• go die

    自私还好, 双标更烦

  • install systemtap

    http://r00tkit.me/?p=59

    	#!/bin/bash
    WEB="http://debuginfo.centos.org/6/i386/"
    RELEASE=`uname -r`
    MACHINE=`uname -m`
    PKG1="kernel-debuginfo-$RELEASE.rpm"
    PKG2="kernel-debuginfo-common-$MACHINE-$RELEASE.rpm"
    wget $WEB$PKG1
    wget $WEB$PKG2
    #Build Downloaded debuginfo packages
    rpm -Uhv kernel-debuginfo-*.rpm
    #Install systemtap and kernel-developemnt packages
    yum install systemtap kernel-devel
    
  • kafka中Server返回的correlationID

    原来kafka server返回的correlationID并不是对应的request中的, 而是依次增加的?

    哦, 搞错了. 是对应request里面的.

  • golang里面string是传值还是传引用

    结论: 传值, 会copy一份新数据

    package main
    
    import "fmt"
    
    func byval(q string) {
    	fmt.Printf("3. byval -- q %T: &q=%p q=%v\n", q, &q, q)
    	q = "xyz"
    	fmt.Printf("4. byval -- q %T: &q=%p q=%v\n", q, &q, q)
    }
    
    func main() {
    	i := "abcd"
    	fmt.Printf("1. main  -- i  %T: &i=%p i=%v\n", i, &i, i)
    	p := i
    	byval(p)
    	fmt.Printf("5. main  -- p %T: &p=%p p=%v\n", p, &p, p)
    	fmt.Printf("6. main  -- i  %T: &i=%p i=%v\n", i, &i, i)
    }
    
    % go run a.go
    1. main  -- i  string: &i=0xc42000a2e0 i=abcd
    3. byval -- q string: &q=0xc42000a330 q=abcd
    4. byval -- q string: &q=0xc42000a330 q=xyz
    5. main  -- p string: &p=0xc42000a320 p=abcd
    6. main  -- i  string: &i=0xc42000a2e0 i=abcd
    
  • changetime和modifytime的区别

    https://stackoverflow.com/questions/3385203/regarding-access-time-unix

    The stat(2) structure keeps track of all the file date/times:

       struct stat {
           dev_t     st_dev;     /* ID of device containing file */
           ino_t     st_ino;     /* inode number */
           mode_t    st_mode;    /* protection */
           nlink_t   st_nlink;   /* number of hard links */
           uid_t     st_uid;     /* user ID of owner */
           gid_t     st_gid;     /* group ID of owner */
           dev_t     st_rdev;    /* device ID (if special file) */
           off_t     st_size;    /* total size, in bytes */
           blksize_t st_blksize; /* blocksize for file system I/O */
           blkcnt_t  st_blocks;  /* number of 512B blocks allocated */
           time_t    st_atime;   /* time of last access */
           time_t    st_mtime;   /* time of last modification */
           time_t    st_ctime;   /* time of last status change */
       }; st_atime is the access time, updated on read(2) calls (and probably also when open(2) opens a file for reading) -- it is NOT updated when files are read via mmap(2). (Which is why I assume open(2) will mark the access time.)
    

    st_mtime is the data modification time, either via write(2) or truncate(2) or open(2) for writing. (Again, it is NOT updated when files are written via mmap(2).)

    st_ctime is the metadata modification time: when any of the other data in the struct stat gets modified.

    You can change the timestamps on files with utime(2):

       struct utimbuf {
           time_t actime;       /* access time */
           time_t modtime;      /* modification time */
       }; Note you can only change the access time and (data) modification time. You can set either of these to arbitrary times, but the ctime is going to be set to the current time -- because you changed the metadata for the file.
    

    There is no create time in this structure, so it’s not possible to find out when a file was created directly from the system.

    If you really need to know the create time, you can narrow it down to a range by looking at your backups – assuming the file you’re interested in has been backed up, along with its metadata.

  • mmap的两篇文章

    http://blog.csdn.net/streetlight8023/article/details/42168403 http://0xffffff.org/2017/05/01/41-linux-io/ mmap和磁盘读写的两篇文章, 不过还是没明白为啥堆外内存小的时候, ES使用mmap index storage会有大量磁盘读写

  • mail中的Content-Transfer-Encoding定义和用法

    python发送邮件时出现乱码, 搜索了一下可以通过更改Content-Transfer-Encoding定义解决.

    msg = MIMEText(None, "plain")
    msg.replace_header('content-transfer-encoding', 'quoted-printable')
    msg.set_payload(content, 'utf-8')
    

    https://stackoverflow.com/questions/25710599/content-transfer-encoding-7bit-or-8-bit

    https://www.w3.org/Protocols/rfc1341/5_Content-Transfer-Encoding.html

  • vm

    https://www.kernel.org/doc/Documentation/sysctl/vm.txt留着后面看

  • 可是

    可是, 我看到微信有消息, 还是希望是你的.

  • 在身边

    happy birthday

    看到这张照片好开心, 有种”一直在身边”的感觉.