From 501e2d4ea3c5d685fec8b34618a79964fe2945a7 Mon Sep 17 00:00:00 2001 From: "eroman@chromium.org" Date: Wed, 30 Jan 2013 22:30:49 +0000 Subject: Improve performance of proxy resolver by tracing DNS dependencies. This replaces the multi-threaded V8 proxy resolver implementation, with a faster single-threaded one. The single-threaded version uses some magic to avoid blocking on DNS dependencies, so it is able to handle more parallel requests than the multi-threaded one. Design document: https://docs.google.com/a/chromium.org/document/d/16Ij5OcVnR3s0MH4Z5XkhI9VTPoMJdaBn9rKreAmGOdE/edit This has the benefit of reducing the number of threads that Chrome uses for PAC evaluation, while at the same time speeding up proxy resolving for PAC scripts that do DNS resolving (due to better parallelism). I ran a benchmark to evaluate the effectiveness of this new approach. The benchmark simulates loading the http://www.newyorktimes.com webpage with slow DNS (where each DNS resolve takes 2 seconds), and a maximum DNS resolver parallelism of 10 requests. This webpage resolves the proxy for 221 URLs, across 40 unique hostnames. - Proxy resolving using the old multithreaded code took 24.076 seconds [*] - Proxy resolving using the new code took 8.011 seconds [*] - Without a PAC script, resolving the DNS took 8.003 seconds The new proxy resolving times (8.011s) are much closer to the theoretical best (8.003s)! [*] The PAC script I used for the test was a fairly complex script 20kb (a version of google's corp PAC script modified to always call dnsResolve(host)). I will be adding histograms in a follow-up CL, to measure how often requests need to be restarted, or fall-back to synchronous mode. BUG=119151 Review URL: https://codereview.chromium.org/11885009 git-svn-id: svn://svn.chromium.org/chrome/trunk/src@179714 0039d316-1c4b-4281-b951-d872f2087c98 --- net/proxy/proxy_resolver_mac.h | 3 --- 1 file changed, 3 deletions(-) (limited to 'net/proxy/proxy_resolver_mac.h') diff --git a/net/proxy/proxy_resolver_mac.h b/net/proxy/proxy_resolver_mac.h index 2aafce2..d791a7d 100644 --- a/net/proxy/proxy_resolver_mac.h +++ b/net/proxy/proxy_resolver_mac.h @@ -31,9 +31,6 @@ class NET_EXPORT ProxyResolverMac : public ProxyResolver { virtual LoadState GetLoadState(RequestHandle request) const OVERRIDE; - virtual LoadState GetLoadStateThreadSafe( - RequestHandle request) const OVERRIDE; - virtual void CancelSetPacScript() OVERRIDE; virtual int SetPacScript( -- cgit v1.1