Operating System – Water's Home

Speed up by ignoring std::cout

Posted on May 21, 2019 by admin

Test Code

```
#include <iostream>
```
```
 
```
```
int main(int argc, char *argv[])
```
```
{
```

	//std::cout.setstate(std::ios_base::badbit);

```
	for(int i = 0; i < 100; i ++) {
```
```
		for(int i = 0; i < 100; i ++) {
```
```
			;//std::cout << "" << std::endl;
```
```
		}
```
```
	}
```
```
	return 0;
```
```
}
```

Test it without std::cout

```
root@imx6ul7d:~/tmp# time ./t1_1 
```
```
 
```
```
real    0m0.041s
```
```
user    0m0.020s
```
```
sys     0m0.000s
```

Test it with std::cout, but redirect to /dev/null

root@imx6ul7d:~/tmp# time ./t1_0 > /dev/null

```
 
```
```
real    0m0.096s
```
```
user    0m0.030s
```
```
sys     0m0.030s
```

Test it with std::cout, but set io state

```
root@imx6ul7d:~/tmp# time ./t1_2
```
```
 
```
```
real    0m0.061s
```
```
user    0m0.040s
```
```
sys     0m0.000s
```

Profile : Linux

Posted on May 17, 2019 by admin

Example 1

Add -pg

arm-linux-gnueabihf-g++ -Wall -g -pg hello.cpp -o hello -std=c++17

Test

```
root@imx6ul7d:~# gprof -b hello 
```
```
Flat profile:
```
```
 
```
```
Each sample counts as 0.01 seconds.
```

  %   cumulative   self              self     total

 time   seconds   seconds    calls   s/call   s/call  name

100.00      3.45     3.45        1     3.45     3.45  hehe()

  0.00      3.45     0.00        4     0.00     0.00  std::_Optional_base<std::__cxx11::basic_string<char, std::char_traits<char>, std::allocator<char> > >::_M_is_engaged() const

```
......
```

First Line of Code (Version 2) Notes

Posted on May 6, 2019 by admin

Routes stream to specified buffer

Posted on April 10, 2019 by admin

Developer Command Prompt for VS 2019

```
cl basic_ios_rdbuf.cpp /EHsc
```

MSDN Source Code

```
#include <ios>
```
```
#include <iostream>
```
```
#include <fstream>
```
```
 
```
```
int main( ) 
```
```
{
```
```
   using namespace std;
```
```
   ofstream file( "rdbuf.txt" );
```

   streambuf *x = cout.rdbuf( file.rdbuf( ) );

   cout << "test" << endl; // Goes to file

```
   cout.rdbuf(x);
```
```
   cout << "test2" << endl; //normal
```
```
}
```

IPC Performance : Socket on ARM

Posted on April 10, 2019April 10, 2019 by admin

Test Environment

CPU: Freescale i.MX6UL rev1.1 528 MHz
DRAM: 512 MiB

Test Code

```
#include <stdlib.h>
```
```
#include <sys/types.h>
```
```
#include <sys/socket.h> 
```
```
#include <netinet/in.h>
```
```
#include <errno.h>
```
```
#include <string.h>
```
```
#include <unistd.h>
```
```
#include <fcntl.h>
```
```
 
```
```
#define CLTIP "127.0.0.1"
```
```
#define SRVPORT 10172
```
```
#define MAX_NUM 1024
```
```
 
```
```
int main(int argc, char* argv[])
```
```
{
```
```
	struct timeval tv_sta, tv_end;
```
```
 
```
```
	gettimeofday(&tv_sta, NULL);
```
```
 
```
```
	int i = 0;
```
```
	int total = 1;
```
```
	int is_printf = 1;
```
```
	if (argc > 1) {
```
```
		total = atoi(argv[1]);
```
```
	}
```
```
	if (argc > 2) {
```
```
		is_printf = atoi(argv[2]);
```
```
	}
```
```
 
