• blktrace.git
• man blkrawverify
• man verify_blkparse

blkrawverify 和 verify_blkparse 都是 verifies an output file produced by blkparse

blkrawverify

The blkrawverify utility can be used to verify data retrieved via blktrace. It will check for valid event formats, forward progressing sequence numbers and time stamps, also does reasonable checks for other …

• blktrace.git
• man blkparse

The blkparse utility will attempt to combine streams of events for various devices on various CPUs, and produce a formatted output of the event information. Specifically, it will take the (machine-readable) output of the blktrace utility and convert it to a nicely formatted and human-readable form …

• blktrace.git
• man blktrace

blktrace is a block layer IO tracing mechanism which provides detailed information about request queue operations up to user space. There are three major components: a kernel component, a utility to record the i/o trace information for the kernel to user space, and utilities to …

• man btrace
• blktrace.git

btrace can show detailed info about what is happening on a block device io queue. This is valuable for diagnosing and fixing performance or application problems relating to block layer io.

The btrace script provides a quick and easy way to do live tracing of block …

• d0ca268 Initial commit of blktrace

Inital commit of blktrace userspace tools 包含下列几个文件：

    ├── blkparse.c
    ├── blktrace.c
    ├── blktrace.h
    ├── Makefile
    └── README

README

    % blktrace <dev>
    --- run task to generate load to be traced ---
    <SIGINT to kill>
    --- Generates:
        <dev>_dat.[0..ncpus] : Contains binary pdu data
        <dev>_out.[0..ncpus] : Contains binary trace …

• 2056a782f8e7 [PATCH] Block queue IO tracing support (blktrace) as of 2006-03-23
• v2.6.17-rc1 include/linux/blktrace_api.h
• v2.6.17-rc1 block/blktrace.c

blktrace.c 实现了 message 的填充（包括 message header 的构造 - struct blk_io_trace）并通过 relayfs 传递 message 到 userspace；blktrace_api 封装对 __blk_add_trace 的调用，Block IO layer 通过调用这些 APIs …

• include/linux/relay.h
• kernel/relay.c
• Documentation/filesystems/relay.txt

详细的 GUIDE 参考 Documentation/filesystems/relay.txt

A 'relay channel' is a kernel->user data relay mechanism implemented as a set of per-cpu kernel buffers ('channel buffers'), each represented as a regular file ('relay file') in user space. Kernel …

最近想在本子上装个 virtualbox 跑个 winxp，旧本子，一直用的 32 位 Debian，内核经常更新，现在版本是 5.0.0-rc2+

apt install virtualbox virtualbox-dkms 安装完后，建立虚拟机的时候报错，说不能加载 vboxdrv 模块

dkms build

想着可能是因为内核新，所以 dkms 工作没做好，干脆跑一下 dkms build。结果一跑，报错了：

    # dkms build -m virtualbox -v 5.2.24

    Kernel preparation unnecessary for this kernel.  Skipping...

    Building …

• fio HOWTO

I/O engine ioengine=str

Defines how the job issues I/O to the file. The following types are defined: ("libaio/sg/net/netsplice/rdma/rados/rbd/gfapi/gfapi_async" defines engine specific options)

    null
        Doesn't transfer any data, just pretends to. This is mainly used to
        exercise …

• fio HOWTO

Environment variables

Fio also supports environment variable expansion in job files. Any sub-string of the form ${VARNAME} as part of an option value (in other words, on the right of the '='), will be expanded to the value of the environment variable called VARNAME. If no such environment variable …