Process-per-site-instance and Process-per-site should be understood? I read the explanation here, I feel that there is no difference between the two arguments? It is hoped that God can give some simpler explanations. Examples are better?
Process-per-site-instance:
Chromium creates a renderer process for each instance of a site the user visits. This ensures that pages from different sites are rendered independently, and that separate visits to the same site are also isolated from each other. Thus, failures (e.g., renderer crashes) or heavy resource usage in one instance of a site will not affect the rest of the browser. This model is based on both the origin of the content and relationships between tabs that might script each other. As a result, two tabs may display pages that are rendered in the same process, while navigating to a cross-site page in a given tab may switch the tab's rendering process.
Process-per-site:Chromium also supports a process model that isolates different sites from each other, but groups all instances of the same site into the same process. This model is based on the origin of the content and not the relationships between tabs.
link:
One of the most obvious difference is that under Process-per-site mode, it makes sure that each site uses no more than one process, while in Process-per-site-instance (which is the default mode) one sites could have more than one processes.
Here is a simple experiment to show the difference:
Process-per-site-instance
First open the Chromium (I did on Chromium build 778138, I think the result will be the same on any recent Chrome build) in the normal/default mode.
Then open two github.com tabs.
Open the Task Manager (under More Tools in Chromium).
As you can see these two tabs have two different process ID 86892 and 86894
Process-per-site
Quit Chromium and reopen it with addition argument by running this in the Terminal to enter the process per site mode (I'm using MacOS, for Windows you could follow this):
open -a "Chromium" --args --process-per-site
Then open two github.com tabs.
Open the Task Manager same as the previous step.
As you can see the two github tabs have the same process ID 86831
Another interesting observation is that in the first one (Process-per-site-instance) the total Memory footprint is around 125 MB while the second one (Process-per-site) is around 88 MB, which is 30% less! But the downside is, as stated on Chromuim website:
(Process-per-site) Can result in large renderer processes. Sites like google.com host a wide variety of applications that may be open concurrently in the browser, all of which would be rendered in the same process. Thus, resource contention and failures in these applications could affect many tabs, making the browser seem less responsive. It is unfortunately hard to identify site boundaries at a finer granularity than the registered domain name without breaking backwards compatibility.
Further reading:
In this article the author did some interesting experiences under the Process-per-site-instance mode and I think it could further improve your understanding on the Chrome Process Models.
With an increasing mobile user base I would like to be able to gauge a baseline for site performance. Typically I can do this using chrome dev tools, checking when DOMContentLoaded finishes, and checking all my javascript tags to make sure they're in acceptable threshholds. How would I go about automating this so I can create performance dashboards?
Maybe phantomjs, selenium can do this? What headless chrome implementation could I use to achieve this.
You can use Lighthouse to capture a variety of performance metrics.
For real user metrics, you can instrument your app however you see fit with the User Timing API.
im not sure why (probably an update) but chrome has significantly lost performance while running some things I've made with three.js. I haven't worked on anything in a month and now that i've returned to my project i've found things are suddenly running much slower than they used to. I used to get a smooth 60 fps+, and now things are chugging along at 20 fps in one of my programs.
Just to be clear, I've changed absolutely nothing. I simply opened my projects a month later and the performance has dropped by 40+ fps, which is frightening. This is true for anything using three.js.
I'm wondering if anyone knows what the issue is.
EDIT:
http://gamejolt.com/games/arcade/tiny-tank/27522/
This is an application I've made which has significantly degraded in performance, at least on my machine. There also strange shading behavior which has appeared on the shading of certain objects due to hidden lights(?).
I'm using the WebGL renderer by the way.
I'm using Three.js version r66, since there are no migration instructions to move to any higher versions on github.
Go to chrome://flags and make sure Override software rendering list is set to enabled. This will make sure the GPU-acceleration is enabled on unsupported system configurations
Is there a way I can simulate various connection speeds from within Chrome?
I need to be able to check http://localhost with varying speeds.
I know there are standalone applications that can do this, but I'd rather do this inside Chrome.
If you are running Linux, the following command is really useful for this:
trickle -s -d 50 -w 100 firefox
The -s tells the command to run standalone, the -d 50 tells it to limit bandwidth to 50 KB/s, the -w 100 set the peak detection window size to 100 KB. firefox tells the command to start firefox with all of this rate limiting applied to any sites it attempts to load.
Update
Chrome 38 is out now and includes throttling. To find it, bring up the Developer Tools: Ctrl+Shift+I does it on my machine, otherwise Menu->More Tools->Developer Tools will bring you there.
Then Toggle Device Mode by clicking the phone in the upper left of the Developer Tools Panel (see the tooltip below).
Then activate throttling like so.
If you find this a bit clunky, my suggestion above works for both Chrome and Firefox.
I'd recommend Charles Proxy - you can choose to slowdown individual sites, also has a whole bunch of HTTP inspection tools.