```
```
	for (i = 0; i < total; i++) {
```
```
 
```

		int clientsock = socket(PF_INET, SOCK_STREAM, 0);

```
		if (clientsock < 0)
```
```
		{
```
```
			printf("socket creation failed\n");
```
```
			exit(-1);
```
```
		}
```
```
		if (is_printf)
```

			printf("socket create successfully.\n");

```
 
```
```
		struct sockaddr_in clientAddr;
```
```
		clientAddr.sin_family = AF_INET;
```

		clientAddr.sin_port = htons((u_short)SRVPORT);

		clientAddr.sin_addr.s_addr = inet_addr(CLTIP);

```
 
```

		int flags = fcntl(clientsock, F_GETFL, 0);

		fcntl(clientsock, F_SETFL, flags | O_NONBLOCK);

```
 
```
```
		int n;
```

		if ((n = connect(clientsock, (struct sockaddr*) & clientAddr, sizeof(struct sockaddr))) < 0)

```
		{
```
```
			if (errno != EINPROGRESS) {
```

				printf("Connect error.IP[%s], port[%d]\n", CLTIP, clientAddr.sin_port);

```
				exit(-1);
```
```
			}
```
```
		}
```
```
 
```
```
		if (n != 0) {
```
```
 
```
```
			fd_set rset, wset;
```
```
			FD_ZERO(&rset);
```
```
			FD_SET(clientsock, &rset);
```
```
			wset = rset;
```
```
			struct timeval tval;
```
```
			tval.tv_sec = 1;
```
```
			tval.tv_usec = 0;
```

			if ((n = select(clientsock + 1, &rset, &wset, NULL, 3 ? &tval : NULL)) == 0) {

				printf("Connect TIMEOUT.IP[%s], port[%d]\n", CLTIP, clientAddr.sin_port);

```
				exit(-1);
```
```
			}
```

			if (FD_ISSET(clientsock, &rset) || FD_ISSET(clientsock, &wset)) {

```
				int error;
```
```
				int len = sizeof(error);
```

				if (getsockopt(clientsock, SOL_SOCKET, SO_ERROR, &error, &len) < 0) {

```
					printf("pending error");
```
```
					exit(-1);
```
```
				}
```
```
			}
```
```
			else {
```

				printf("select error: clientsock not set");

```
				exit(-1);
```
```
			}
```
```
 
```
```
		}
```
```
		fcntl(clientsock, F_SETFL, flags);
```
```
 
```
```
		if (is_printf)
```

			printf("Connect to IP[%s], port[%d]\n", CLTIP, clientAddr.sin_port);

```
 
```

		const char* sendBuf = "{\"signalType\":\"CONFIG\", \"signalData\":[{\"id\":\"CONF_NAME\", \"value\":\"PPS_MChip1\"}]}";

```
		char recvBuf[MAX_NUM] = { 0 };
```
```
 
```
```
		//while(gets(sendBuf) != '\0')
```
```
		{
```

			if (send(clientsock, sendBuf, strlen(sendBuf), 0) == -1)

```
			{
```
```
				printf("send error!\n");
```
```
			}
```
```
			if (is_printf)
```

				printf("send to server:%s\n", sendBuf);

			//memset(sendBuf, 0, sizeof(sendBuf));

```
 
```
```
			{
```
```
				int timeOut = 3000;
```
```
				int nRet = 0;
```
```
				struct timeval timeout;
```
```
				fd_set recvset;
```
```
				FD_ZERO(&recvset);
```
```
				FD_SET(clientsock, &recvset);
```
```
				timeout.tv_sec = timeOut / 1000;
```
```
				timeout.tv_usec = timeOut % 1000;
```

				nRet = select(clientsock + 1, &recvset, 0, 0, &timeout);

```
				if (nRet <= 0)
```
```
				{
```

					printf("clientsock recv select is error!\n");

```
					exit(-1);
```
```
				}
```
```
			}
```
```
 
```

			if (recv(clientsock, recvBuf, MAX_NUM, 0) == -1)

```
			{
```
```
				printf("rev error!\n");
```
```
			}
```
```
			if (is_printf)
```

				printf("receive from server:%s\n", recvBuf);

			if (strcmp(recvBuf, "Goodbye,my dear client!") == 0)

```
			{
```
```
				//break;
```
```
			}
```
```
			memset(recvBuf, 0, sizeof(recvBuf));
```
```
		}
```
```
		close(clientsock);
```
```
 
