Thanks Sebastian. Just a minor clarification - the issue is with both Connect time and DNS.
It sounds like I might have to go back to a Firefox release that is about 2 years old in order to get a working version. That worries me! Is there another group I should post a message on to see if there is any hope of getting this fixed? I wonder if the W3C Navigation Timings are bogus too. I realize that tracking performance when the platform includes things such as DNS prefetch and anticipatory connections can become very complex. I am hoping that the Firefox team considers providing accurate performance information as a priority. - Les On Monday, November 10, 2014 8:30:47 PM UTC-7, [email protected] wrote: > > I am trying to verify that the timings in the Network panel are accurate. > This is for an application performance analysis utility I am developing > for a client. > > I am using a network emulator to force additional artificial latency into > the network. > > My test preconditions are to clear the windows DNS (ifconfig /flushdns), > and set Firefox not to cache any DNS entries (network.dnsCacheExpiration > and network.dnsCacheEntries both set to 0). > > I am trying to validate what I see in the net panel is correct by using > Wireshark to see the actual network traffic. The results prove that the > DNS lookup and connect are being lumped into blocking time. > > I am using a static image from my own website to test. I am adding about > 225ms of RTT latency. > > > http://www.eperformancegroup.com/blog/wp-content/plugins/slideshow-gallery/views/default/images/left.gif?test=xxx > > The FB network panel shows blocking of 843ms, waiting of 283ms > > Wireshark shows DNS lookup time of 567ms > Wireshark shows TCP connect of 275ms. Add in DNS time and the total is > 842ms. > Wireshark shows response time of 284ms > > So - the total times match up - but the network panel lumped both the DNS > time and the TCP connect time into blocking. > > Can this be easily fixed / is there a workaround I might use? HAR file > is attached. > > FF 33.1, Firebug 2.0.6 > > In a repeat test, I can confirm that this is repeatable. > > FB net panel shows blocking of 620ms, wait of 284ms > > "timings": { > "blocked": 620, > "dns": 0, > "connect": 0, > "send": 0, > "wait": 284, > "receive": 0 > }, > > For the repeat test: > > Wireshark shows DNS of 341 ms > Wireshark TCP connect time of 274 ms - a total of 615ms > wireshark shows response time of 283 ms > > > <https://lh5.googleusercontent.com/-d9v5R_kJSK4/VGGA2Xhq64I/AAAAAAAAAAM/ROyp-c_ZgGM/s1600/FB%2Bnetwork%2Bpanel.png> > > > > > > > > > <https://lh5.googleusercontent.com/-1_ADrfv5OKQ/VGGA5xNczhI/AAAAAAAAAAU/Hj1V73S8Ubc/s1600/DNS%2Blookup%2B576ms.png> > > > > <https://lh6.googleusercontent.com/-WK_RIPk6KhI/VGGA_-O9z-I/AAAAAAAAAAc/CXMTVp26GHk/s1600/TCP%2Bconnect%2B275ms.png> > > > > <https://lh6.googleusercontent.com/-yJE4gR-dDAs/VGGBC2a5T1I/AAAAAAAAAAk/m3k_bcboS7E/s1600/response%2B284ms.png> > > > > > -- You received this message because you are subscribed to the Google Groups "Firebug" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/firebug. To view this discussion on the web visit https://groups.google.com/d/msgid/firebug/98a275be-bf0a-471d-a644-a84a6299615a%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
