Thanks for the in-depth feedback.
Interestingly, for that same test page in FF 3.6 and Page Speed 1.6, I
get the same overall score but with slightly different results:
Minimize DNS lookups (red)
The domains of the following urls only serve one resource each. If
possible, avoid the extra DNS lookups by serving these resources from
existing domains.
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/main.js
* http://maps.google.com/maps/api/js?sensor=false
* http://code.google.com/apis/maps/documentation/v3/examples/map-simple.html
Serve resources from a consistent URL (yellow)
The following resources have identical contents, but are served from
different URLs. Serve these resources from a consistent URL to save 2
request(s) and 356B.
* http://mt0.google.com/vt/v=ap.116&hl=en-US&x=236&y=154&z=8&s=Galile
* http://mt3.google.com/vt/v=ap.116&hl=en-US&x=237&y=153&z=8&s=
* http://mt1.google.com/vt/v=ap.116&hl=en-US&x=237&y=154&z=8&s=G
Defer loading of JavaScript (yellow)
76.4% of the JavaScript loaded by this page had not been invoked by
the time the onload handler completed.
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/main.js
323 functions uncalled of 424 total functions. (Toggle Function View)
* http://code.google.com/apis/maps/documentation/v3/examples/map-simple.html
23 functions uncalled of 26 total functions. (Toggle Function View)
Serve static content from a cookieless domain (yellow)
Serve the following static resources from a domain that doesn't set
cookies:
* http://mt0.google.com/vt/v=ap.116&hl=en-US&x=234&y=153&z=8&s=Galileo
* http://mt2.google.com/vt/v=ap.116&hl=en-US&x=234&y=154&z=8&s=
* http://mt1.google.com/vt/v=ap.116&hl=en-US&x=235&y=153&z=8&s=Ga
* http://mt3.google.com/vt/v=ap.116&hl=en-US&x=235&y=154&z=8&s=Gal
* http://mt3.google.com/vt/v=ap.116&hl=en-US&x=233&y=153&z=8&s=Gali
* http://mt1.google.com/vt/v=ap.116&hl=en-US&x=233&y=154&z=8&s=Galil
* http://mt2.google.com/vt/v=ap.116&hl=en-US&x=236&y=153&z=8&s=Galil
* http://mt0.google.com/vt/v=ap.116&hl=en-US&x=236&y=154&z=8&s=Galile
* http://mt2.google.com/vt/v=ap.116&hl=en-US&x=232&y=153&z=8&s=G
* http://mt0.google.com/vt/v=ap.116&hl=en-US&x=232&y=154&z=8&s=Ga
* http://mt3.google.com/vt/v=ap.116&hl=en-US&x=237&y=153&z=8&s=
* http://mt1.google.com/vt/v=ap.116&hl=en-US&x=237&y=154&z=8&s=G
2.7kB of cookies were sent with the requests for these resources.
Another difference I notice between this test page and my page (which
also has Maps loading on page load, along with multiple markers), is
the "Combine external Javascript" rule is the only red one:
There are 9 JavaScript files served from maps.gstatic.com. They should
be combined into as few files as possible.
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/main.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/common.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/mapview.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/util.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/marker.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/controls.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/streetview.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/infowindow.js
* http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/stats.js
In the
http://code.google.com/apis/maps/documentation/v3/examples/map-simple.html
test page, I can see those files getting loaded, but yet they aren't
being reported. Do you know why this would be?
Thanks again!
On Feb 1, 12:39 am, Ben Appleton <apple...@google.com> wrote:
> I've spent some time looking further into the Google Page Speed score for
> Maps API v3. I'm using the v3 "hello world" example for
> reference:http://code.google.com/apis/maps/documentation/v3/examples/map-simple...
> Attached is a screenshot of Page Speed with each column collapsed. I'm
> loading the above page in FireFox 3.6, waiting for everything to download,
> then turning on page speed. I will address each Page Speed rule in turn
> below.
