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verification-rate based thread scaling

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This commit is contained in:
Robert Habermeier 2016-10-04 20:09:54 +02:00
parent 2d28c703d6
commit abbf3b3c58
1 changed files with 49 additions and 40 deletions
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89
ethcore/src/verification/queue/mod.rs
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@ -18,7 +18,7 @@
//! Sorts them ready for blockchain insertion.
use std::thread::{JoinHandle, self};
use std::sync::atomic::{AtomicBool, Ordering as AtomicOrdering};
use std::sync::atomic::{AtomicBool, AtomicUsize, Ordering as AtomicOrdering};
use std::sync::{Condvar as SCondvar, Mutex as SMutex};
use util::*;
use io::*;
@ -113,7 +113,7 @@ pub struct VerificationQueue<K: Kind> {
ready_signal: Arc<QueueSignal>,
empty: Arc<SCondvar>,
processing: RwLock<HashSet<H256>>,
rolling_sample: Mutex<VecDeque<(usize, usize)>>,
ticks_since_adjustment: AtomicUsize,
max_queue_size: usize,
max_mem_use: usize,
}
@ -152,6 +152,8 @@ struct Verification<K: Kind> {
bad: Mutex<HashSet<H256>>,
more_to_verify: SMutex<()>,
empty: SMutex<()>,
verified_count: AtomicUsize,
drained: AtomicUsize,
}
impl<K: Kind> VerificationQueue<K> {
@ -164,7 +166,8 @@ impl<K: Kind> VerificationQueue<K> {
bad: Mutex::new(HashSet::new()),
more_to_verify: SMutex::new(()),
empty: SMutex::new(()),
verified_count: AtomicUsize::new(0),
drained: AtomicUsize::new(0),
});
let more_to_verify = Arc::new(SCondvar::new());
let deleting = Arc::new(AtomicBool::new(false));
@ -186,7 +189,7 @@ impl<K: Kind> VerificationQueue<K> {
deleting: deleting,
processing: RwLock::new(HashSet::new()),
empty: empty,
rolling_sample: Mutex::new(VecDeque::new()),
ticks_since_adjustment: AtomicUsize::new(0),
max_queue_size: max(config.max_queue_size, MIN_QUEUE_LIMIT),
max_mem_use: max(config.max_mem_use, MIN_MEM_LIMIT),
};
@ -248,7 +251,7 @@ impl<K: Kind> VerificationQueue<K> {
// we're next!
let mut verified = verification.verified.lock();
let mut bad = verification.bad.lock();
VerificationQueue::drain_verifying(&mut verifying, &mut verified, &mut bad);
VerificationQueue::drain_verifying(&mut verifying, &mut verified, &mut bad, &verification.verified_count);
ready.set();
}
},
@ -261,7 +264,7 @@ impl<K: Kind> VerificationQueue<K> {
verifying.retain(|e| e.hash != hash);
if verifying.front().map_or(false, |x| x.output.is_some()) {
VerificationQueue::drain_verifying(&mut verifying, &mut verified, &mut bad);
VerificationQueue::drain_verifying(&mut verifying, &mut verified, &mut bad, &verification.verified_count);
ready.set();
}
}
@ -269,7 +272,13 @@ impl<K: Kind> VerificationQueue<K> {
}
}
fn drain_verifying(verifying: &mut VecDeque<Verifying<K>>, verified: &mut VecDeque<K::Verified>, bad: &mut HashSet<H256>) {
fn drain_verifying(
verifying: &mut VecDeque<Verifying<K>>,
verified: &mut VecDeque<K::Verified>,
bad: &mut HashSet<H256>,
v_count: &AtomicUsize
) {
let start_len = verified.len();
while let Some(output) = verifying.front_mut().and_then(|x| x.output.take()) {
assert!(verifying.pop_front().is_some());
@ -279,6 +288,8 @@ impl<K: Kind> VerificationQueue<K> {
verified.push_back(output);
}
}
v_count.fetch_add(verified.len() - start_len, AtomicOrdering::AcqRel);
}
/// Clear the queue and stop verification activity.
@ -389,6 +400,8 @@ impl<K: Kind> VerificationQueue<K> {
let count = min(max, verified.len());
let result = verified.drain(..count).collect::<Vec<_>>();
self.verification.drained.fetch_add(count, AtomicOrdering::AcqRel);
self.ready_signal.reset();
if !verified.is_empty() {
self.ready_signal.set();
@ -429,53 +442,49 @@ impl<K: Kind> VerificationQueue<K> {
/// Optimise memory footprint of the heap fields, and adjust the number of threads
/// to better suit the workload.
pub fn collect_garbage(&self) {
// thresholds for adding and removing verifier threads
// these are unbalanced since having all blocks verified
// is the desirable position.
const ADD_THREAD_THRESHOLD: usize = 10;
const DEL_THREAD_THRESHOLD: usize = 20;
// number of ticks to average queue stats over
// when deciding whether to change the number of verifiers.
const SAMPLE_SIZE: usize = 5;
let (u_len, v_len) = {
let u_len = {
let mut v = self.verification.unverified.lock();
v.shrink_to_fit();
v.len()
};
const READJUSTMENT_PERIOD: usize = 5;
{
self.verification.unverified.lock().shrink_to_fit();
self.verification.verifying.lock().shrink_to_fit();
self.verification.verified.lock().shrink_to_fit();
}
let v_len = {
let mut v = self.verification.verified.lock();
v.shrink_to_fit();
v.len()
};
(u_len, v_len)
};
self.processing.write().shrink_to_fit();
let (u_len, v_len) = {
let mut sample = self.rolling_sample.lock();
sample.push_back((u_len, v_len));
if self.ticks_since_adjustment.load(AtomicOrdering::SeqCst) == READJUSTMENT_PERIOD {
self.ticks_since_adjustment.store(0, AtomicOrdering::SeqCst);
} else {
self.ticks_since_adjustment.fetch_add(1, AtomicOrdering::SeqCst);
return;
}
if sample.len() > SAMPLE_SIZE {
let _ = sample.pop_front();
}
let v_count = self.verification.verified_count.load(AtomicOrdering::Acquire);
let drained = self.verification.drained.load(AtomicOrdering::Acquire);
sample.iter().cloned().fold((0, 0), |(u_t, v_t), (u_i, v_i)| (u_t + u_i, v_t + v_i))
self.verification.verified_count.store(0, AtomicOrdering::Release);
self.verification.drained.store(0, AtomicOrdering::Release);
// compute the average rate of verification per thread and determine
// how many are necessary to match the rate of draining.
let num_verifiers = self.verifiers.lock().len();
let v_count_per = v_count as f64 / num_verifiers as f64;
let needed = if v_count < 20 {
1
} else {
(drained as f64 / v_count_per as f64).ceil() as usize
};
// more than 10x as many unverified as verified.
if v_len * ADD_THREAD_THRESHOLD < u_len {
trace!(target: "verification", "v_rate_per={}, drained={}, scaling to {} verifiers",
v_count_per, drained, needed);
for _ in num_verifiers..needed {
self.add_verifier();
}
// more than 20x as many verified as unverified.
if u_len * DEL_THREAD_THRESHOLD < v_len {
for _ in needed..num_verifiers {
self.remove_verifier();
}
}