Edit:
As of June 2014, Chrome now has the ability to do this natively in DevTools - you'll need Chrome 38 though.
The option is accessible from the Network tab via a drop down at the end of the toolbar.
Starting with Chrome 38 you can do this without any plugins. Just click inspect element (or F12 hotkey), then click on toggle device mod (the phone button)
and you will see something like this:
Among many other features it allows you to simulate specific internet connection (3G, GPRS)
As of today you can throttle your connection natively in Google Chrome Canary 46.0.2489.0. Simply open up Dev Tools and head over to the Network tab:
As Michael said, the Chrome extension API doesn't offer a reliable way of doing this. On the other hand: there's a software I've been using myself for quite some time.
Try Sloppy, a Java application that simulates low bandwidth. It's browser independent, it's very easy to use and, best of all, it's free!
If you are on a Mac, the Chrome dev team recommend the 'Network Link Conditioner Tool'
Either:
Xcode > Open Developer Tool > More Developer Tools > Hardware IO Tools for Xcode
Or if you don't want to install Xcode:
Go to the Apple Download Center and search for Hardware IO Tools
https://developer.apple.com/downloads/index.action
Original article: https://helpdeskgeek.com/networking/simulate-slow-internet-connection-testing/
Simulate Slow Connection using Chrome
Go ahead and install Chrome if you don’t already have it installed on your system. Once you do, open a new tab and then press CTRL + SHIFT + I to open the developer tools window or click on the hamburger icon, then More tools and then Developer tools.
This will bring up the Developer Tools window, which will probably be docked on the right side of the screen. I prefer it docked at the bottom of the screen since you can see more data. To do this, click on the three vertical dots and then click on the middle dock position.
Now go ahead and click on the Network tab. On the right, you should see a label called No Throttling.
If you click on that, you’ll get a dropdown list of a pre-configured speed that you can use to simulate a slow connection.
The choices range from Offline to WiFi and the numbers are shown as Latency, Download, Upload. The slowest is GPRS followed by Regular 2G, then Good 2G, then Regular 3G, Good 3G, Regular 4G, DSL and then WiFi. Pick one of the options and then reload the page you are on or type in another URL in the address bar. Just make sure you are in the same tab where the developer tools are being displayed. The throttling only works for the tab you have it enabled for.
If you want to use your own specific values, you can click the Add button under Custom. Click on the Add Custom Profile button to add a new profile.
When using GPRS, it took www.google.com a whopping 16 seconds to load! Overall, this is a great tool that is built right into Chrome that you can use for testing your website load time on slower connections. If you have any questions, feel free to comment. Enjoy!
In Chrome Canary now you can limit the network throughput. This can be done in the "Network" options of the "Emulation" tab of the Console in the Dev Tools.
You might need to activate the Chrome flag "Enable Developer Tools experiments" (chrome://flags/#enable-devtools-experiments) (chrome://flags) to see this new feature. You can simulate some low bandwidth (GSM, GPRS, EDGE, 3G) for mobile connections.
if you're not familiar with Fiddler - please do. It's a great debugging tool for HTTP. You also have the option to limit the bandwidth.
I don't think what you ask can be done by chrome alone. The closest I could find was this, which isn't what you want. I getting a chrome plugin to do it would be Hard.
A web proxy running on your local machine could achieve the effect you want. A search for "throttling proxy" came up with this, for example.
As suggested on the Chrome Mobile Emulation page, you can use Clumsy on Windows, Network Link Conditioner on Mac OS X and dummynet on Linux.
If you are using OSX, you can use: Network Link Conditioner
Here you can select different profiles ie. 100% Loss, 3G, DSL etc.
Please find the below link to download Network Link Conditioner here
I want to run a analyse for my website , calculate how much traffic it cost for each page , is that possible with Chromium Browser , maybe it's supported , but I didn't find it.
Thanks.
If you want to analyse performance problems for your website, then Speed Tracer would be the best chrome extension. Speed Tracer in Chrome Web Store
Speed Tracer is a tool to help you identify and fix performance problems in your web applications. It visualizes metrics that are taken from low level instrumentation points inside of the browser and analyzes them as your application runs. Speed Tracer is available as a Chrome extension and works on all platforms where extensions are currently supported (Windows and Linux).
Using Speed Tracer you are able to get a better picture of where time is being spent in your application.
You should be able to work it out via the developer tools, but I'm not convinced it's the best way of getting that data.
It's there, but personally I'd recommend something like;
http://piwik.org/
From their blurb:
"Piwik is a downloadable, Free/Libre (GPLv3 licensed) real time web analytics software >program. It provides you with detailed reports on your website visitors: the search >engines and keywords they used, the language they speak, your popular pages… and so much >more."
Which is set up on the server and should give you a much better view of the type of data you're looking for.
Hope that helps.