bobrik

[21:13:21]	[build] dpkg-buildpackage -rfakeroot -us -uc -b
[21:13:21]	[build] dpkg-buildpackage: info: source package bcc
[21:13:21]	[build] dpkg-buildpackage: info: source version 0.3.0-1
[21:13:21]	[build] dpkg-buildpackage: info: source distribution unstable
[21:13:21]	[build] dpkg-buildpackage: info: source changed by Brenden Blanco <[email protected]>
[21:13:21]	[build] dpkg-source --before-build bcc-0.3.0
[21:13:21]	[build] dpkg-buildpackage: info: host architecture amd64
[21:13:22]	[build] fakeroot debian/rules clean
[21:13:22]	[build] dh clean --buildsystem=cmake --parallel
[21:13:22]	[build] dh_testdir -O--buildsystem=cmake -O--parallel

bobrik

#!/usr/bin/perl -w
# Original source: https://lkml.org/lkml/2016/12/7/114
# Changesd to ping the whole 8.8.x.x subnet to produce lots of entries.

my $subnet = '8.8';

use Socket;
use Symbol;
use NetAddr::IP::Lite;

bobrik

[global]
direct=1
runtime=30m
group_reporting
time_based

[randread]
rw=randread
size=1g
bs=4k

bobrik

bobrik

bobrik

Overly aggressive CFS

We're looking at CPU bandwidth control via CFS:

• https://www.kernel.org/doc/Documentation/scheduler/sched-bwc.txt

Reproduction program

Program does number of iterations, in each iteration we burn CPU in small chunks until we get 5ms of real time spent. On each iteration we also print how much

bobrik

Redis KPTI benchmark

Other benchmarks make me sad. People run them in the cloud where VMs can migrate between different hosts on reboots and use old kernels. Here we use bare metal with the same recent kernel to remove extra variables and measure KPTI impact and KPTI impact only.

Setup

• Kernel: 4.14.11

bobrik

{
  "status": "success",
  "data": {
    "resultType": "matrix",
    "result": [
      {
        "metric": {
          "__name__": "node_cpu",
          "colo_id": "28",
          "colo_name": "sea01",

bobrik

{
  "annotations": {
    "list": [
      {
        "builtIn": 1,
        "datasource": "-- Grafana --",
        "enable": true,
        "hide": true,
        "iconColor": "rgba(0, 211, 255, 1)",
        "name": "Annotations & Alerts",

bobrik

{
  "cards": {
    "cardPadding": null,
    "cardRound": null
  },
  "color": {
    "cardColor": "#bf1b00",
    "colorScale": "sqrt",
    "colorScheme": "interpolateRdYlGn",
    "exponent": 0.25,