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Babak Farrokhi farrokhi

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farrokhi / hugepages_settings.sh
Created January 19, 2020 11:14
Calculate recommended value for HugePages/HugeTLB in Linux
#!/bin/bash
#
# hugepages_settings.sh
#
# Linux bash script to compute values for the
# recommended HugePages/HugeTLB configuration
#
# Note: This script does calculation for all shared memory
# segments available when the script is run, no matter it
# is an Oracle RDBMS shared memory segment or not.
@farrokhi
farrokhi / vim-headers.md
Created January 19, 2020 11:14
vim header file for text documents with proper line-breaking

Text file with hard line-breaks:

# vim:ts=4:sw=4:tw=79:wm=2

Golang source files with proper tab and spacing:

// vim:noet:noai:ts=4:sw=4
@farrokhi
farrokhi / mem_swap_linux.md
Created July 17, 2019 12:18
memory usage and swap investigation in linux 
grep -A1 Normal  /proc/zoneinfo  ; echo "--"; sysctl vm.min_free_kbytes ; echo "--"; numactl -H | grep free
@farrokhi
farrokhi / autotune.py
Created May 19, 2019 11:24
FreeBSD autotuning (loader.conf and sysctl.conf)
#!/usr/local/bin/python
"""
Autotuning program.
Garrett Cooper, December 2011
Example:
autotune.py --conf loader \
--kernel-reserved=2147483648 \
--userland-reserved=4294967296
@farrokhi
farrokhi / best-mirror.sh
Last active November 10, 2022 05:35 — forked from lox/mirror_test.sh
A shell script to select the fastest freebsd-update mirror
#!/bin/sh
# best-mirror.sh
#
# Domesticaed for FreeBSD by Babak Farrokhi (farrokhi@FreeBSD.org)
#
# This script finds the fastest freebsd-update mirror based on
# data transfer rates from cURL.
#
# Note: I used a static list of mirrors, which is not the best way to
@farrokhi
farrokhi / str-perf-test.py
Last active August 6, 2018 15:38
comparing performance of various string concatenation methods in python
from functools import wraps
import pickle
from random import randint, choice
import string
import pathlib
import time
import sys
big_list = [] # our huge list of tuples
cache_file = "test-data-cache.pickle"
@farrokhi
farrokhi / freebsd-ntpd.md
Created June 18, 2018 14:41
Bind FreeBSD ntpd to given IP address

In order to avoid FreeBSD ntpd listen on wildcard interface, add following lines to /etc/ntp.conf:

interface ignore wildcard
interface listen 10.0.0.1
@farrokhi
farrokhi / cscope.md
Created May 30, 2018 07:40
Setting up cscope for a (large) C project

build/update database:

cd $PROJ_DIR
find . -path .git -path .svn -prune -o -name "*.[ch]" > cscope.files
cscope -bqk

browse code:

cscope -d
@farrokhi
farrokhi / dnskey-result.txt
Last active October 20, 2017 11:10
Sad state of DNSSEC adoption with top domains
#
# The output from my check-dnskey.sh script that requests DNSKEY record
# from top 100 domain names and prints the key if there was any.
# last updated on 2017-oct-20
#
google.com NO
youtube.com NO
facebook.com NO
baidu.com NO
wikipedia.org NO
@farrokhi
farrokhi / freebsd-ddb.md
Last active January 19, 2020 11:22
Using FreeBSD Text Dumps

If you need to debug a panic on a remote FreeBSD system, but don't want to transfer large coredumps, and can't afford the downtime caused by KDB interrupting the boot process, a text dump may be the answer. textdump(4) is the kernel dump facility, which allows you to see the crash information in a text format. It also allows for configuration of exactly what information is captured, by scripting input as if you were at the KDB prompt on the console.

Textdump has certain requirements. First, you must be running FreeBSD 7.1 or higher, and your kernel config must include the following options.

options DDB
options KDB
options KDB_UNATTENDED
options KDB_TRACE