patricksuo

LInux

Three system configuration parameters must be set to support a large number of open files and TCP connections with large bursts of messages. Changes can be made using the /etc/rc.d/rc.local or /etc/sysctl.conf script to preserve changes after reboot.

1. /proc/sys/fs/file-max: The maximum number of concurrently open files.

fs.file-max = 1000000

2. /proc/sys/net/ipv4/tcp_max_syn_backlog: Maximum number of remembered connection requests, which are still did not receive an acknowledgment from connecting client. The default value is 1024 for systems with more than 128Mb of memory, and 128 for low memory machines.

net.ipv4.tcp_max_syn_backlog = 3240000

3. /proc/sys/net/core/somaxconn: Limit of socket listen() backlog, known in userspace as SOMAXCONN. Defaults to 128.

net.core.somaxconn = 3240000

patricksuo

[Names]
count=2
name1=Solarized Dark
name0=Solarized Light
[Solarized Light]
text(bold)=586e75
magenta(bold)=6c71c4
text=657b83
white(bold)=fdf6e3
green=859900

patricksuo

Effective Modern CMake

Getting Started

For a brief user-level introduction to CMake, watch C++ Weekly, Episode 78, Intro to CMake by Jason Turner. LLVM’s CMake Primer provides a good high-level introduction to the CMake syntax. Go read it now.

After that, watch Mathieu Ropert’s CppCon 2017 talk Using Modern CMake Patterns to Enforce a Good Modular Design (slides). It provides a thorough explanation of what modern CMake is and why it is so much better than “old school” CMake. The modular design ideas in this talk are based on the book [Large-Scale C++ Software Design](https://www.amazon.de/Large-Scale-Soft

patricksuo

Latency Comparison Numbers
--------------------------
L1 cache reference                           0.5 ns
Branch mispredict                            5   ns
L2 cache reference                           7   ns                      14x L1 cache
Mutex lock/unlock                           25   ns
Main memory reference                      100   ns                      20x L2 cache, 200x L1 cache
Compress 1K bytes with Zippy             3,000   ns        3 us
Send 1K bytes over 1 Gbps network       10,000   ns       10 us
Read 4K randomly from SSD*             150,000   ns      150 us          ~1GB/sec SSD

patricksuo

#!/usr/bin/env python
#
# USAGE:    dotnet-mapgen [-h] {generate,merge} PID
#
# In generate mode, this tool reads the /tmp/perfinfo-PID.map file generated
# by the CLR when running with COMPlus_PerfMapEnabled=1, and finds all load
# events for managed assemblies. For each managed assembly found in this way,
# the tool runs crossgen to generate a symbol mapping file (akin to debuginfo).
#
# In merge mode, this tool finds the load address of each managed assembly in

patricksuo

diff --git a/src/scripts/genXplatLttng.py b/src/scripts/genXplatLttng.py
index bacf034..3d40d77 100644
--- a/src/scripts/genXplatLttng.py
+++ b/src/scripts/genXplatLttng.py
@@ -407,8 +407,25 @@ def generateLttngTpProvider(providerName, eventNodes, allTemplates):
     for eventNode in eventNodes:
         eventName    = eventNode.getAttribute('symbol')
         templateName = eventNode.getAttribute('template')
+
+        template = allTemplates[templateName] if templateName else None

patricksuo

# download latest libevent2 and tmux sources, and extract them somewhere
# (thx bluejedi for tip on latest tmux URL)
#
# at the time of writing:
# https://github.com/downloads/libevent/libevent/libevent-2.0.21-stable.tar.gz
# http://sourceforge.net/projects/tmux/files/latest/download?source=files
# 

# install deps
yum install gcc kernel-devel make ncurses-devel

patricksuo

[unix_http_server]
file=/tmp/supervisor.sock                       ; path to your socket file

[supervisord]
logfile=/var/log/supervisord/supervisord.log    ; supervisord log file
logfile_maxbytes=50MB                           ; maximum size of logfile before rotation
logfile_backups=10                              ; number of backed up logfiles
loglevel=error                                  ; info, debug, warn, trace
pidfile=/var/run/supervisord.pid                ; pidfile location
nodaemon=false                                  ; run supervisord as a daemon