%s %6lldMB ~ %3.0f%%/%3.0f%% %6.1fsec %4.1f (%4.1f)] %s %s [%s %3.0f%% ~ %3.0f%% %4.1f (%4.1f)] %s %s [%s %3.0f%% %4.1f (%4.1f)] %s ",
c0->active ? "RUN" : "---", (long long)(c0->stats_lifetime_consumed / mb), 100.0 * c0->out_progress, 100.0 * ((double)ltable->tree_bytes)/(double)ltable->max_c0_size, c0->stats_lifetime_elapsed, c0->stats_bps/((double)mb), c0->stats_lifetime_consumed/(((double)mb)*c0->stats_lifetime_elapsed),
have_c0 ? "C0" : "..",
have_c0m ? "C0'" : "...",
c1->active ? "RUN" : "---", 100.0 * c1->in_progress, 100.0 * c1->out_progress, c1->stats_bps/((double)mb), c1->stats_lifetime_consumed/(((double)mb)*c1->stats_lifetime_elapsed),
have_c1 ? "C1" : "..",
have_c1m ? "C1'" : "...",
c2->active ? "RUN" : "---", 100.0 * c2->in_progress, c2->stats_bps/((double)mb), c2->stats_lifetime_consumed/(((double)mb)*c2->stats_lifetime_elapsed),
have_c2 ? "C2" : "..");
#endif
//#define PP_SIZES
#ifdef PP_SIZES
{
pageid_t mb = 1024 * 1024;
fprintf(out, "[target cur base in_small in_large, out, mergeable] C0 %4lld %4lld %4lld %4lld %4lld %4lld %4lld ",
c0->target_size/mb, c0->current_size/mb, c0->base_size/mb, c0->bytes_in_small/mb,
c0->bytes_in_large/mb, c0->bytes_out/mb, c0->mergeable_size/mb);
fprintf(out, "C1 %4lld %4lld %4lld %4lld %4lld %4lld %4lld ",
c1->target_size/mb, c1->current_size/mb, c1->base_size/mb, c1->bytes_in_small/mb,
c1->bytes_in_large/mb, c1->bytes_out/mb, c1->mergeable_size/mb);
fprintf(out, "C2 ---- %4lld %4lld %4lld %4lld %4lld %4lld ",
/*----*/ c2->current_size/mb, c2->base_size/mb, c2->bytes_in_small/mb,
c2->bytes_in_large/mb, c2->bytes_out/mb, c2->mergeable_size/mb);
}
#endif
// fprintf(out, "Throttle: %6.1f%% (cur) %6.1f%% (overall) ", 100.0*(last_throttle_seconds/(last_elapsed_seconds)), 100.0*(throttle_seconds/(elapsed_seconds)));
// fprintf(out, "C0 size %4lld resident %4lld ",
// 2*c0_queueSize/mb,
// (c0->bytes_out - c0->bytes_in_large)/mb);
// fprintf(out, "C1 size %4lld resident %4lld\r",
// 2*c1_queueSize/mb,
// (c1->bytes_out - c1->bytes_in_large)/mb);
// fprintf(out, "C2 size %4lld\r",
// 2*c2_queueSize/mb);
// fprintf(out, "C1 MB/s (eff; active) %6.1f C2 MB/s %6.1f\r",
// ((double)c1_totalConsumed)/((double)c1_totalWorktime),
// ((double)c2_totalConsumed)/((double)c2_totalWorktime));
fflush(out);
#if 0 // XXX would like to bring this back somehow...
assert((!c1->active) || (c1->in_progress >= -0.01 && c1->in_progress < 1.02));
assert((!c2->active) || (c2->in_progress >= -0.01 && c2->in_progress < 1.10));
#endif
fprintf(out, "\r");
}