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Make qp-trie write transactions more lightweight

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This commit is contained in:
Tony Finch
2023-04-19 16:01:35 +01:00
parent 6892e463bf
commit 3f7ec89937
2 changed files with 55 additions and 34 deletions
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lib/dns/qp.c
+54 -33
View File
@@ -73,8 +73,15 @@ static atomic_uint_fast64_t rollback_time;
#define LOG_STATS(...) \
isc_log_write(dns_lctx, DNS_LOGCATEGORY_DATABASE, DNS_LOGMODULE_QP, \
ISC_LOG_DEBUG(1), __VA_ARGS__)
#define LOG_SIZES(qp, time) \
LOG_STATS("%s(%" PRIu64 " ns) chunk %u max %u leaf %u" \
" live %u used %u free %u hold %u", \
__func__, time, (qp)->chunk_count, (qp)->chunk_max, \
(qp)->leaf_count, (qp)->used_count - (qp)->free_count, \
(qp)->used_count, (qp)->free_count, (qp)->hold_count)
#else
#define LOG_STATS(...)
#define LOG_SIZES(...)
#endif
#if DNS_QP_TRACE
@@ -406,6 +413,7 @@ chunk_alloc(dns_qp_t *qp, qp_chunk_t chunk, qp_weight_t size) {
qp->base->ptr[chunk] = chunk_get_raw(qp);
qp->usage[chunk] = (qp_usage_t){ .exists = true, .used = size };
qp->used_count += size;
qp->chunk_count += 1;
qp->bump = chunk;
qp->fender = 0;
@@ -560,6 +568,7 @@ chunk_discount(dns_qp_t *qp, qp_chunk_t chunk) {
INSIST(qp->free_count >= qp->usage[chunk].free);
qp->used_count -= qp->usage[chunk].used;
qp->free_count -= qp->usage[chunk].free;
qp->chunk_count -= 1;
}
}
@@ -615,9 +624,7 @@ recycle(dns_qp_t *qp) {
if (free > 0) {
LOG_STATS("qp recycle" PRItime "free %u chunks", time, free);
LOG_STATS("qp recycle leaf %u live %u used %u free %u hold %u",
qp->leaf_count, qp->used_count - qp->free_count,
qp->used_count, qp->free_count, qp->hold_count);
LOG_SIZES(qp, time);
}
}
@@ -628,21 +635,42 @@ recycle(dns_qp_t *qp) {
static bool
defer_chunk_reclamation(dns_qp_t *qp, isc_qsbr_phase_t phase) {
unsigned int reclaim = 0;
unsigned int free = 0;
isc_nanosecs_t start = isc_time_monotonic();
for (qp_chunk_t chunk = 0; chunk < qp->chunk_max; chunk++) {
if (chunk != qp->bump && chunk_usage(qp, chunk) == 0 &&
qp->usage[chunk].exists && qp->usage[chunk].immutable &&
qp->usage[chunk].phase == 0)
qp->usage[chunk].exists)
{
chunk_discount(qp, chunk);
qp->usage[chunk].phase = phase;
reclaim++;
if (!qp->usage[chunk].immutable) {
/* clean up empty mutable chunks right now */
chunk_free(qp, chunk);
free++;
} else if (qp->usage[chunk].phase == 0) {
/*
* defer cleanup of empty immutable chunks
* that are not already scheduled for cleanup
*/
chunk_discount(qp, chunk);
qp->usage[chunk].phase = phase;
reclaim++;
}
}
}
isc_nanosecs_t time = isc_time_monotonic() - start;
atomic_fetch_add_relaxed(&recycle_time, time);
if (free > 0) {
LOG_STATS("qp defer" PRItime "free %u chunks", time, free);
}
if (reclaim > 0) {
LOG_STATS("qp will reclaim %u chunks in phase %u", reclaim,
phase);
LOG_STATS("qp defer" PRItime "%u chunks in phase %u", time,
reclaim, phase);