```
```
	}
```
```
 
```
```
	gettimeofday(&tv_end, NULL);
```
```
 
```

	int total_millisecond = (tv_end.tv_sec * 1000 + tv_end.tv_usec / 1000) - (tv_sta.tv_sec * 1000 + tv_sta.tv_usec / 1000);

	int average_millisecond = (total_millisecond / total);

```
 
```

	printf("total_millisecond : %ld total_nums : %d\n", total_millisecond, total);

	printf("average_millisecond   : %ld\n", average_millisecond);

```
 
```
```
	return 0;
```
```
}
```

Test Result

```
root@imx6ul7d:~/tmp# ./a.out 1 0
```
```
total_millisecond : 13 total_nums : 1
```
```
average_millisecond   : 13
```
```
root@imx6ul7d:~/tmp# ./a.out 10 0
```
```
total_millisecond : 104 total_nums : 10
```
```
average_millisecond   : 10
```
```
root@imx6ul7d:~/tmp# ./a.out 100 0 
```

total_millisecond : 1023 total_nums : 100

```
average_millisecond   : 10
```
```
root@imx6ul7d:~/tmp# ./a.out 1000 0
```

total_millisecond : 10801 total_nums : 1000

```
average_millisecond   : 10
```

Upgrade to Visual Studio 2019 : Build Problems

Posted on April 4, 2019April 4, 2019 by admin

1. std::toupper —> ::toupper

Original Code (It’s OKay in VS2017) :

VS Upgraded :

Code Updated (It’s OKay in VS2019) :

How to expose a local server behind a NAT or firewall to the internet

Posted on April 3, 2019April 3, 2019 by admin

Download FRP Server & Client

Modify frps.ini

[root@VM_0_5_centos frp_0.25.3_linux_amd64]# cat frps.ini

```
[common]
```
```
bind_port = xxxxxx
```
```
dashboard_port = xxxxxx
```
```
dashboard_user = xxxxxxxxxxxxxxxx
```
```
dashboard_pwd = xxxxxxxxxxxxxxxx
```
```
allow_ports = xxxxx-xxxxx
```
```
token = xxxxxxxxxxxxxxxx
```
```
max_pool_count = 10
```
```
pool_count = 3
```

Start frps

[root@VM_0_5_centos frp_0.25.3_linux_amd64]# ./frps -c ./frps.ini

Modify frpc.ini

```
root@imx6ul7d:~/frp# cat frpc.ini 
```
```
[common]
```
```
server_addr = qinuu.com
```
```
server_port = xxxxxx
```
```
token = xxxxxxxxxxxxxxxx
```
```
[ssh]
```
```
type = tcp
```
```
local_ip = 127.0.0.1
```
```
local_port = 22
```
```
remote_port = xxxxxx
```

Start frpc

root@imx6ul7d:~/frp# ./frpc -c ./frpc.ini

Start a systemd service

[root@VM_0_5_centos frp_0.25.3_linux_amd64]# cat /lib/systemd/system/frps.service
[Unit]
Description=Frp Server Service
After=network.target
 
[Service]
Type=simple
User=nobody
Restart=on-failure
RestartSec=5s
ExecStart=/usr/local/frp/frp_0.25.3_linux_amd64/frps -c /usr/local/frp/frp_0.25.3_linux_amd64/frps.ini
 
[Install]
WantedBy=multi-user.targethis
 
[root@VM_0_5_centos frp_0.25.3_linux_amd64]# systemctl start frps
[root@VM_0_5_centos frp_0.25.3_linux_amd64]# systemctl enable frps
[root@VM_0_5_centos frp_0.25.3_linux_amd64]# systemctl status frps

Cross compile wget with openssl for ARM

Posted on March 15, 2019March 15, 2019 by admin

Config OpenSSL

tar xvf openssl-1.1.1b.tar.gz 
cd openssl-1.1.1b/
mkdir __install
./config --prefix=$PWD/__install no-asm shared

Edit Makefile

PLATFORM=linux-armv4
CROSS_COMPILE=arm-linux-gnueabihf-
delete "-m32" "-m64"

