Restrict total parallel DNS resolutions
A/B tests suggest that large numbers of parallel
resolutions may cause the DNS failure rate
(re: ratio of "host not found" to "found") to
rise. To stay safely away from that threshold,
this change lowers the maximum parallel resolutions
to 8, and restricts the speculative resolutions
to 3.
We are also running A/B tests which will look at the
impact of modulating either of these values.
BUG=3041
r=eroman
Review URL: http://codereview.chromium.org/4111004
git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64369 0039d316-1c4b-4281-b951-d872f2087c98
diff --git a/chrome/browser/net/predictor.h b/chrome/browser/net/predictor.h
index e6363ad..f735cb4 100644
--- a/chrome/browser/net/predictor.h
+++ b/chrome/browser/net/predictor.h
@@ -263,7 +263,10 @@
// When true, we don't make new lookup requests.
bool shutdown_;
- // The number of concurrent lookups currently allowed.
+ // The number of concurrent speculative lookups currently allowed to be sent
+ // to the resolver. Any additional lookups will be queued to avoid exceeding
+ // this value. The queue is a priority queue that will accelerate
+ // sub-resource speculation, and retard resolutions suggested by page scans.
const size_t max_concurrent_dns_lookups_;
// The maximum queueing delay that is acceptable before we enter congestion
