Brendan Gregg

JULY 4, 2021

I summarized these topics and more as a plenary conference talk, including my own predictions (as a senior performance engineer) for the future of computing performance, with a focus on back-end servers. Ford, et al., “TCP

Performance 52

Performance Latency Hardware Storage 52

SQL Performance

FEBRUARY 22, 2021

I would like to share a couple of recent examples that help illustrate how using deprecated SQL Server features continues to bite us. The system table sys.sysprocesses was replaced way back in SQL Server 2005 by a set of dynamic management views (DMVs), most notably sys.dm_exec_requests , sys.dm_exec_sessions , and sys.dm_exec_connections.

Latency 57

Latency Servers Monitoring Systems 57

Percona

JANUARY 24, 2023

Some of the built-in features ( wal_compression ) have been there since 2016, and almost all backup tools do the WAL compression before taking it to the backup repository. Individual processes generate WAL records, and latency is very crucial for transactions. So it has never been part of the general advice for optimizations.

Database 114

Database Benchmarking Open Source Latency 114

Alex Russell

MARCH 6, 2021

Back in 2016, I gave a talk outlining the causes and effects of the terrible performance of web apps built using popular tools on the fastest-growing device segment: low-end to mid-range Android phones. In 2016, Jio swept over the subcontinent like a monsoon dropping a torrent of 4G infrastructure and free data rather than rain.

Performance 124

Performance Network Cache Metrics 124

KeyCDN

JANUARY 31, 2019

With Bucharest being the capital and largest city of Romania, it makes for a great edge server location. The next closest active POP location to Bucharest was Istanbul which was still almost 900km away; this distance adds up in terms of latency. As of 2016, Bucharest alone had a population of over 1.83 million people.

Internet 48

Internet Internet Ecommerce Speed 48

KeyCDN

OCTOBER 24, 2018

With Helsinki being the capital and most populous municipality of Finland, it makes for a great edge server location. Although both countries are relatively close to one another, they are separated by a distance of approximately 500km, which adds up in terms of latency. As of 2016, there were just over 5.1 penetration rate.

Internet 48

Internet Internet Speed Network 48

Brendan Gregg

OCTOBER 8, 2018

Screenshot: tracing read latency for PID 181: # bpftrace -e 'kprobe:vfs_read /pid == 30153/ { @start[tid] = nsecs; } kretprobe:vfs_read /@start[tid]/ { @ns = hist(nsecs - @start[tid]); delete(@start[tid]); }'. Back then I could already tell if disks were seeking by interpreting iostat(1) output: seeing high disk latency but small I/O.

C++ 110

C++ Virtualization Programming Latency 110

Alex Russell

MAY 9, 2022

This is a complex topic, but to borrow from a recent post , web performance expands access to information and services by reducing latency and variance across interactions in a session, with a particular focus on the tail of the distribution (P75+). Consistent performance matters just as much as low average latency.

Performance 86

Performance Latency Metrics Engineering 86

SQL Performance

APRIL 8, 2019

These AMD EPYC processors have a number of advantages for SQL Server workloads, as I will explain in this article. This 14nm first-generation AMD EPYC 7551 processor has 32 cores and 64 threads, and it works in one or two-socket servers. This makes it a good choice for many SQL Server workloads, especially DW workloads.

Azure 42

Azure Virtualization Storage Benchmarking 42

CSS - Tricks

APRIL 1, 2021

Redirects are often pretty light in terms of the latency that they add to a website, but they are an easy first thing to check, and they can generally be removed with little effort. I’m going to update my referenced URL to the new site to help decrease latency that adds drag to the initial page load.

Cache 92

Cache Social Media Media Website 92

Brendan Gregg

SEPTEMBER 5, 2017

LTS (April 2016). I wrote about it in a previous post, [DTrace for Linux 2016]. Here's some output from my zfsdist tool, in bcc/BPF, which measures ZFS latency as a histogram on Linux: # zfsdist. Tracing ZFS operation latency. Oracle VM Server is based on Xen. The hardest part on Linux is now done: kernel support.

Virtualization 76

Virtualization AWS Engineering Hardware 76

Rigor

JULY 2, 2019

You can find more information about modifying this file within your server’s documentation. When setting up server-side redirection, be sure to keep the redirect URL consistent with the alternate URL specified in the page’s link rel=”alternate” tag or in the sitemap. Originally published September 2016, updated July 2019.

Mobile 60

Mobile Traffic Google Latency 60

Brendan Gregg

OCTOBER 7, 2018

Screenshot: tracing read latency for PID 181: # bpftrace -e 'kprobe:vfs_read /pid == 30153/ { @start[tid] = nsecs; } kretprobe:vfs_read /@start[tid]/ { @ns = hist(nsecs - @start[tid]); delete(@start[tid]); }'. Back then I could already tell if disks were seeking by interpreting iostat(1) output: seeing high disk latency but small I/O.

C++ 40

C++ Virtualization Programming Latency 40

Alex Russell

OCTOBER 22, 2017

Late-loading JavaScript can cause “server-side rendered” pages to fail in infuriating ways. The server sends it as a stream of bytes and when the browser encounters each of the sub-resources referenced in the document, it requests them. The true median device from 2016 sold at about ~$200 unlocked.

Performance 68

Performance Benchmarking Network Mobile 68

Alex Russell

FEBRUARY 3, 2023

They understood that most websites lack tight latency budgeting, dedicated performance teams, hawkish management reviews, ship gates to prevent regressions, and end-to-end measurements of critical user journeys. "Server-Side Rendering", a.k.a. "SSR" " [ an intro to "isomorphic javascript", a.k.a. "Server-Side

Social Media 119

Social Media Website Technology Technology 119