Compile OpenSSL

make
make install

Config Wget && Make

tar zxvf wget-1.20.1.tar.gz
cd wget-1.20.1
./configure --prefix=$PWD/__install --host=arm-linux CC=arm-linux-gnueabihf-gcc --with-ssl=openssl --with-libssl-prefix=/root/Downloads/wget_arm/openssl-1.1.1b/__install --without-zlib
make 
make install

./xxx: /usr/lib/libstdc++.so.6: version `GLIBCXX_3.4.22′ not found (required by ./xxx)

Posted on March 15, 2019March 15, 2019 by admin

Copy libstdc++.so.6.0.24 from cross compiler (7.3.1)

cd /usr/lib
mv libstdc++.so.6 libstdc++.so.6.bak
ln -s libstdc++.so.6.0.24 libstdc++.so.6
chmod 777 libstdc++.so.6

Now, it will be like this !

root@imx6ul7d:/usr/lib# ls -al libstdc++.so.6*
lrwxrwxrwx 1 root root      19 Sep 16 23:03 libstdc++.so.6 -> libstdc++.so.6.0.24
-rwxr-xr-x 1 root root 1240644 Sep  9 02:04 libstdc++.so.6.0.21
-rwxrwxrwx 1 root root 9459568 Sep 16 23:35 libstdc++.so.6.0.24
lrwxrwxrwx 1 root root      19 Jan  1  1970 libstdc++.so.6.bak -> libstdc++.so.6.0.21
-rwxr-xr-x 1 root root 9459568 Sep 16 23:11 libstdc++.so.6.bak_24

TensorFlow on Android (Refer to codelabs : tensorflow-for-poets)

Posted on January 23, 2019January 23, 2019 by admin

The google demo is good, but there are some error when you follow it, so I copied and update it.

Install TensorFlow As Normal

```
pip install tensorflow==1.7.1
```

Download Google Demo

git clone https://github.com/googlecodelabs/tensorflow-for-poets-2

```
cd tensorflow-for-poets-2
```

Download TF_Files

wget http://download.tensorflow.org/example_images/flower_photos.tgz

```
tar -xvf flower_photos.tgz -C tf_files
```

Set ARCHITECTURE

```
IMAGE_SIZE=224
```

ARCHITECTURE="mobilenet_0.50_${IMAGE_SIZE}"

Start TensorBoard

tensorboard --logdir tf_files/training_summaries &

Help : retraining script

```
python -m scripts.retrain -h
```

Train

```
python -m scripts.retrain \
```

  --bottleneck_dir=tf_files/bottlenecks \

```
  --how_many_training_steps=500 \
```
```
  --model_dir=tf_files/models/ \
```

  --summaries_dir=tf_files/training_summaries/"${ARCHITECTURE}" \

  --output_graph=tf_files/retrained_graph.pb \

  --output_labels=tf_files/retrained_labels.txt \

```
  --architecture="${ARCHITECTURE}" \
```
```
  --image_dir=tf_files/flower_photos
```

Train with default 4,000 iterations

```
python -m scripts.retrain \
```

  --bottleneck_dir=tf_files/bottlenecks \

  --model_dir=tf_files/models/"${ARCHITECTURE}" \

  --summaries_dir=tf_files/training_summaries/"${ARCHITECTURE}" \

  --output_graph=tf_files/retrained_graph.pb \

  --output_labels=tf_files/retrained_labels.txt \

```
  --architecture="${ARCHITECTURE}" \
```
```
  --image_dir=tf_files/flower_photos
```

Train with Your Own Data

--image_dir= The root folder of the subdirectories which is used as label names by the classification script
This image is copied from google’s codelabs !

