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"
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() {
pthread_mutex_destroy(&throttle_mut);
pthread_mutex_destroy(&dummy_throttle_mut);
pthread_cond_destroy(&dummy_throttle_cond);
pthread_cond_destroy(&throttle_wokeup_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)c0->target_size);
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) {
c0->target_size = size;
}
void mergeManager::update_progress(mergeStats * s, int delta) {
s->delta += delta;
if((!delta) || s->delta > UPDATE_PROGRESS_DELTA) {
if(delta) {
rwlc_writelock(ltable->header_mut);
s->delta = 0;
if(!s->need_tick) { s->need_tick = 1; }
}
if(s->merge_level != 0) {
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;
}
}
if(s->merge_level != 2) {
if(s->mergeable_size) {
s->out_progress = ((double)s->current_size) / (double)s->target_size;
} else {
s->out_progress = 0.0;
}
}
s->current_size = s->base_size + s->bytes_out - s->bytes_in_large;
struct timeval now;
gettimeofday(&now, 0);
double elapsed_delta = tv_to_double(&now) - ts_to_double(&s->last_tick);
s->lifetime_elapsed += elapsed_delta;
s->lifetime_consumed += s->bytes_in_small_delta;
double decay = 0.9999; // XXX set this in some principled way. Surely, it should depend on tick_length (once that's working...)
s->window_elapsed = (decay * s->window_elapsed) + elapsed_delta;
s->window_consumed = (decay * s->window_consumed) + s->bytes_in_small_delta;
double_to_ts(&s->last_tick, tv_to_double(&now));
s->bytes_in_small_delta = 0;
s->bps = s->window_consumed / s->window_elapsed;
if(delta) 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(bytes_in_small_delta)
*/
void mergeManager::tick(mergeStats * s, bool block, bool force) {
#define PRINT_SKIP 100
if(force || s->need_tick) {
if(block) {
rwlc_writelock(ltable->header_mut);
while(sleeping[s->merge_level]) {
rwlc_cond_wait(&throttle_wokeup_cond, ltable->header_mut);
}
int64_t overshoot = 0;
int64_t overshoot2 = 0;
int64_t raw_overshoot = 0;
/* model the effect of linux + stasis' write caches; at the end
of this merge, we need to force up to FORCE_INTERVAL bytes
after we think we're done writing the next component. */
double skew = 0.0;
int64_t overshoot_fudge = (int64_t)((s->out_progress-skew) * ((double)FORCE_INTERVAL)/(1.0-skew));
/* model the effect of amortizing this computation: we could
become this much more overshot if we don't act now. */
int64_t overshoot_fudge2 = UPDATE_PROGRESS_DELTA;
/* multiply by 2 for good measure. These are 'soft' walls, and
still let writes trickle through. Once we've exausted the
fudge factors, we'll hit a hard wall, and stop writes
entirely, so it's better to start thottling too early than
too late. */
overshoot_fudge *= 2;
overshoot_fudge2 *= 2;
int spin = 0;
double total_sleep = 0.0;
do{
overshoot = 0;
overshoot2 = 0;
raw_overshoot = 0;
double bps;
// This needs to be here (and not in update_progress), since the other guy's in_progress changes while we sleep.
if(s->merge_level == 0) {
if(!(c1->active && c0->mergeable_size)) { overshoot_fudge = 0; overshoot_fudge2 = 0; }
raw_overshoot = (int64_t)(((double)c0->target_size) * (c0->out_progress - c1->in_progress));
overshoot = raw_overshoot + overshoot_fudge;
overshoot2 = raw_overshoot + overshoot_fudge2;
bps = c1->bps;
} else if (s->merge_level == 1) {
if(!(c2->active && c1->mergeable_size)) { overshoot_fudge = 0; overshoot_fudge2 = 0; }
raw_overshoot = (int64_t)(((double)c1->target_size) * (c1->out_progress - c2->in_progress));
overshoot = raw_overshoot + overshoot_fudge;
overshoot2 = raw_overshoot + overshoot_fudge2;
bps = c2->bps;
}
//#define PP_THREAD_INFO
#ifdef PP_THREAD_INFO
printf("\nMerge thread %d %6f %6f Overshoot: raw=%lld, d=%lld eff=%lld Throttle min(1, %6f) spin %d, total_sleep %6.3f\n", s->merge_level, c0_out_progress, c0_c1_in_progress, raw_overshoot, overshoot_fudge, overshoot, -1.0, spin, total_sleep);
#endif
if(s->print_skipped == PRINT_SKIP) {
pretty_print(stdout);
s->print_skipped = 0;
} else {
s->print_skipped++;
}
bool one_threshold = (overshoot > 0 || overshoot2 > 0) || (raw_overshoot > 0);
bool two_threshold = (overshoot > 0 || overshoot2 > 0) && (raw_overshoot > 0);
if(one_threshold && (two_threshold || total_sleep < 0.01)) {
// throttle
// it took "elapsed" seconds to process "tick_length_bytes" mb
double sleeptime = 2.0 * fmax((double)overshoot,(double)overshoot2) / bps;
struct timespec sleep_until;
double max_c0_sleep = 0.1;
double min_c0_sleep = 0.05;
double max_c1_sleep = 0.5;
double min_c1_sleep = 0.1;
double max_sleep = s->merge_level == 0 ? max_c0_sleep : max_c1_sleep;
double min_sleep = s->merge_level == 0 ? min_c0_sleep : min_c1_sleep;
if(sleeptime < min_sleep) { sleeptime = min_sleep; }
if(sleeptime > max_sleep) { sleeptime = max_sleep; }
spin ++;
total_sleep += sleeptime;
if((spin > 40) || (total_sleep > (max_sleep * 20.0))) {