>
> ------------------
> *Serve resources from a consistent URL (red)*
> The following resources have identical contents, but are served from
> different URLs. Serve these resources from a consistent URL to save 12
> request(s) and 2.1KiB.
>
> -http://mt0.google.com/vt/v=ap.116&hl=en-US&x=236&y=154&z=8&s=Galile*-
> map tile*
> -http://mt2.google.com/vt/v=ap.116&hl=en-US&x=236&y=155&z=8&s=Galileo*-
> map tile*
> - ...
>
> These tiles consist entirely of ocean. Page Speed will only report this
> rule if your viewport contains tiles of constant color, such as these blue
> ocean tiles. Each ocean tile is 230 bytes.
>
> This is a chicken-and-egg problem: for the browser to download these tiles
> from the same URL it must know these are ocean tiles. If the browser knew
> these were ocean tiles it would not need to download them, since it could
> use a blue div. So, I consider this a false positive from Page Speed.
>
> ------------------
> *Minimize DNS lookups (yellow)*
> The domains of the following urls only serve one resource each. If possible,
> avoid the extra DNS lookups by serving these resources from existing
> domains.
>
> -http://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/main.js- *JS*
> -http://maps.google.com/maps/api/js?sensor=false- *API bootstrap*
> -
> http://code.google.com/apis/maps/documentation/v3/examples/map-simple...-
> *Test page*
>
> ------------------
> The first item is the API JS, loaded from maps.gstatic.com. But
> maps.gstatic.com is also used to load the JS modules: common.js, mapview.js,
> util.js, controls.js, and stats.js. Likewise, the second item is the Maps
> API v3 bootstrap, fetched from maps.google.com. But maps.google.com is also
> used for service requests, such as the copyright and authentication
> services. I suspect Page Speed flags the main JS module and the bootstrap
> because they are requested before page load, whereas the remaining modules
> and service requests come after the page load. But that is intentional:
> Maps API v3 loads as little as possible upfront to minimize the time to show
> a map.
>
> We could save 1 DNS lookup by merging maps.google.com and maps.gstatic.com.
> However maps.google.com serves cookies whereas maps.gstatic.com does not.
> So merging these domains would bloat the HTTP request headers for our
> static files. This is not worth saving 1 DNS lookup.
>
> The third item is the test page. Usually the API is loaded on to a
> developer's site, and the developer would load other resources from their
> site, so Page Speed would not flag the containing page.
>
> ------------------
> *Serve static content from a cookieless domain (yellow)*
> Serve the following static resources from a domain that doesn't set cookies:
>
> -http://mt1.google.com/vt/v=ap.116&hl=en-US&x=235&y=153&z=8&s=Ga*- map
> tile*
> -http://mt3.google.com/vt/v=ap.116&hl=en-US&x=235&y=154&z=8&s=Gal*- map
> tile*
> - ...
>
> ------------------
> This is a good suggestion: our tile servers could be on domain other than
> google.com. I'll follow this up.
>
> ------------------
> *Leverage browser caching (green)*
> The following resources specify a "Vary" header that disables caching in
> most versions of Internet Explorer. Fix or remove the "Vary" header for the
> following resources:
>
> -http://maps.google.com/maps/api/js?sensor=false- *API bootstrap*
>
> The following cacheable resources have a short freshness lifetime. Specify
> an expiration at least one month in the future for the following resources:
>
> -http://maps.google.com/maps/api/js?sensor=false- *API bootstrap*
>
> *Non-scoring information*
> To further improve cache hit rate, specify an expiration one year in the
> future for the following cacheable resources:
>
> -http://mt0.google.com/vt/v=ap.116&hl=en-US&x=232&y=152&z=8&s=*- map
> tile*
> -http://mt0.google.com/vt/v=ap.116&hl=en-US&x=232&y=154&z=8&s=Ga*- map
> tile*
> - ...
