Category: Computer Science

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NFSlicer: Data Movement Optimizationfor Shallow Network Functions

最近一直在想网络SmartNIC延时的问题，发现Alex发过这篇,差不多是NSDI23的水平了。NF是用于抽象firewall/load balencer的函数，这些函数的语义会被记录在SmartNIC上。同时做一些offload的操作。这块陈昂做的很多。

传统的NIC只会做hardwired处理器操作，如TSO/LRO/checksum，用SmartNIC很自然就想到先抽象这些操作为network function，问题卷到现在演变成了谁能把serverless/ML的函数放在SmartNIC上更多，谁就顶会。

用一种SmartNIC+NIC offload pipeline的方式,把slice&splice 做的更低时延,但是这有个条件,绝大多数NF都是shallow的情况, 否则tail latency for pipeline会变得异常高.

他们觉得用上了CAT+DDIO的 private caches, LLC, and memory 都还不是bottleneck, 重在以下TTL的pipeline数据通路.

Reference

  1. AlNiCo: SmartNIC-accelerated Contention-aware Request Scheduling for Transaction Processing
  2. Automated SmartNIC Offloading Insights for Network Functions
  3. https://borispis.github.io/files/2022-nicmem-slides.pdf
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IOring Windows at first sight and migration to `monoio`

最近在和LemonHX一起写个跨平台下载器，想要的是个延时确定的协程调度器，然后我们就看上了字节开源的monoio，准备贡献一波Windows部分。

主要需要跨平台抽象的部分已经写好了, GAT 刚进主线, 其实感觉贡献这个更经济一点. 字节内好像也没有开始用这个, 只是做了点测试.

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First-generation Memory Disaggregation for Cloud Platforms @Arxiv

CXL disaggregation because:

  1. Memory inefficiency: s platform-level memory stranding
  2. Current cloud vendor try on memory disaggregation: require no modifications to
    customer workloads or the guest OS./ the system
    must be compatible with virtualization acceleration techniques/ the system must be available as
    commodity hardware.

Continue reading "First-generation Memory Disaggregation for Cloud Platforms @Arxiv"

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Encountering `::signbit` stuff not passing to `math.h` in MacOS 12.4

TL;DR

/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:317:9: error: no member named 'signbit' in the global namespace
using ::signbit;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:318:9: error: no member named 'fpclassify' in the global namespace
using ::fpclassify;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:319:9: error: no member named 'isfinite' in the global namespace
using ::isfinite;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:320:9: error: no member named 'isinf' in the global namespace
using ::isinf;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:321:9: error: no member named 'isnan' in the global namespace
using ::isnan;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:322:9: error: no member named 'isnormal' in the global namespace
using ::isnormal;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:323:9: error: no member named 'isgreater' in the global namespace
using ::isgreater;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:324:9: error: no member named 'isgreaterequal' in the global namespace
using ::isgreaterequal;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:325:9: error: no member named 'isless' in the global namespace
using ::isless;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:326:9: error: no member named 'islessequal' in the global namespace
using ::islessequal;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:327:9: error: no member named 'islessgreater' in the global namespace
using ::islessgreater;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:328:9: error: no member named 'isunordered' in the global namespace
using ::isunordered;
      ~~^
/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/cmath:329:9: error: no member named 'isunordered' in the global namespace
using ::isunordered;
      ~~^

When I was compiling LLVM recently I found this, it may be because my CommandLineTool is outdated as described in stackoverflow. And I reinstalled it with following code added.

using ::signbit _LIBCPP_USING_IF_EXISTS;
using ::fpclassify _LIBCPP_USING_IF_EXISTS;
using ::isfinite _LIBCPP_USING_IF_EXISTS;
using ::isinf _LIBCPP_USING_IF_EXISTS;
using ::isnan _LIBCPP_USING_IF_EXISTS;
using ::isnormal _LIBCPP_USING_IF_EXISTS;
using ::isgreater _LIBCPP_USING_IF_EXISTS;
using ::isgreaterequal _LIBCPP_USING_IF_EXISTS;
using ::isless _LIBCPP_USING_IF_EXISTS;
using ::islessequal _LIBCPP_USING_IF_EXISTS;
using ::islessgreater _LIBCPP_USING_IF_EXISTS;
using ::isunordered _LIBCPP_USING_IF_EXISTS;
using ::isunordered _LIBCPP_USING_IF_EXISTS;

_LIBCPP_USING_IF_EXISTS is defined as # define _LIBCPP_USING_IF_EXISTS __attribute__((using_if_exists)), simply pass if no defined in the global namespace.

Then the following code output error

using _Lim = numeric_limits<_IntT>;

add another header in 

#include <limits>

Then comes to the std::isnan using bypassing no definition error in llvm/lib/Support/NativeFormatting.cpp.

error: expected unqualified-id for std::isnan(N)

just drop the std::

The full formula for riscv-rvv-llvm is located in https://github.com/victoryang00/homebrew-riscv, if anything above happens, do as the above specifies.