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IE8 == Worse Performance?
06-27-2010, 05:17 PM (This post was last modified: 06-27-2010 05:18 PM by jarrod1937.)
Post: #11
RE: IE8 == Worse Performance?
(06-27-2010 02:15 AM)pmeenan Wrote:  
(06-26-2010 11:45 PM)jarrod1937 Wrote:  Which script exactly? The only thing i see is the lt ie7 conditonal statement, can those cause image downloading to be blocked? Keep in mind the link in the test goes straight to our old, currently live, site. On the old site there is some inline javascript right after the css, but it has been removed in our new site (the one in that test).

This right at the end of your head:

<script type="text/javascript" language="JavaScript">
function popUp(URL) {
day = new Date();
id = day.getTime();
eval("page" + id + " = window.open(URL, '" + id + "', 'toolbar=0,scrollbars=0,location=0,statusbar=0,menubar=0,resizable=1,width=730,h​eight=618,left = 275,top = 203');");
}</script>

Yes, that is from the old site, to my knowledge that code is not included in the new one. If you view the new site it should look something like this:
[Image: 1_screen_doc.jpg]

The test i ran is scripted so that it uses the ip of our test server. I'll pm you the details to connect to the test server.
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06-27-2010, 11:14 PM
Post: #12
RE: IE8 == Worse Performance?
Looks like ADC is the app accelerator-side of a CDN (http://en.wikipedia.org/wiki/Application..._network). I had to Google for it though (which is probably a good indicator that they need to explain a bit more).

The main alternatives in this space that I'm aware of are:

Aptimize - http://www.aptimize.com/
AcceloWeb - http://acceloweb.com/

There are also a bunch of software solutions that handle bits and pieces (like W3 total cache for wordpress, etc) but Strangeloop is the only one I'm aware of that inlines the images. They're also the only cloud-based solution that I know of (Aptimize and AcceloWeb require access to the apache config itself or a dedicated box).

They had a good walkthrough at velocity last week where they took a site and enabled individual acceleration features to see the impact. The slides are available here: http://www.webperformancetoday.com/2010/...-our-eyes/

Thanks,

-Pat
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06-29-2010, 06:54 PM
Post: #13
RE: IE8 == Worse Performance?
A couple of comments about AcceloWeb:
1. AcceloWeb does image inlining, both using data:uri and MHTML.
2. AcceloWeb runs on the cloud as well and while one of its configurations is on a dedicated physical machine, there are other cloud-based configurations as well.

Leonid Fainberg
CTO & Co-Founder
AcceloWeb



(06-27-2010 11:14 PM)pmeenan Wrote:  Looks like ADC is the app accelerator-side of a CDN (http://en.wikipedia.org/wiki/Application..._network). I had to Google for it though (which is probably a good indicator that they need to explain a bit more).

The main alternatives in this space that I'm aware of are:

Aptimize - http://www.aptimize.com/
AcceloWeb - http://acceloweb.com/

There are also a bunch of software solutions that handle bits and pieces (like W3 total cache for wordpress, etc) but Strangeloop is the only one I'm aware of that inlines the images. They're also the only cloud-based solution that I know of (Aptimize and AcceloWeb require access to the apache config itself or a dedicated box).

They had a good walkthrough at velocity last week where they took a site and enabled individual acceleration features to see the impact. The slides are available here: http://www.webperformancetoday.com/2010/...-our-eyes/

Thanks,

-Pat
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06-29-2010, 08:10 PM
Post: #14
RE: IE8 == Worse Performance?
I would love to see some examples of the MHTML and data:uri concepts.

From my understanding, both of these actually embed images within the main document.

If that is correct, the download time each image is added to the main document.

So basically the difference would be the DNS lookup and / or time to first byte would not exist for the images since they are embedded.

While the main document downloads, it is possible to have the images downloading as well and in parallel.

I am not seeing how the MHTML or data:uri concepts would make the page faster except if the time to first byte or dns lookup time for the images is huge.
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06-29-2010, 10:11 PM
Post: #15
RE: IE8 == Worse Performance?
There is actually another advantage to these techniques and it's bandwidth utilization. During the time a browser downloads multiple images, you have to take into account "dead" times when the connection is taken but nothing is downloaded yet (during the time it takes to connect to the server and the time it takes the server to send the first byte). Also, it takes the browser time to parse the HTML (and it is delayed even longer by blocking objects such as script tags. If you look at the waterflow chart of a typical webpage, you'll see many "holes" when the bandwidth is not utilized well.

Combining the images to one big container, solves this problem because while this container is being downloaded, the bandwidth is utilized well.


