murongruomeng / sponge

CS144 Lab.

For build prereqs, see the CS144 VM setup instructions.

进度

• lab0: networking warmup
• lab1: stitching substrings into a byte stream
• lab2: the TCP receiver
• lab3: the TCP sender
• lab4: the TCP connection
• lab5: the network interface
• lab6: the IP router
• lab7: putting it all together

碎碎念

目前实现了直到 lab4 的所有内容，后续看情况补全 lab5 和 lab6 的代码。

目前可以在此拓展的有：

• 添加快速重传
• 添加 Tahoe 或者 Reno
• 添加 SACK
• 实现 ACK 捎带

个人机器的配置：

• Ubuntu 20.04.3 LTS
• Intel(R) Core(TM) i7-10710U CPU @ 1.10GHz × 12

目前的性能，由于我实现的 byte_stream 性能问题，benchmark 结果为：

CPU-limited throughput                : 0.39 Gbit/s
CPU-limited throughput with reordering: 0.37 Gbit/s

若替换为讲义中提到的高效 byte_stream，结果为：

CPU-limited throughput                : 3.02 Gbit/s
CPU-limited throughput with reordering: 2.44 Gbit/s

后续研究透彻后会将修改后的 byte_stream 补上。

已优化 byte_stream 具体性能，见下：

• 优化 byte_stream 实现

最终优化后的性能如下：

CPU-limited throughput                : 4.64 Gbit/s
CPU-limited throughput with reordering: 3.61 Gbit/s

Sponge quickstart

To set up your build directory:

$ mkdir -p <path/to/sponge>/build
$ cd <path/to/sponge>/build
$ cmake ..

Note: all further commands listed below should be run from the build dir.

To build:

$ make

You can use the -j switch to build in parallel, e.g.,

$ make -j$(nproc)

To test (after building; make sure you've got the build prereqs installed!)

$ make check_labN *(replacing N with a checkpoint number)*

The first time you run make check_lab..., it will run sudo to configure two TUN devices for use during testing.

build options

You can specify a different compiler when you run cmake:

$ CC=clang CXX=clang++ cmake ..

You can also specify CLANG_TIDY= or CLANG_FORMAT= (see "other useful targets", below).

Sponge's build system supports several different build targets. By default, cmake chooses the Release target, which enables the usual optimizations. The Debug target enables debugging and reduces the level of optimization. To choose the Debug target:

$ cmake .. -DCMAKE_BUILD_TYPE=Debug

The following targets are supported:

• Release - optimizations
• Debug - debug symbols and -Og
• RelASan - release build with ASan and UBSan
• RelTSan - release build with ThreadSan
• DebugASan - debug build with ASan and UBSan
• DebugTSan - debug build with ThreadSan

Of course, you can combine all of the above, e.g.,

$ CLANG_TIDY=clang-tidy-6.0 CXX=clang++-6.0 .. -DCMAKE_BUILD_TYPE=Debug

Note: if you want to change CC, CXX, CLANG_TIDY, or CLANG_FORMAT, you need to remove build/CMakeCache.txt and re-run cmake. (This isn't necessary for CMAKE_BUILD_TYPE.)

other useful targets

To generate documentation (you'll need doxygen; output will be in build/doc/):

$ make doc

To format (you'll need clang-format):

$ make format

To see all available targets,

$ make help