// if(spin > 20 || s->merge_level == 0) {
printf("\nMerge thread %d Overshoot: raw=%lld, d=%lld eff=%lld Throttle min(1, %6f) spin %d, total_sleep %6.3f\n", s->merge_level, raw_overshoot, overshoot_fudge, overshoot, sleeptime, spin, total_sleep);
// }
}
struct timeval now;
gettimeofday(&now, 0);
double_to_ts(&sleep_until, sleeptime + tv_to_double(&now));
sleeping[s->merge_level] = true;
rwlc_cond_timedwait(&dummy_throttle_cond, ltable->header_mut, &sleep_until);
sleeping[s->merge_level] = false;
pthread_cond_broadcast(&throttle_wokeup_cond);
gettimeofday(&now, 0);
if(s->merge_level == 0) { update_progress(c1, 0); }
if(s->merge_level == 1) { update_progress(c2, 0); }
} else {
if(overshoot > 0 || overshoot2 > 0) {
s->need_tick ++;
if(s->need_tick > 100) { printf("need tick %d\n", s->need_tick); }
} else {
s->need_tick = 0;
}
break;
}
} while(1);
rwlc_unlock(ltable->header_mut);
} else {
if(s->print_skipped == PRINT_SKIP) {
if(!force) rwlc_writelock(ltable->header_mut);
pretty_print(stdout);
if(!force) rwlc_unlock(ltable->header_mut);
s->print_skipped = 0;
} else {
s->print_skipped++;
}
}
}
}
void mergeManager::read_tuple_from_small_component(int merge_level, datatuple * tup) {
if(tup) {
mergeStats * s = get_merge_stats(merge_level);
(s->num_tuples_in_small)++;
(s->bytes_in_small_delta) += tup->byte_length();
(s->bytes_in_small) += tup->byte_length();
update_progress(s, tup->byte_length());
tick(s, true);
}
}
void mergeManager::read_tuple_from_large_component(int merge_level, datatuple * tup) {
if(tup) {
mergeStats * s = get_merge_stats(merge_level);
s->num_tuples_in_large++;
s->bytes_in_large += tup->byte_length();
// tick(s, false); // would be no-op; we just reduced current_size.
update_progress(s, tup->byte_length());
tick(s,false);
}
}
void mergeManager::wrote_tuple(int merge_level, datatuple * tup) {
mergeStats * s = get_merge_stats(merge_level);
(s->num_tuples_out)++;
(s->bytes_out) += tup->byte_length();
// XXX this just updates stat's current size, and (perhaps) does a pretty print. It should not need a mutex.
// update_progress(s, tup->byte_length());
// tick(s, false);
}
void mergeManager::finished_merge(int merge_level) {
update_progress(get_merge_stats(merge_level), 0);
tick(get_merge_stats(merge_level), false, true); // XXX what does this do???
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);
}
gettimeofday(&get_merge_stats(merge_level)->done, 0);
update_progress(get_merge_stats(merge_level), 0);
}
mergeManager::mergeManager(logtable<datatuple> *ltable):
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)) {
pthread_mutex_init(&throttle_mut, 0);
pthread_mutex_init(&dummy_throttle_mut, 0);
pthread_cond_init(&dummy_throttle_cond, 0);
pthread_cond_init(&throttle_wokeup_cond, 0);
struct timeval tv;
gettimeofday(&tv, 0);
sleeping[0] = false;
sleeping[1] = false;
sleeping[2] = false;
double_to_ts(&c0->last_tick, tv_to_double(&tv));
double_to_ts(&c1->last_tick, tv_to_double(&tv));
double_to_ts(&c2->last_tick, tv_to_double(&tv));
}
void mergeManager::pretty_print(FILE * out) {
pageid_t mb = 1024 * 1024;
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();
}
double c0_out_progress = 100.0 * c0->current_size / c0->target_size;
double c0_c1_in_progress = 100.0 * (c1->bytes_in_large + c1->bytes_in_small) / (c0->mergeable_size + c1->base_size);
double c0_c1_out_progress = 100.0 * c1->current_size / c1->target_size;
double c1_c2_progress = 100.0 * (c2->bytes_in_large + c2->bytes_in_small) / (c1->mergeable_size + c2->base_size);
assert((!c1->active) || (c0_c1_in_progress >= -1 && c0_c1_in_progress < 102));
assert((!c2->active) || (c1_c2_progress >= -1 && c1_c2_progress < 102));
fprintf(out,"[merge progress MB/s window (lifetime)]: app [%s %6lldMB ~ %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" : "---", (uint64_t)(c0->lifetime_consumed / mb), c0_out_progress, c0->lifetime_elapsed, c0->window_consumed/(((double)mb)*c0->window_elapsed), c0->lifetime_consumed/(((double)mb)*c0->lifetime_elapsed),
have_c0 ? "C0" : "..",
have_c0m ? "C0'" : "...",
c1->active ? "RUN" : "---", c0_c1_in_progress, c0_c1_out_progress, c1->window_consumed/(((double)mb)*c1->window_elapsed), c1->lifetime_consumed/(((double)mb)*c1->lifetime_elapsed),
have_c1 ? "C1" : "..",
have_c1m ? "C1'" : "...",
c2->active ? "RUN" : "---", c1_c2_progress, c2->window_consumed/(((double)mb)*c2->window_elapsed), c2->lifetime_consumed/(((double)mb)*c2->lifetime_elapsed),
have_c2 ? "C2" : "..");
//#define PP_SIZES
#ifdef PP_SIZES
fprintf(out, "[size in small/large, out, mergeable] C0 %4lld %4lld %4lld %4lld %4lld %4lld ",
c0->target_size/mb, c0->current_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 ",
c1->target_size/mb, c1->current_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 ",
/*----*/ c2->current_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);
fprintf(out, "\r");
}