Also, you talk about time to first byte as if it is neglectable.
If you take a typical media rich web page, it has about 100 images (remember that all the background images are images too and every round corner is an image). Assuming you don't use a CDN (and even then, depends on how distributed the CDN is), you can get network latency of about 100ms when accessing US based sites from other locations in the US. For international locations, it's even worse. Also, the server needs time to process every request. This is relevant even for static images, as the server has a queue of request and the busier it is, the more time every request spends in the queue. Thus - you can easily add 20-50 ms of additional delay for every resource.

Now, if we do the math: 100 [images] * 100 [ms] + 100 [images] * 50 [ms] = 15 sec.

Now, of course some of it happens in parallel because the browser maintains several simultaneous connections, (and we can also talk about primed cache and less content-rich sites) but you can see that the sum of the penalties that you pay by not combining images is measured in seconds and this is a substantial penalty to pay.

Leonid Fainberg
CTO & Co-Founder
AcceloWeb

(06-29-2010 08:10 PM)green-watch.org Wrote:  I would love to see some examples of the MHTML and data:uri concepts.

From my understanding, both of these actually embed images within the main document.

If that is correct, the download time each image is added to the main document.

So basically the difference would be the DNS lookup and / or time to first byte would not exist for the images since they are embedded.

While the main document downloads, it is possible to have the images downloading as well and in parallel.

I am not seeing how the MHTML or data:uri concepts would make the page faster except if the time to first byte or dns lookup time for the images is huge.
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06-29-2010, 10:38 PM
Post: #16
RE: IE8 == Worse Performance?
Yeah, what Leonid said :-) (and sorry about the mis-statement on the cloud support - great to hear it is available).

The connection and request times are almost always what makes a site slow. If you got to ~slide 113 in Strangeloop's deck you can see the impact for the Velocity web site with combining (though it included css, js and images in one step). The page load times went down from 8.3 seconds to 3.4 seconds. It is the same reason people use sprites but the Data URI's and MHTML support is more flexible and works for other images, not just background ones which makes it really useful for things like product thumbnails.

In the case of MHTML you can reference them in an external file so you can group the images or put them all in a single external file that can be downloaded in parallel with other activity (or, more importantly, cached). Data URI's aren't quite as flexible but they can be inline in the external CSS files.

It's not the first optimization I'd recommend but once you have tackled the rest of the low-hanging-fruit it is one of the optimizations that can still have a large impact on the remaining page load.
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06-29-2010, 10:44 PM
Post: #17
RE: IE8 == Worse Performance?
Also, when considering combining and inlining any resources (images among them), you should also consider the downsides.
The two major downsides are:
1. They are difficult to maintain. Every time you want to change your page (other than small text changes), you might have to generate the combined/inlined resource over again.
2. They might harm the efficiency of browser's cache. Every time you change a single resource in the combined/inlined container, the browser will have to download the entire container all over again, instead of just downloading the changed resource.

Leonid Fainberg
CTO & Co-Founder
AcceloWeb


(06-29-2010 10:38 PM)pmeenan Wrote:  Yeah, what Leonid said :-) (and sorry about the mis-statement on the cloud support - great to hear it is available).

The connection and request times are almost always what makes a site slow. If you got to ~slide 113 in Strangeloop's deck you can see the impact for the Velocity web site with combining (though it included css, js and images in one step). The page load times went down from 8.3 seconds to 3.4 seconds. It is the same reason people use sprites but the Data URI's and MHTML support is more flexible and works for other images, not just background ones which makes it really useful for things like product thumbnails.

In the case of MHTML you can reference them in an external file so you can group the images or put them all in a single external file that can be downloaded in parallel with other activity (or, more importantly, cached). Data URI's aren't quite as flexible but they can be inline in the external CSS files.

It's not the first optimization I'd recommend but once you have tackled the rest of the low-hanging-fruit it is one of the optimizations that can still have a large impact on the remaining page load.
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06-30-2010, 12:44 AM (This post was last modified: 06-30-2010 12:45 AM by jarrod1937.)
Post: #18
RE: IE8 == Worse Performance?
Quick question patrick, did you see anything once you connected to the new site that may be causing IE8 specifically to be behaving slower than IE7? Any input would be appreciated, find it annoying i can't seem to get it running fast for both.
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07-02-2010, 05:17 AM
Post: #19
RE: IE8 == Worse Performance?
As an update, apparently internet speed is not a factor in the spacey-ness of the connections. Here is a test running at 5 megabits (same up and delay as dsl):
http://www.webpagetest.org/result/100701...1/details/
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07-02-2010, 05:35 AM
Post: #20
RE: IE8 == Worse Performance?
Have you tried with different latencies to see if it is timing related? The bandwidth is hardly ever the constraining factor.
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