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add overshoot2

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git-svn-id: svn+ssh://svn.corp.yahoo.com/yahoo/yrl/labs/pnuts/code/logstore@863 8dad8b1f-cf64-0410-95b6-bcf113ffbcfe
This commit is contained in:
sears 2010-06-18 23:44:48 +00:00
parent 8c35a1265a
commit 1c02dc1281
1 changed files with 29 additions and 8 deletions
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37
mergeManager.cpp
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@ -125,27 +125,44 @@ void mergeManager::tick(mergeStats * s, bool block, bool force) {
}
int64_t overshoot = 0;
int64_t overshoot2 = 0;
int64_t raw_overshoot = 0;
// int64_t overshoot_fudge = (int64_t)((s->out_progress-0.5) * 18.0 * 1024.0 * 1024.0);
// double skew = 0.5; // should be between 0 and 0.5. 0 means that there is no 'catch up' after merge commit
int64_t overshoot_fudge = UPDATE_PROGRESS_DELTA + (int64_t)(s->out_progress * ((double)FORCE_INTERVAL)); //+ (int64_t)((s->out_progress-skew) * (0.0 / (1.0-skew)) * 1024.0 * 1024.0); // should be some function of R, delta interval, and force interval. // xxx divide FORCE_INTERVAL by R?
/* 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; // should be between 0 and 0.5. 0 means that there is no 'catch up' after merge commit
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; }
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; }
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;
}
@ -159,10 +176,14 @@ void mergeManager::tick(mergeStats * s, bool block, bool force) {
} else {
s->print_skipped++;
}
if(overshoot > 0 && (raw_overshoot > 0 || total_sleep < 0.01)) {
bool one_threshold = (overshoot > 0 || overshoot2 > 0) || (raw_overshoot > 0);
bool two_threshold = (overshoot > 0 || overshoot2 > 0) && (raw_overshoot > 0);
// if(overshoot > 0 && (raw_overshoot > 0 || total_sleep < 0.01)) {
if(one_threshold && (two_threshold || total_sleep < 0.01)) {
// throttle
// it took "elapsed" seconds to process "tick_length_bytes" mb
double sleeptime = 2.0 * (double)overshoot / bps;
double sleeptime = 2.0 * fmax((double)overshoot,(double)overshoot2) / bps;
struct timespec sleep_until;
@ -197,7 +218,7 @@ void mergeManager::tick(mergeStats * s, bool block, bool force) {
if(s->merge_level == 0) { update_progress(c1, 0); }
if(s->merge_level == 1) { update_progress(c2, 0); }
} else {
if(overshoot > 0) {
if(overshoot > 0 || overshoot2 > 0) {
s->need_tick ++;
if(s->need_tick > 100) { printf("need tick %d\n", s->need_tick); }
} else {