kmalloc

区块链是分布式的共识账本, 网络中节点众多, 各节点达成共识需要复杂的协议交互(POW 算哈希/POS 投票), 导致系统整体并发能力低下, 无法支持大规模大范围应用(TPS极其低), 拥挤的结果是区块空间异常昂贵, 解决的方法是减少底层 transaction 数量, 把部分计算和存储移到线下.

state channel

bitcoin 上的闪电网络采取的方案, 基本思路是交互双方很多的中间交易是不必全部放到区块链中的, 此时可以通过把钱放到一个合约里面, 线下双方双签维护金额的变化即可, 无需其它无关人士来参与并协调达成共识, 具体例子参考[5].

kmalloc

Understanding the Memory Layout of Linux Executables

Required tools for playing around with memory:

• hexdump
• objdump
• readelf
• xxd
• gcore

kmalloc

/*
 * Displays linux /proc/pid/stat in human-readable format
 *
 * Build: gcc -o procstat procstat.c
 * Usage: procstat pid
 *        cat /proc/pid/stat | procstat
 *
 * Homepage: http://www.brokestream.com/procstat.html
 * Version : 2009-03-05
 *

kmalloc

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kmalloc

#include <sched.h>
#include <stdio.h>
#include <stdlib.h>

#include <errno.h>
#include <poll.h>
#include <string.h>
#include <fcntl.h>

#include <unistd.h>

kmalloc

#include <string>
#include <string.h>

#include <map>
#include <vector>
#include <iostream>

#include <assert.h>

const int OP_MAX = 9;

kmalloc

int64_t ipow(int32_t base, uint8_t exp) {
    static const uint8_t highest_bit_set[] = {
        0, 1, 2, 2, 3, 3, 3, 3,
        4, 4, 4, 4, 4, 4, 4, 4,
        5, 5, 5, 5, 5, 5, 5, 5,
        5, 5, 5, 5, 5, 5, 5, 5,
        6, 6, 6, 6, 6, 6, 6, 6,
        6, 6, 6, 6, 6, 6, 6, 6,
        6, 6, 6, 6, 6, 6, 6, 6,
        6, 6, 6, 6, 6, 6, 6, 255, // anything past 63 is a guaranteed overflow with base > 1