szaydel

#!/usr/sbin/dtrace -qCs
#define UPPER_THRESHOLD 100

/* See zio.h line 147 or thereabout */
enum zio_priority {
    ZIO_PRIORITY_SYNC_READ,
    ZIO_PRIORITY_SYNC_WRITE,   /* ZIL */
    ZIO_PRIORITY_ASYNC_READ,   /* prefetch */
    ZIO_PRIORITY_ASYNC_WRITE,  /* spa_sync() */
    ZIO_PRIORITY_SCRUB,        /* asynchronous scrub/resilver reads */

mmitchel

I was able to install FreeBSD on GCE in a very direct way, without the hurdles of Qemu, gcutil, and the FreeBSD installer. All are great tools, but I think my apporach is somewhat more suitable for GCE, or at least much simpler. Much of this is well-known practice for installing manually, with some fluff for managing it as a disk image, as well as the few odd networking requirements of GCE (MTU and netmask).



My basic approach is to:

* Use my FreeBSD machine at home to build a self-hosting "rescue" disk image for GCE.

* Start a temporary Linux machine in GCE from a provided image.

jberkus

WITH btree_index_atts AS (
    SELECT nspname, relname, reltuples, relpages, indrelid, relam,
        regexp_split_to_table(indkey::text, ' ')::smallint AS attnum,
        indexrelid as index_oid
    FROM pg_index
    JOIN pg_class ON pg_class.oid=pg_index.indexrelid
    JOIN pg_namespace ON pg_namespace.oid = pg_class.relnamespace
    JOIN pg_am ON pg_class.relam = pg_am.oid
    WHERE pg_am.amname = 'btree'
    ),

rmartinho

Dear C++ library writer,

1. If your library forces me to use new all over, I will hate you.

2. If your library has types with bogus values, I will hate you.

3. If the documentation for your library gets the terminology of its own domain wrong, I will hate you.

4. If I say "My God, it's full of stars!" when I see the function signatures in your library, I will hate you.

ecin

package main

/*
Ping vs Pong: A Gladiatorial Match
Two goroutines enter, only one leaves...
*/

/*
#cgo LDFLAGS: -lprobes -L/usr/local/lib
#include "probes.h"

tsuna

gRPC SSL/TLS cert rotation

Generate a couple key pairs:

openssl req -x509 -newkey rsa:2048 -keyout key1.pem -out cert1.pem -days 42 -nodes
openssl req -x509 -newkey rsa:2048 -keyout key2.pem -out cert2.pem -days 42 -nodes
ln -s key1.pem key.pem
ln -s cert1.pem cert.pem

mitsuhiko

#!/usr/bin/env python
# Quick and dirty demonstration of CVE-2014-0160 by
# Jared Stafford (jspenguin@jspenguin.org)
# Modified so that it finds cookies

import sys
import struct
import socket
import time
import select

seboudry

Latency numbers every programmer should know

L1 cache reference ......................... 0.5 ns
Branch mispredict ............................ 5 ns                     on recent CPU
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 µs
Send 2K bytes over 1 Gbps network ....... 20,000 ns  =  20 µs
SSD random read ........................ 150,000 ns  = 150 µs

Read 1 MB sequentially from memory ..... 250,000 ns = 250 µs 4X memory

andelf

package main

import (

  "log"
	"net/mail"
	"encoding/base64"
	"net/smtp"
	"fmt"
	"strings"

jberkus

WITH table_scans as (
    SELECT relid,
        tables.idx_scan + tables.seq_scan as all_scans,
        ( tables.n_tup_ins + tables.n_tup_upd + tables.n_tup_del ) as writes,
                pg_relation_size(relid) as table_size
        FROM pg_stat_user_tables as tables
),
all_writes as (
    SELECT sum(writes) as total_writes
    FROM table_scans