Fix for Chrome extremely slow with Fiddler

[NiceGuyM]

Hi,
I've been a Fiddler user for a few years and it's an amazing tool so
thanks Eric for the tool and for mantaining it!
For the past couple of months, I've been experiencing extremely slow
browsing when fiddler was open (fiddler could be 'stuck' on 50% of the
responses for 3-6 seconds each).
I'm using Chrome as my primary browser so it just occured to me to try
a different browser. Tried FF and everything was fine.
I've read a few posts about the "auto detect proxy" setting but that
was not the case as it was never checked on my machine (Win7/x64 BTW).
So, after digging more (as I was very frustrated and didn't want to
stop using Chrome), I finally found the issue.
I've noticed that the fiddler log had multiple lines with the
following:

[Fiddler] Failed to read HTTP request from (chrome:XXXXXX) new client
socket, port XXXXXX.

This made me browse the Chrome internal settings only to find that by
un-checking the "Use DNS pre-fetching to improve page load
performance" in the "Under the hood" options - SOLVED THE ISSUE!
Browsing (with fiddler open) is now back to normal and fast as
expected.

I've read that the "DNS pre-fetching" feature in Chrome has bad
performance and many people are disabling it, but, apparently,
combined with Fiddler, it's a lot worse.

Hope this helps someone.

[EricLaw]

Interesting, thanks for the tip. For what it's worth, I've never seen
this behavior, and DNS Prefetch ought not have anything to do with
this, because DNS Prefetch shouldn't be active when a proxy server is
present.

Having said that, I've never seen their code, and maybe they have some
kind of bug somewhere.

thanks,
-Eric

[Chad Sowald]

@NiceGuyM - this may be worth posting as an issue or something to
investigate on the Chromium Issue list: http://code.google.com/p/chromium/issues/list

You might get some feedback from the developers who would be more
familiar with the DNS pre-fetching feature.