>
> The following resources are explicitly non-cacheable. Consider making them
> cacheable if possible:
>
> -
>
> http://gg.google.com/csi?v=2&s=mapsapi3&action=apiboot&rt=jl.582,mjs....,...<http://gg.google.com/csi?v=2&s=mapsapi3&action=apiboot&rt=jl.582,mjs....>
> * - latency logging*
> -
>
> http://maps.google.com/maps/api/js/AuthenticationService.Authenticate......<http://maps.google.com/maps/api/js/AuthenticationService.Authenticate...>
> * - authentication*
> -
>
> http://maps.google.com/maps/api/js/CopyrightService.GetCopyrightStrin......<http://maps.google.com/maps/api/js/CopyrightService.GetCopyrightStrin...>
> * - copyrights*
>
> ------------------
> The API bootstrap includes 2 HTTP response headers of interest here:
> "Cache-Control: public, max-age=600" and "Vary: Accept-Language". Public
> caching allows intermediate proxies and internet service providers (ISPs) to
> cache the API bootstrap, which reduces the round trip time (RTT) for your
> browser to load the bootstrap from a cold cache. "Vary: Accept-Language"
> prevents responses for 1 language being served to users who prefer other
> languages.
>
> Unfortunately a popular browser does not cache resources with the "Vary:
> Accept-Language" header, which is why Page Speed flags this as a potential
> issue. That browser will request the API bootstrap anew each time, though
> the request may be satisfied by their ISP or a caching proxy which would
> reduce their RTT. Users of other browsers will see a net win in latency, as
> the first load may be satisfied by a proxy while subsequent loads will be
> satisfied by their browser's cache. This was a design choice to minimize
> average latency across all users, and we'll be keeping an eye on browser
> behavior to see if this is a good tradeoff.
>
> Page Speed also flags the API bootstrap as having a short freshness lifetime
> (10 minutes, versus the recommended 1 month). The API bootstrap contains
> configuration data which changes over time, such as the latest API version,
> tile versions, and so on. If the API bootstrap were cached for a month we
> could only release new tile sets and JS versions each month, so that is not
> an option. Even though 10 minutes is short, the API bootstrap is downloaded
> tens of thousands of times every 10 minutes, so caching proxies may still
> serve the bulk of API bootstrap requests.
>
> Page Speed suggests setting the expiration date for our map tiles 1 year in
> the future. They are currently served with "Cache-Control: public,
> max-age=22222222", or 8.5 months. The difference is not significant.
>
> The last 3 resources are listed as non-cacheable:
>
> 1. Latency logging: while the API loads we measure time to load the API
> javascript, map tiles, and so on. Well after the page has finished loading
> we log these statistics back to the server. We analyze these logs to
> measure the effect of latency optimizations and to plan future
> improvements.
> 2. Authentication: the authentication request replaces the API key system
> from Maps API v2. The key system was cumbersome as it tied a site to 1
> domain, keys were long which bloated request URLs, and keys added entropy
> to
> request URLs which made caching ineffective. The authentication service is
> intentionally not cacheable so that we can quickly shut down a site that
> contravenes our terms.
> 3. Copyrights: the copyrights service tells the API which data provider
> attributions to display for the current map viewport. The request contains
> the exact map viewport; so much entropy makes caching ineffective. It's
> possible to quantize the user's viewport to reduce request entropy, but
> making the copyright appear a few milliseconds faster does not seem like a
> big win for users.
>
> ------------------
> *Leverage proxy caching (green)*
> Due to a bug in some proxy caching servers, the following publicly
> cacheable, compressible resources should use "Cache-Control: private" or
> "Vary: Accept-Encoding":
>
> -http://maps.google.com/maps/api/js?sensor=false- *API bootstrap*
>
> Resources with a "?" in the URL are not cached by most proxy caching
> servers. Remove the query string and encode the parameters into the URL for
> the following resources:
>
> -http://maps.google.com/maps/api/js?sensor=false- *API bootstrap*
>
> ------------------
> As discussed above, we believe that serving the API bootstrap as
> "Cache-Control: public" improves the average latency across all users, but
> we'll be keeping an eye on latency statistics to see if this is a good
> tradeoff.
