page generation time and actual response time difference
troy.hakala at gmail.com
Thu Dec 31 22:05:18 MSK 2009
firebug is affected by firefox's speed, the client machine's speed and the speed of your network. on a page I just tested on my site, firebug says 10-100ms per request just in "waiting for response" while ab (Apache Bench) says it takes at most 19ms total (not just waiting for response) per request under load (i.e., when doing 4000 requests with a concurrency of 40). curl says it takes 3-10ms total (not just waiting for response). I'm running ab and curl on the same machine with Firefox.
remove components until you find the slow piece. what does ab or curl (using -w and time_pretransfer) say? how fast is it if you run ab or curl on the nginx server itself rather than across the network? what does firebug or curl say about a known fast site like www.google.com? I get about 100ms in Firebug's "waiting for response" against google.com but curl ranges from 3-45ms.
and how big (in bytes) is your home page? does it change significantly for smaller pages?
Firebug is very erratic too, if I hit refresh several times it can increase by a factor of 10. I wouldn't put too much weight on what Firebug says. I don't know anything about Pingdom.
On Dec 31, 2009, at 7:35 AM, Ehud Rosenberg wrote:
> Hi all,
> I'm seeing something a bit odd in our rails app. In the application log
> file I see the homepage is constantly generated in under 350ms,
> sometimes going as far down as 150ms. However, when I run firebug
> locally or Pingdom to test how long it takes to load our site, it
> constantly shows a much larger "waiting for response" time, usually
> around 600-700ms. I was wondering if anyone can help me figure out the
> large difference? Where are those 300-400ms spent?
> Is it possibly related to nginx configuration?
> The server is an 8cpu, 8gb ubuntu installation with a server load of
> about 1.6.
> Posted via http://www.ruby-forum.com/.
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