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authorNick Mathewson <nickm@torproject.org>2017-07-12 12:23:33 -0400
committerNick Mathewson <nickm@torproject.org>2017-07-27 16:28:59 -0400
commit250c88014d81fcd4406359d44c9f3f3432844a2f (patch)
tree2a56693f0703f21ea7fe2a6265fb671c8c17655b
parent0ae0b5aa4136fe6df7863c8a5b7d239d519b7393 (diff)
downloadtor-250c88014d81fcd4406359d44c9f3f3432844a2f.tar.gz
tor-250c88014d81fcd4406359d44c9f3f3432844a2f.zip
Always start with one additional worker thread
Now that half the threads are permissive and half are strict, we need to make sure we have at least two threads, so that we'll have at least one of each kind.
-rw-r--r--changes/more-threads3
-rw-r--r--src/or/cpuworker.c9
2 files changed, 11 insertions, 1 deletions
diff --git a/changes/more-threads b/changes/more-threads
new file mode 100644
index 0000000000..eae88b70fd
--- /dev/null
+++ b/changes/more-threads
@@ -0,0 +1,3 @@
+ o Minor features (relay, performance):
+ - Always start relays with at least two worker threads, to prevent
+ priority inversion on slow tasks. Part of the fix for bug 22883.
diff --git a/src/or/cpuworker.c b/src/or/cpuworker.c
index ad99af64c0..8d71483f81 100644
--- a/src/or/cpuworker.c
+++ b/src/or/cpuworker.c
@@ -89,7 +89,14 @@ cpu_init(void)
event_add(reply_event, NULL);
}
if (!threadpool) {
- threadpool = threadpool_new(get_num_cpus(get_options()),
+ /*
+ In our threadpool implementation, half the threads are permissive and
+ half are strict (when it comes to running lower-priority tasks). So we
+ always make sure we have at least two threads, so that there will be at
+ least one thread of each kind.
+ */
+ const int n_threads = get_num_cpus(get_options()) + 1;
+ threadpool = threadpool_new(n_threads,
replyqueue,
worker_state_new,
worker_state_free,