Brendan Gregg

JULY 2, 2021

biolatency Disk I/O latency histogram heat map. runqlat CPU scheduler latency heat map. This is thinking like a sysadmin who installs and maintains software, and not like a programmer who codes everything. Then, having discovered everything is C or Python, some rewrite it all in a different language. BPF up and running!

Latency 145

Latency Cache Energy Systems 145

Brendan Gregg

JULY 2, 2021

biolatency Disk I/O latency histogram heat map 5. runqlat CPU scheduler latency heat map 10. They need constant updates to keep working across different software versions. The problems I'm describing are specific to BPF software and kernel tracing. execsnoop New processes (via exec(2)) table 2. patch to Linux 5.12.

Open Source 40

Open Source Latency Cache Energy 40

Brendan Gregg

SEPTEMBER 25, 2021

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. As a Xen guest, this profile was gathered using perf(1) and the kernel's software cpu-clock soft interrupts, not the hardware NMI. As (C) looked like a kernel rebuild, I started with (D) and (E). ## 5. us on Centos and 0.68

Speed 126

Speed Java AWS Virtualization 126

The Netflix TechBlog

AUGUST 29, 2023

In 2010, however, nearly none of it existed: the CNCF wasn’t formed until 2015! Second, we’ve moved from a Java-only environment to a Polyglot one: we now also support node.js , Python , and a variety of OSS and off the shelf software. Today we have a wealth of tools, both OSS and commercial, all designed for cloud-native environments.

Traffic 220

Traffic Latency Cloud C++ 220

Brendan Gregg

SEPTEMBER 25, 2021

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. As a Xen guest, this profile was gathered using perf(1) and the kernel's software cpu-clock soft interrupts, not the hardware NMI. As (C) looked like a kernel rebuild, I started with (D) and (E). ## 6. us on Centos and 0.68

Speed 40

Speed Java AWS Virtualization 40

Brendan Gregg

SEPTEMBER 25, 2021

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. As a Xen guest, this profile was gathered using perf(1) and the kernel's software cpu-clock soft interrupts, not the hardware NMI. As (C) looked like a kernel rebuild, I started with (D) and (E). Ubuntu is 5x slower.

Speed 52

Speed Java AWS Virtualization 52

Brendan Gregg

AUGUST 8, 2017

TABLE OF EXP(-T/C) FOR T = 5 SEC. EXPFF: EXP 0.920043902 ;C = 1 MIN EXP 0.983471344 ;C = 5 MIN EXP 0.994459811 ;C = 15 MIN. I generated this using my offcputime tool from [bcc] (this tool needs eBPF features from Linux 4.8+), and my [flame graph] software: #./bcc/tools/offcputime.py Yes, I'd say so.

Latency 111

Latency Metrics C++ Systems 111