>
> We know that resources with "?" are not cached by many caching proxies;
> indeed this is why our tile URLs do not contain "?". We could allow sites
> to instead writehttp://maps.google.com/maps/api/js/sensor=false, but that's
> unusual and may confuse some developers. So this is a tradeoff between ugly
> URLs vs improving caching for some proxies.
>
> ------------------
> *Minify HTML** (green)*
> Minifying the following HTML resources could reduce their size by 152B (19%
> reduction).
>
> - Minifying
> http://code.google.com/apis/maps/documentation/v3/examples/map-simple...
> save 152B (19% reduction).
>
> ------------------
> This is our test page, which is designed to be readable. Individual sites
> can optimize their pages for speed to prevent Page Speed from flagging this
> issue.
>
> ------------------
> *Minify JavaScript** (green)*
> There is 130.1kB worth of JavaScript. Minifying could save 117 bytes (0.1%
> reduction).
>
> - Minifyinghttp://maps.google.com/maps/api/js?sensor=falseusing JSMin
> could save 88 bytes (2.3% reduction). See minified
> version<file:///C:/DOCUME~1/appleton/LOCALS~1/Temp/page-speed-javascript/js
> _853699f56e6032f4176da00653515409.js>
> .
> -
> Minifyinghttp://maps.gstatic.com/intl/en_us/mapfiles/api-3/27a/main.jsusing
> JSMin could save 29 bytes (0.1% reduction). See minified
>
> version<file:///C:/DOCUME~1/appleton/LOCALS~1/Temp/page-speed-javascript/ma
> in_122f6ff49a05acb665a49d75f0ac967e.js>
> .
>
> ------------------
> The Maps API v3 JS is already minified by Google's Closure Compiler.
>
> ------------------
> *Optimize images** (green)*
> Optimizing the following image resources could reduce their size by 1.4KiB
> (25% reduction).
>
> - Optimizing
> http://maps.gstatic.com/intl/en_us/mapfiles/mapcontrols3d5.pngcould save
> 288B (10% reduction).* - control sprite*
> - Optimizing
> http://mt3.google.com/vt/v=ap.116&hl=en-US&x=235&y=156&z=8&s=Galilcould
> save 77B (35% reduction).* - map tile*
> - ... more tiles ...
>
> ------------------
> We'll look into these savings.
> ------------------
>
> To sum up: Maps API v3 should load tiles from a cookieless domain, we'll
> take another look at the effect of our HTTP response headers, and we'll
> check the compression of our PNGs.
>
> - BenOn Fri, Jan 29, 2010 at 12:32 PM, Austin <austinhu...@gmail.com> wrote:
> > I tried to reply to an older post directly, but for some reason it's
> > not letting me (http://groups.google.com/group/google-maps-js-api-v3/
> > browse_thread/thread/f4a1f4d703267d48/9e8fcf770d1aed2b?lnk=gst&q=Page<http://groups.google.com/group/google-maps-js-api-v3/browse_thread/th...>
> > +Speed+score#). So here's my reply to that thread:
>
> > I'm having similar issues as Ed. Is there any update on this? Is
> > there a way to only load v3 on a page after the dom has loaded if a
> > user executes a specific action, such as clicking on a "Show Map"
> > button? I've tried multiple different methods to post-load the js
> > (http://maps.google.com/maps/api/js?sensor=false) so it only loads on
> > a certain user action in hopes of not getting my Page Speed score
> > docked from all the Google Maps files, but each time the
> > document.write in it overwrites the main page content.
>
> > --
> > You received this message because you are subscribed to the Google Groups
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> > google-maps-js-api...@googlegroups.com.
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> > google-maps-js-api-v3+unsubscr...@googlegroups.com<google-maps-js-api-v3%2B
> > unsubscr...@googlegroups.com>
> > .
> > For more options, visit this group at
> >http://groups.google.com/group/google-maps-js-api-v3?hl=en.
>
>
>
> page_speed_v3.PNG
> 66KViewDownload
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