I am using Google Chrome 63.
In DevTools in Performance tab there are three CPU throttling settings: "No throttling", "4x slowdown" and "6x slowdown".
Is it possible to set custom throttling, for example "20x slowdown"? It could be via setting some flag in chrome.exe file or programmatically via NodeJS library.
I found that Lighthouse library has kind of helpful function but if I change the default value inside it (CPU_THROTTLE_METRICS seems to be equal to 4) from 4 to (for example) 20 and run it, how can I be sure it really is 20x slowed down?
Also, I would like to know, if it is possible to do such simulated "slow down" to the GPU in similar way?
Thanks for any advice.
Custom values for Emulation.setCPUThrottlingRate can be set right in Chrome, but you need to open a Dev Tools window on the Dev Tools window to change the setting programatically.
Open Dev Tools; make sure it is detached (open in its own window).
Open Dev Tools again on the Dev Tools window from step 1 using the key combination Cmd-Opt-i (Mac) or Ctrl-Shift-i (Windows).
Run the following in the Console tab: await Main.MainImpl.sendOverProtocol('Emulation.setCPUThrottlingRate', {rate: 40});
This example will throttle Chrome performance by 40x. NOTE: Passing 1 for rate turns off throttling.
The first Dev Tools window created in Step 1 may be re-docked after creating the second Dev Tools window.
Lighthouse uses Emulation.setCPUThrottlingRate command in the Chrome DevTools Protocol:
https://chromedevtools.github.io/devtools-protocol/tot/Emulation#method-setCPUThrottlingRate
You can monitor the protocol this way:
https://umaar.com/dev-tips/166-protocol-monitor/
You'll see this command in the protocol log when you switch with the throttling setting in the performance panel.
If you're asking how to be sure if it works - here is the implementation from Chromium source code:
https://github.com/chromium/chromium/blob/master/third_party/blink/renderer/platform/scheduler/util/thread_cpu_throttler.h#L21
// This class is used to slow down the main thread for
// inspector "cpu throttling". It does it by spawning an
// additional thread which frequently interrupts main thread
// and sleeps.
Hope this helps.
On Linux you can use cpulimit
sudo apt-get install cpulimit
# -l 5 means 5% , or 20x slowdown
cpulimit -l 5 chromium-browser
Related
One of my VIP customers said that he could not open my website.
So I checked on his chrome dev tool remotely. And found out some static resources kept pending until they failed to load. (as shown below)
After I turn on that Disable cache option and cmd + R refresh that page. It remains the same issue.
The weird thing is until I force close all chrome tabs and reopen this page It just started to work.
I'm pretty sure that my CDN network's healthy and covered his region (he's in China, so I used Aliyun which is almost the biggest CDN provider in China)
Also, I opened his terminal and executed:
ping cdn.shulex-voc.com
which shows there was no package loss.
And
curl -I https://cdn.shulex-voc.com/shulex-voc/5618_1936cc20.js
which shows he can actually load this resource at that moment on the same computer.
I try to start an android sdk emulator, but when I press the back button this error appears:
INFO | Critical: Failed to load https://maps.googleapis.com/maps/api/mapsjs/gen_204?csp_test=true: The 'Access-Control-Allow-Origin' header has a value 'qrc://' that is not equal to the supplied origin. Origin 'qrc://' is therefore not allowed access. (qrc:/html/js/common.js:0, (null))
INFO | Critical: Failed to load https://maps.googleapis.com/maps/api/mapsjs/gen_204?csp_test=true: The 'Access-Control-Allow-Origin' header has a value 'qrc://' that is not equal to the supplied origin. Origin 'qrc://' is therefore not allowed access. (qrc:/html/js/common.js:0, (null))
I use Ubuntu and try to start the emulator through terminal, I use the avdmanager of the google cmdline-tools (latest version) and this is the AVD that I try to use:
Name: my_avd_29ii
Path: /home/user/.android/avd/my_avd_29ii.avd
Target: Google APIs (Google Inc.)
