mratsim

libdispatch efficiency tips

I suspect most developers are using the libdispatch inefficiently due to the way it was presented to us at the time it was introduced and for many years after that, and due to the confusing documentation and API. I realized this after reading the 'concurrency' discussion on the swift-evolution mailing-list, in particular the messages from Pierre Habouzit (who is the libdispatch maintainer at Apple) are quite enlightening (and you can also find many tweets from him on the subject).

• https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170828/date.html
• https://lists.swift.org/pipermail/swift-evolution/Week-of-Mon-20170904/date.html

My take-aways are:

• You should have very few queues that target the global pool. If all these queues are active at once, you will get as many threads running. These queues should be seen as execution contexts in the program (gui, storage, background work, ...) that benefit from executing in parallel.

mratsim

type
  Function = ref object
    stages: seq[Stage]
    output: Parameter
    schedule: FunctionSchedule

  Call = ref object
    function: Function
    params: seq[LuxNode]

mratsim

2019-07-11 Eth2.0 Impl Call 21

---

Nimbus

Core:

• Testnet1 -based on libp2p-daemon, launched this morning, need to adapt the script to start it with a single command (libp2p-daemon not build)

mratsim

/* Generated by Nim Compiler v0.19.6 */
/*   (c) 2018 Andreas Rumpf */
/* The generated code is subject to the original license. */
/* Compiled for: Linux, amd64, gcc */
/* Command for C compiler:
   gcc -c  -w  -I/home/beta/.choosenim/toolchains/nim-0.19.6/lib -o /home/beta/.cache/nim/e12_syntax_revamp_d/e12_syntax_revamp.c.o /home/beta/.cache/nim/e12_syntax_revamp_d/e12_syntax_revamp.c */
#define NIM_NEW_MANGLING_RULES
#define NIM_INTBITS 64

#include "nimbase.h"

mratsim

SKS Keyserver Network Under Attack

This work is released under a Creative Commons Attribution-NoDerivatives 4.0 International License.

Terminological Note

"OpenPGP" refers to the OpenPGP protocol, in much the same way that HTML refers to the protocol that specifies how to write a web page. "GnuPG", "SequoiaPGP", "OpenPGP.js", and others are implementations of the OpenPGP protocol in the same way that Mozilla Firefox, Google Chromium, and Microsoft Edge refer to software packages that process HTML data.

Who am I?

mratsim

ETH Impl call #20

ethereum/eth2.0-pm#51

---

Nimbus team

• Specs:
• most 0.7.1 implemented

mratsim

Eth2.0 implementer's call #19

ethereum/eth2.0-pm#45

Specs:

• 2 PRs pending for 0.7.0 compat

Sync:

• backward sync integrated (request all blocks up to a point)

Networking:

mratsim

ethereum/eth2.0-pm#43

---

Nimbus

• Several people in holidays
• Debugging multithreading issues

Networking:

• Forward and backward sync

mratsim

import posix
import strutils

when defined(macosx):
  const
    libName = "libpcap.dylib"
    defaultIfName* = "en0"
else:
  # where is u_int type defined for pcap.h??

mratsim

import hashes, sets, random, sequtils, times

const IntSize = sizeof(int)

proc randomString(len: Natural): string =
  result = newString(len)
  for c in result.mitems:
    c = rand('a'..'z')

proc sum[T](x: seq[T]): T =