Friday, March 14, 2025

#include <stdlib.h>
#include <unistd.h>
#include <asm/unistd.h>
#include <linux/perf_event.h>
#include <sys/ioctl.h>
#include <fcntl.h>
#include <stdint.h>
// Structure for perf_event_attr
struct perf_event_attr pe;


// need permsiion  on perf_event_open
// to see value ->
// cat /proc/sys/kernel/perf_event_paranoid

//0: Allows access to all users to use perf_event_open for monitoring performance events.
//1: Allows access only to privileged users (typically root) to use perf_event_open.
//2: Disallows access to all users to use perf_event_open

//sudo sysctl kernel.perf_event_paranoid=<new_value>

// Function to initialize and read CPU cycle count
uint64_t read_cpu_cycles() {
    // Initialize perf_event_attr structure
    memset(&pe, 0, sizeof(struct perf_event_attr));
    pe.type = PERF_TYPE_HARDWARE;
    pe.config = PERF_COUNT_HW_CPU_CYCLES;

    // Open the event
    int fd = syscall(__NR_perf_event_open, &pe, 0, -1, -1, 0);
    if (fd == -1) {
        perror("Error opening leader %llx");
        //exit(EXIT_FAILURE);
        return 0;
    }

    // Read the counter
    uint64_t count;
    read(fd, &count, sizeof(uint64_t));

    // Close the event
    close(fd);

    return count;
}

Tuesday, January 9, 2024

Handling Large file - generated

Dealing with Large Symbol Files

nice tool to compress exe or runtime file on linux

use UPX

Tuesday, December 26, 2023

C++ improve your memory allocation

Arena allocation is a C++-only feature that helps you optimize your memory usage and improve performance when working with protocol buffers.

C++ Arena Allocation Guide

Thursday, August 31, 2023

future in c++ some good performance article

https://engineering.fb.com/2015/06/19/developer-tools/futures-for-c-11-at-facebook/

https://github.com/facebook/folly/blob/main/folly/docs/Overview.md

https://twitter.github.io/finagle/guide/Futures.html

Saturday, June 3, 2023

Tuesday, April 4, 2023

Improve GCC build time

Improving Compilation Time of C/C++ Projects

Thursday, March 30, 2023

c++ coding standards (jsf c++)

great pdf with instruction about coding standards

Joint Strike Fighter Air Vehicle C++ Coding Standards

Monday, March 27, 2023

Debugging C++ , with VSCode & GDB command ( improve loading performance tip for heavy projects)

Its all about symbols that loaded into memory in the debug process.

With VScode could takes time just to get into your breakpoint, on huge c++ project , with many so files and dependencies.
sometimes moving with F10 takes time , and looks like vscode screen is freezing.
to fix this issue and get much better vscode debug performance follow the next steps:
add to launch.json file as follow the next section, make sure in the exceptionList you have your brand so file .
the section below prevent loading extra symbols that you don't need to debug.

you can add many so file is the exceptionList separated by semicolon "tttt.so;yyy.so"

"symbolLoadInfo": {
"loadAll": false,
"exceptionList": "libMyShared.so"
},

The next tip with VScode - make sure to close the Local list in the VARIABLES group

GDB

to work with gdb command line make sure all the symbolic will not loaded , the default is ON.

the next parameter control such behavior

in gdb type 'set auto-solib-add off' - disabled loading any symbolic files.

you can start your program

and when your SO files loaded , you can CTRL-C

and use the share command to load your so symbolic file.

share /path/mysofile.so

option 2 : put in your program the next line

__asm__ volatile("int $0x03");

its will break into your gdb and use share command to load your symbolic .

Advanced Debugging with GDB - nice video

enjoy

Yaniv Tzanany

Monday, March 20, 2023

C++ custom debugger view for VisualCode

you can add custom view for debugger.

https://www.cppstories.com/2021/natvis-tutorial/

https://devblogs.microsoft.com/cppblog/debug-visualizers-in-visual-c-2015/

create into your root folder xxx.natvis

make sure in the launch.json to add

            "visualizerFile": "${workspaceFolder}/xxx.natvis",
            "showDisplayString": true,

more sample:

https://learn.microsoft.com/en-us/visualstudio/debugger/create-custom-views-of-native-objects?view=vs-2019

note:

the Name of the class must be full qualified e.g. contain namespace name if exist.

even typedef name should be act as new Name in the natvis file.

enjoy

Yaniv

sample template class:

template<typename T> class MyObject
{
public:
    MyObject() : myVal( 5 ) {}
    T myVal;
};

sample template natvis file:

<?xml version="1.0" encoding="utf-8"?>
<AutoVisualizer xmlns="http://schemas.microsoft.com/vstudio/debugger/natvis/2010">

<Type Name="MyObject&lt;*&gt;">
  <DisplayString>{{myVal = {myVal}}}</DisplayString>
  <Expand>
    <Item Name="[myVal]">myVal</Item>
  </Expand>
</Type>  
</AutoVisualizer>