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| author | Michael Cahill <michael.cahill@mongodb.com> | 2015-11-25 00:01:19 +1100 |
|---|---|---|
| committer | Michael Cahill <michael.cahill@mongodb.com> | 2015-11-25 00:01:19 +1100 |
| commit | 122382417b1223fbcac1220fc0b863a373bddd69 (patch) | |
| tree | 2ffb4ad4ce1ee5750b10582ee856de4b20bab7bd /src | |
| parent | 0a52a80a39fc47145fb755d792792ae820b266ed (diff) | |
| download | mongo-122382417b1223fbcac1220fc0b863a373bddd69.tar.gz | |
WT-2337 Avoid yields if we race allocating transaction IDs.
It had a major perf impact on parallel populate workloads including YCSB.
Diffstat (limited to 'src')
| -rw-r--r-- | src/include/txn.i | 14 |
1 files changed, 9 insertions, 5 deletions
diff --git a/src/include/txn.i b/src/include/txn.i index f19cf259174..ef9d5a273cf 100644 --- a/src/include/txn.i +++ b/src/include/txn.i @@ -323,6 +323,7 @@ __wt_txn_id_alloc(WT_SESSION_IMPL *session, bool publish) { WT_TXN_GLOBAL *txn_global; uint64_t id; + u_int i; txn_global = &S2C(session)->txn_global; @@ -353,14 +354,17 @@ __wt_txn_id_alloc(WT_SESSION_IMPL *session, bool publish) if (publish) { session->txn.id = id; - WT_PUBLISH(WT_SESSION_TXN_STATE(session)->id, id); + WT_SESSION_TXN_STATE(session)->id = id; } - while (txn_global->current != id || - !__wt_atomic_casv64(&txn_global->current, id, id + 1)) - __wt_yield(); + for (i = 0; txn_global->current != id; i++) + if (i < 100) + WT_PAUSE(); + else + __wt_yield(); - return (id); + WT_PUBLISH(txn_global->current, id + 1); + return (id); } /* |