Based on: Android 10.0 (Q) Tag/ABI: google_apis/x86
Sdcard: 512 MB
The best option would (Needs to be done for every emulator you install)
Windows
%USERPROFILE%\.adnroid\avd\<Emulator Name>.avd
Edit config.ini
Change hw.keyboard=no to hw.keyboard=yes
Mac
~/.adnroid/avd/<Emulator Name>.avd
Edit config.ini
Change hw.keyboard=no to hw.keyboard=yes
The answer is based on this article
After looking around I found that there were two ways to push hardware events to the emulator:
First method
This method uses telnet, like so:
telnet 127.0.0.1 5554
auth <auth-key>
event send EV_KEY:KEY_BACK:0
event send EV_KEY:KEY_BACK:1
This is going to simulate the pressing down (0) the releasing (1) of a button.
Second method
This method uses adb, like so:
adb shell input keyevent KEYCODE_BACK
Ok so what?
After trying both, I realized that telnet didn't work but adb did work. I also checked the source code of emulator and saw that telnet relies on the same set of functions that are used by the tool-window. So it's probably a bug, and we can wait for the update to fix it, or...
In the meantime
I downloaded the source code, wrote a janky workaround, and built it. Basically instead of using the keypress method, I use the adb method. If you want here it is. It's quite voluminous so be patient. I included a small script to automatically replace the emulator, just run:
$ chmod +x replace
# ./reaplace path-to-android-sdk
This adds a new flag -use-adb-toolwindow to emulator. When you activate it it will use adb (successfully) for most of keyboard inputs, and home, back, apps and power buttons. Like I said it's a quick fix, but for me it works fine.
Note:
I have no clue where the bug is, so I didn't do any report, hopefuly as more people get this issue it will become clearer.
I'm having a problem with the tablet of Pepper. I am trying to display the index.html to the tablet using the show app box. I made only at the Application one show app box to the root diagram.
An error occurs when I run the application:
[ERROR] behavior.box: _getTabletService: 24 _Behavior__lastUploadedChoregrapheBehavior544669552: / init_8 / Show App_2:
Can not find service 'ALTabletService' in index
In addition, I also get the following awarning:
[WARN] behavior.box: onInput_onStart: 45 _Behavior__lastUploadedChoregrapheBehavior544669552: / init_8 / Show App_2:
Could not find tablet service, so can not set application: .lastUploadedChoregrapheBehavior
Development environment is as follows.
Model name: MacBook Pro
OS: El Capitan 10.11.5
Processor name: Intel Core i5 2.6 GHz
Memory: 16 GB
Graphics: Intel Iris 1536MB
Choreographe: 2.4.3.28
Pepper: 2.4.3.28
Answer please.
Make sure you are connected to the real Pepper and not to the virtual robot (as the virtual robot does not include the ALTabletService).
From experience (Nao) the error would suggest that the module is not available. I don't have the luxury to get my hands on a Pepper yet, but if your are not using a virtual robot, I would fire up a python session and try:
from naoqi import ALTabletService
and see if that goes through. If not, it would mean that there is problem with your SDK installation or env. path. If it goes through, it would be robot issue. Again you NEED TO make sure you are "connected" to a real Pepper, not a virtual robot in Choregraphe, in order for "Show App" to work.
As already pointed out ALTabletService is only available on a real robot (as it runs inside the tablet).
Also sadly this service is not the most stable service on the robot, and it might from time to time be missing (it will restart automatically). So you might need to protect your application against this (by waiting for it, ignoring errors, exiting, ... depending on your workflow).
I am looking for assistance with the proper GDB / OpenOCD initializion and running commands (external tools) to use within Eclipse for flash and RAM debugging, as well as the proper modifications or additions that need to be incorporated in a makefile for flash vs RAM building for this MCU, if this matters of course.
MCU: STM32F103VET6
I am using Eclipse Helios with Zylin Embedded CDT, Yagarto Tools and Bins, OpenOCD 0.4, and have an Olimex ARM-USB-OCD JTAG adapter.
I have already configured the ARM-USB-OCD and added it as an external tool in Eclipse. For initializing OpenOCD I used the following command in Eclipse. The board config file references the stm32 MCU:
openocd -f interface/olimex-arm-usb-ocd-h.cfg -f board/stm32f10x_128k_eval.cfg
When I run this within Eclipse everything appears to be working (GDB Interface, OpenOCD finds the MCU, etc). I can also telnet into OpenOCD and run commands.