The Retrained Model

```
tf_files/retrained_graph.pb
```
```
tf_files/retrained_labels.txt
```

Test

(venv) water@water-G11CD:~/tensorflow-for-poets-2$ python -m scripts.label_image     --graph=tf_files/retrained_graph.pb      --image=tf_files/flower_photos/daisy/21652746_cc379e0eea_m.jpg

```
 
```

2019-01-23 14:13:50.234939: I tensorflow/core/platform/cpu_feature_guard.cc:140] Your CPU supports instructions that this TensorFlow binary was not compiled to use: AVX2 FMA

```
 
```
```
Evaluation time (1-image): 0.094s
```
```
 
```
```
daisy (score=0.99938)
```
```
sunflowers (score=0.00033)
```
```
dandelion (score=0.00028)
```
```
roses (score=0.00000)
```
```
tulips (score=0.00000)
```

Now, Prepare for Android

Install PILLOW

```
pip install PILLOW
```

Convert the model to TFLite format

```
IMAGE_SIZE=224
```

toco   --input_file=tf_files/retrained_graph.pb   --output_file=tf_files/optimized_graph.lite   --input_format=TENSORFLOW_GRAPHDEF   --output_format=TFLITE   --input_shape=1,${IMAGE_SIZE},${IMAGE_SIZE},3   --input_array=input   --output_array=final_result   --inference_type=FLOAT   --input_data_type=FLOAT

The TFLite Model

```
tf_files/optimized_graph.lite
```

Install AndroidStudio

unzip android-studio-ide-182.5199772-linux.zip

```
cd android-studio/
```
```
cd bin/
```
```
./studio.sh
```

Maybe You Need to Set Proxy

If you use lantern, you can do it like this!

Open Project

Open an existing Android Studio project

Choose android/tflite

Gradle Sync, YES

Build, Make Project

android/tflite/app/build/outputs/apk/debug/app-debug.apk

Test on Your Phone

Add your model files to the project, and then Make Project, Test Again

cp tf_files/optimized_graph.lite android/tflite/app/src/main/assets/graph.lite

cp tf_files/retrained_labels.txt android/tflite/app/src/main/assets/labels.txt

Test Code

Test it without std::cout root@imx6ul7d:~/tmp# time ./t1_1 real 0m0.041suser 0m0.020ssys 0m0.000s

Test it with std::cout, but redirect to /dev/null root@imx6ul7d:~/tmp# time ./t1_0 > /dev/null real 0m0.096suser 0m0.030ssys 0m0.030s

Test it with std::cout, but set io state root@imx6ul7d:~/tmp# time ./t1_2 real 0m0.061suser 0m0.040ssys 0m0.000s

Example 1

Add -pg arm-linux-gnueabihf-g++ -Wall -g -pg hello.cpp -o hello -std=c++17

Developer Command Prompt for VS 2019

MSDN Source Code

Test Environment

Test Code

Test Result

1. std::toupper —> ::toupper

Original Code (It’s OKay in VS2017) :

VS Upgraded :

Code Updated (It’s OKay in VS2019) :

Modify frps.ini

Start frps

Modify frpc.ini

Start frpc

Start a systemd service

Config OpenSSL

Edit Makefile

Compile OpenSSL

Config Wget && Make

Copy libstdc++.so.6.0.24 from cross compiler (7.3.1)

Now, it will be like this !

Install TensorFlow As Normal

Download Google Demo

Download TF_Files

Set ARCHITECTURE

Start TensorBoard

Help : retraining script

Train

Train with default 4,000 iterations

Train with Your Own Data

The Retrained Model

Test

Now, Prepare for Android

Install PILLOW

Convert the model to TFLite format

The TFLite Model

Install AndroidStudio

Maybe You Need to Set Proxy

Open Project

Open an existing Android Studio project

Choose android/tflite

Gradle Sync, YES

Build, Make Project

Test on Your Phone

Add your model files to the project, and then Make Project, Test Again

Test it without std::cout

root@imx6ul7d:~/tmp# time ./t1_1

real 0m0.041s
user 0m0.020s
sys 0m0.000s

Test it with std::cout, but redirect to /dev/null

root@imx6ul7d:~/tmp# time ./t1_0 > /dev/null

real 0m0.096s
user 0m0.030s
sys 0m0.030s

Test it with std::cout, but set io state

root@imx6ul7d:~/tmp# time ./t1_2

real 0m0.061s
user 0m0.040s
sys 0m0.000s

Add -pg

arm-linux-gnueabihf-g++ -Wall -g -pg hello.cpp -o hello -std=c++17