chrome-har: Transfer sizes seem incorrect

Original issue (https://github.com/sitespeedio/sitespeed.io/issues/1467)

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Hello there,

I’ve been trying to run sitespeed on a page behind login (I believe that’s all good now) but I am seeing different results (on requests numbers for example) between doing it “manually” in my Chrome browser (and looking in the Network tab) and when doing it via the sitespeed command.

I’ve setup a test page with a login / password for you to have a look here: http://lumsites-sandbox.appspot.com/a/lumapps/home/sitespeed-homepage-test-private (see credentials in the preScript login script I use).

Here’s the command I use:

docker-compose run sitespeed.io --preScript sitespeed-login.js http://lumsites-sandbox.appspot.com/a/lumapps/home/sitespeed-homepage-test-private -n 3 -b chrome --browsertime.chrome.args no-sandbox --browsertime.chrome.args disk-cache-dir=/dev/null --browsertime.chrome.args disk-cache-size=1 --browsertime.chrome.args media-cache-size=1 --browsertime.pageCompleteCheck 'return (function() {try { return (Date.now() - window.performance.timing.loadEventEnd) > 15000;} catch(e) {} return true;})()' --graphite.host=graphite --summary-detail

These are the versions it uses on my machine:

Versions OS: linux 4.9.8-moby nodejs: v6.9.1 sitespeed.io: 4.4.2 browsertime: 1.0.0-beta.25 coach: 0.31.0

Which gives me the following results:

Total requests 31 Image requests 3 CSS requests 4 Javascript requests 7 Font requests 0

When I do the same process manually (logging in, then going to the test page and looking up the numbers in Chrome > Network with cache disabled) I get this:

Total requests 51 Image requests 4 CSS requests 4 Javascript requests 21 Font requests 5

I suspect it has something to do with the ‘warm cache’ due to the login page visited during the preScript step, but if that’s the case I can’t see how to clear that cache completely before running the tests on my target page.

Thanks in advance for your help or any hint on what I may have done wrong.

For info, I get different results depending on the version of the image of sitespeed I specify in my docker-compose file. The ‘Transfer size’ values look especially different.

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sitespeed 4.0.3

Score / Metric Median ✗ Overall score 67 ✗ Performance score 65 ✗ Accessibility score 65 ✗ Best Practice score 76 √ Fast Render advice 95 ! Avoid scaling images advice 90 √ Compress assets advice 100 ! Optimal CSS size advice 90 ✗ Total size (transfer) 1.9 MB √ Image size (transfer) 642.6 KB ✗ Javascript size (transfer) 1.1 MB ✗ CSS size (transfer) 97.0 KB Total requests 43 Image requests 13 CSS requests 1 Javascript requests 11 Font requests 0 200 responses 43 Domains per page 7 Cache time 10 minutes Time since last modification -1 second RUM Speed Index 5121 First Paint 4840 ms Backend Time 1530 ms Frontend Time 7155 ms

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sitespeed 4.5.1

Score / Metric Median

✗ Overall score 69 ✗ Performance score 68 ✗ Accessibility score 65 ✗ Best Practice score 76 √ Fast Render advice 95 ! Avoid scaling images advice 90 ✗ Compress assets advice 80 ! Optimal CSS size advice 90 √ Total size (transfer) 987.1 KB √ Image size (transfer) 664.9 KB ✗ Javascript size (transfer) 126.5 KB ✗ CSS size (transfer) 113.3 KB Total requests 46 Image requests 17 CSS requests 4 Javascript requests 7 Font requests 0 200 responses 46 Domains per page 8 Cache time 45 minutes Time since last modification -1 second RUM Speed Index 4440 First Paint 2015 ms Backend Time 1389 ms Frontend Time 6617 ms