So, I am stuck on the next part; initialization and commands for flash and RAM debugging, as well as erasing flash.
I read through several tutorials, and scoured the net, but have not been able to find anything particular to this processor. I am new to this, so I might not be recognizing an equivalent product for an example.
I'm working with the same tool chain to program and debug a STM32F107 board. Following are my observations to get an STM32Fxxx chip programmed and debugged under this toolchain.
Initial Starting Point
So at this point you've got a working OpenOCD to ARM-USB-OCD connection and so you should be all set on that end. Now the work is on getting Eclipse/Zylin/Yagarto GDB combination to properly talk to the STM32Fxxx through the OpenOCD/Olimex connection. One thing to keep in mind is that all the OpenOCD commands to issue are the run mode commands. The configuration scripts and command-line options to invoke the OpenOCD server are configuration mode commands. Once you issue the init command then the server enters run mode which opens up the set of commands you'll need next. You've probably done it somewhere else but I tack on a '-c "init"' option when I call the OpenOCD server like so:
openocd -f /path to scripts/olimex-arm-usb-ocd-h.cfg -f /path to targets/stm32f107.cfg -c "init"
The following commands I issue next are done by the Eclipse Debug Configurations dialogue. Under the Zylin Embedded debug (Native) section, I create a new configuration, give it a name, Project (optional), and absolute path to the binary that I want to program. Under the Debugger tab I set the debugger to Embedded GDB, point to the Yagarto GDB binary path, don't set a GDB command file, set GDB command set to Standard, and the protocol to mi.
The Commands Tab - Connect GDB to OpenOCD
So the next tab is the Commands tab and that's where the meat of the issue lies. You have two spaces Initialize and Run. Not sure exactly what the difference is except to guess that they occur pre- and post-invocation of GDB. Either way I haven't noticed a difference in how my commands are run.
But anyway, following the examples I found on the net, I filled the Initialize box with the following commands:
set remote hardware-breakpoint limit 6
set remote hardware-watchoint-limit 4
target remote localhost:3333
monitor halt
monitor poll
First two lines tell GDB how many breakpoints and watchpoints you have. Open OCD Manual Section 20.3 says GDB can't query for that information so I tell it myself. Next line commands GDB to connect to the remote target at the localhost over port 3333. The last line is a monitor command which tells GDB to pass the command on to the target without taking any action itself. In this case the target is OpenOCD and I'm giving it the command halt. After that I tell OpenOCD to switch to asynchronous mode of operation. As some of the following operations take a while, it's useful not to have OpenOCD block and wait for every operation.
Sidenote #1: If you're ever in doubt about the state of GDB or OpenOCD then you can use the Eclipse debug console to send commands to GDB or OpenOCD (via GDB monitor commands) after invoking this debug configuration.
The Commands Tab - Setting up the User Flash
Next are commands I give in the Run commands section:
monitor flash probe 0
monitor flash protect 0 0 127 off
monitor reset halt
monitor stm32x mass_erase 0
monitor flash write_image STM3210CTest/test_rom.elf
monitor flash protect 0 0 127 on
disconnect
target remote localhost:3333
monitor soft_reset_halt
to be explained in the following sections...
Setting up Access to User Flash Memory
First I issue an OpenOCD query to see if it can find the flash module and report the proper address. If it responds that it found the flash at address 0x08000000 then we're good. The 0 at the end specifies to get information about flash bank 0.
Sidenote #2: The STM32Fxxx part-specific data sheets have a memory map in section 4. Very useful to keep on hand as you work with the chip. Also as everything is accessed as a memory address, you'll come to know this layout like the back of your hand after a little programming time!