}
if (free > 0 || reclaim > 0) {
LOG_SIZES(qp, time);
}
return (reclaim > 0);
@@ -679,9 +707,7 @@ reclaim_chunks(dns_qp_t *qp, isc_qsbr_phase_t phase) {
if (free > 0) {
LOG_STATS("qp reclaim" PRItime "phase %u free %u chunks", time,
phase, free);
LOG_STATS("qp reclaim leaf %u live %u used %u free %u hold %u",
qp->leaf_count, qp->used_count - qp->free_count,
qp->used_count, qp->free_count, qp->hold_count);
LOG_SIZES(qp, time);
}
return (more);
@@ -765,10 +791,7 @@ marksweep_chunks(dns_qpmulti_t *multi) {
if (free > 0) {
LOG_STATS("qp marksweep" PRItime "free %u chunks", time, free);
LOG_STATS(
"qp marksweep leaf %u live %u used %u free %u hold %u",
qpw->leaf_count, qpw->used_count - qpw->free_count,
qpw->used_count, qpw->free_count, qpw->hold_count);
LOG_SIZES(qpw, time);
}
}
@@ -874,9 +897,7 @@ compact_recursive(dns_qp_t *qp, qp_node_t *parent) {
static void
compact(dns_qp_t *qp) {
LOG_STATS("qp compact before leaf %u live %u used %u free %u hold %u",
qp->leaf_count, qp->used_count - qp->free_count,
qp->used_count, qp->free_count, qp->hold_count);
LOG_SIZES(qp, 0LU);
isc_nanosecs_t start = isc_time_monotonic();
@@ -892,10 +913,7 @@ compact(dns_qp_t *qp) {
isc_nanosecs_t time = isc_time_monotonic() - start;
atomic_fetch_add_relaxed(&compact_time, time);
LOG_STATS("qp compact" PRItime
"leaf %u live %u used %u free %u hold %u",
time, qp->leaf_count, qp->used_count - qp->free_count,
qp->used_count, qp->free_count, qp->hold_count);
LOG_SIZES(qp, time);
}
void
@@ -1182,16 +1200,19 @@ dns_qpmulti_commit(dns_qpmulti_t *multi, dns_qp_t **qptp) {
/* reader_open() below has the matching atomic_load_acquire() */
atomic_store_release(&multi->reader, reader); /* COMMIT */
/* clean up what we can right now */
/*
* We don't use AUTOGC here because it is for use when we can only
* recycle mutable chunks; in this case we are (or, after a grace
* period, we will be) able to recycle immutable chunks, and NEEDGC
* takes account of immutable as well as mutable chunks.
*/
if (qp->transaction_mode == QP_UPDATE || QP_NEEDGC(qp)) {
recycle(qp);
}
/* the reclamation phase must be sampled after the commit */
isc_qsbr_phase_t phase = isc_qsbr_phase(multi->loopmgr);
if (defer_chunk_reclamation(qp, phase)) {
ISC_ASTACK_ADD(qsbr_work, multi, cleanup);
isc_qsbr_activate(multi->loopmgr, phase);
/* the reclamation phase must be sampled after the commit */
isc_qsbr_phase_t phase = isc_qsbr_phase(multi->loopmgr);
if (defer_chunk_reclamation(qp, phase)) {
ISC_ASTACK_ADD(qsbr_work, multi, cleanup);
isc_qsbr_activate(multi->loopmgr, phase);
}
}
*qptp = NULL;
lib/dns/qp_p.h
+1 -1
View File
@@ -489,7 +489,7 @@ struct dns_qp {
/*% array of per-chunk allocation counters */
qp_usage_t *usage;
/*% number of slots in `chunk` and `usage` arrays */
qp_chunk_t chunk_max;
qp_chunk_t chunk_max, chunk_count;
/*% which chunk is used for allocations */
qp_chunk_t bump;
/*% nodes in the `bump` chunk below `fender` are read only [MT] */