So after confirming that the flash has been properly configured we invoke the command to turn off write protection to the flash bank. PM0075 describes everything you need to know about programming the flash memory. What you need to know for this command is the flash bank, starting sector, ending sector, and whether to enable or disable write protection. The flash bank is defined in the configuration files you passed to OpenOCD and was confirmed by the previous command. Since I want to disable protection for the entire flash space I specify sectors 0 to 127. PM0075 explains how I got that number as it refers to how the flash memory is organized into 2KB pages for my (and your) device. My device has 256KB of flash so that means I have 128 pages. Your device has 512KB of flash so you'll have 256 pages. To confirm that your device's write-protection has been disabled properly, you can check the FLASH_WRPR register at address 0x40022020 using the OpenOCD command:
monitor mdw 0x40022020
The resulting word that it prints will be 0xffffffff which means all pages have their write protection disabled. 0x00000000 means all pages have write protection enabled.
Sidenote #3: On the subject of the memory commands, I bricked my chip twice as I was messing with the option bytes at the block starting at address 0x1ffff800. First time I set the read protection on the flash (kind of hard to figure out what your doing if you do that), second time I set the hardware watchdog which prevented me from doing anything afterwards since the watchdog kept firing off! Fixed it by using the OpenOCD memory access commands. Moral of the story is: With great power comes great responsibility.... Or another take is that if I shoot myself in the foot I can still fix things via JTAG.
Sidenote #4: One thing that'll happen if you try to write to protected flash memory is the FLASH_SR:WRPRTERR bit will be set. OpenOCD will report a more user-friendly error message.
Erasing the Flash
So after disabling the write protection, we need to erase the memory that you want to program. I do a mass erase which erases everything, you also have the option to erase by sector or address (I think). Either way you need to erase first before programming as the hardware checks for erasure first before allowing a write to occur. If the FLASH_SR:PGERR bit (0x4002200c) ever gets set during programming then you know you haven't erased that chunk of memory yet.
Sidenote #5: Erasing a bit in flash memory means setting it to 1.
Programming Your Binary
The next two lines after erasure writes the binary image to the flash and reenables the write protection. There isn't much more to say that isn't covered by PM0075. Basically any error that occurs when you issue flash write_image is probably related to the flash protection not being disabled. It's probably NOT OpenOCD though if you're curious you can take enable the debug output and follow what it does.
GDB Debugging
So finally after programming I disconnect GDB from the remote connection and then reconnect it to the target, do a soft-reset, and my GDB is now ready to debug. This last part I just figured out last night as I was trying to figure out why, after programming, GDB wouldn't properly stop at main() after reset. It kept going off into the weeds and blowing up.
My current thinking and from what I read in the OpenOCD and GDB manuals is that the remote connection is, first and foremost, meant to be used between GDB and a target that has already been configured and running. Well I'm using GDB to configure before I run so I think the symbol table or some other important info gets messed up during the programming. The OpenOCD manual says that the server automatically reports the memory and symbols when GDB connects but all that info probably becomes invalid when the chip gets programmed. Disconnecting and reconnecting I think refreshes the info GDB needs to debug properly. So that has led me to create another Debug Configuration, this one just connects and resets the target since I don't necessarily need to program the chip every time I want to use GDB.
Whew! Done! Kind of long but this took me 3 weekends to figure out so isn't too terribly bad I think...
Final sidenote: During my time debugging I found that OpenOCD debug output to be invaluable to me understanding what OpenOCD was doing under the covers. To program a STM32x chip you need to unlock the flash registers, flip the right bits, and can only write a half-word at a time. For a while I was questioning whether OpenOCD was doing this properly but after looking through the OpenOCD debug output and comparing it against what the PM0075 instructions were, I was able to confirm that it did indeed follow the proper steps to do each operation. I also found I was duplicating steps that OpenOCD was already doing so I was able to cut out instructions that weren't helping! So moral of the story: Debug output is your friend!
I struggled getting JLink to work with a STM3240XX and found a statement in the JLink GDB server documentation saying that after loading flash you must issue a "target reset":
"When debugging in flash the stack pointer and the PC are set automatically when the target is reset after the flash download. Without reset after download, the stack pointer and the PC need to be initialized correctly, typically in the .gdbinit file."
When I added a "target reset" in the Run box of the debugger Setup of Eclipse, suddenly everything worked. I did not have this problem with a Kinetis K60.
The document also explains how to manually set the stack pointer and pc directly if you don't want to issue a reset. It may not be the disconnect/connect that solves the problem but the reset.
What i use after the last sentence in the Comannd Tab - 'Run' Commands, is:
symbol-file STM3210CTest/test_rom.elf
thbreak main
continue
The thbreak main sentence is what makes gdb stop at main.
Is there a way to slow down the internet connection to the iPhone Simulator, so as to mimic how the App might react when you are in a slow spot on the cellular network?
How to install Apple’s Network Link Conditioner
These instructions current as of October 2019.
Warning: If you just upgraded to new version of macOS, make sure you install the very latest Network Conditioner (in Additional Tools for Xcode) or it may silently fail; that is, you will turn it on but it won’t throttle anything or drop any packets.
Update: As of Xcode 11, there may be an even simpler way to simulate network conditions on tethered devices; see this blog post. For how to affect simulated devices, continue below, as before.
Install Xcode if you don’t have it.
Open Xcode and go to Xcode › Open Developer Tool › More Developer Tools…
Download Additional Tools for Xcode (matching your current Xcode version)
Open the downloaded disk image and double-click the Network Link Conditioner .prefpane under “Hardware” to install it.
There we go!
Be sure to turn it on. You need to select a profile and enable the network conditioner.
Caveat
This won't affect localhost, so be sure to use a staging server or co-worker's computer to simulate slow network connections to an API you’re running yourself. You may find https://ngrok.com/ helpful in this regard.
"There's an app for that!" ;) Apple provides "Network Link Conditioner" preference pane that does the job quite well.
for Xcode versions prior to 4.3, the pane installer can be found in your Developer folder, e.g. "/Developer/Applications/Utilities/Network Link Conditioner", after installation, if daemon fails to start and you don't want to reboot your machine, just use sudo launchctl load /system/library/launchdaemons/com.apple.networklinkconditioner.plist
if you are already done with Developer folder, you can install the pane as a part of "Hardware IO Tools for Xcode" package available via Mac Dev Center additional downloads section.
Link to download page (you must log in with your Apple ID): https://developer.apple.com/downloads/index.action
(credits to #nverinaud)
An app called SpeedLimit
https://github.com/mschrag/speedlimit
Works great.
chris.
It also worth mentioning that Xcode also has a built in way for devices, not simulator.
Just go 'Devices and Simulator' (cmmd+shift+2)
Select your device
Scroll down til you find 'Device Conditions'
Set your desired profile
Hit Start
To have this working you need to install 'Network Link Conditioner' on your Mac. See steps mention in Alan's answer
I would argue that a slow connection isn't enough to simulate real-work mobile data network behaviour - since there is also much more packet loss, higher latencies and more dropped connections too.
Here is a handy script I found to configure the firewall to emulate these parameters:
http://pmilosev-notes.blogspot.com/2011/02/ios-simulator-testing-over-different.html
#!/bin/sh
if [ "$#" -ne "3" ]
then
echo "Usage:\n$0 <bandwidth in kpbs> <delay in ms> <packet loss ratio>";
exit 1
fi
BW=$1
DELAY=$2
PLR=$3
sudo ipfw pipe 1 config bw ${BW}Kbit/s delay $DELAY plr $PLR
sudo ipfw add 1 pipe 1 all from me to not me
sudo ipfw add 2 pipe 1 all from not me to me
echo "RETURN to stop connection noise"
read
sudo ipfw delete 1
sudo ipfw delete 2
exit 0
Some suggested values you can use:
Scenario
Bw (Kbit)
delay (ms)
pr (ratio)
2.5G mobile
(GPRS)
50
200
3G mobile
1000
200
0.2
VSAT
5000
500
0.2
Busy LAN on VSAT
300
500
0.4
There isn't a direct way to emulate a slow connection, unlike, say, the nice network connection emulator that blackberry developers enjoy. However, since your simulator's connection goes through your computer - you can simply focus on slowing down your computer's connection.
You'll want to achieve two things (depending upon your circumstances):
throttle your bandwidth
increase your latency
Maybe this will point you in right direction:
http://www.macosxhints.com/article.php?story=20080119112509736
There are some good open source solutions, too, but I so can't remember their names.
This question might help: How to throttle network traffic for environment simulation?
You can do it in really device through Xcode(14) settings
Debug -> Induce Device conditions -> Network Link -> select the Network you want