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]); }'. Here's a comparison for an average-sized DTraceToolkit script (seeksize.d) ply is also C, whereas bpftrace is C++. #

C++ 110

C++ Virtualization Programming Latency 110

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. Thankfully, I found some older linux-devel mailing list archives, rescued from server backups, often stored as tarballs of digests. Latency was acceptable and no one complained.

Latency 111

Latency Metrics C++ Systems 111

SQL Server According to Bob

JANUARY 11, 2020

Microsoft, ​​ Windows, ​​ Windows NT, ​​ and Windows Server ​​ are registered trademarks of Microsoft Corporation in the United States and/or other countries. The names of actual companies and products mentioned herein may be the trademarks of their respective owners.

Servers 40

Servers Cache Database Media 40

Brendan Gregg

SEPTEMBER 25, 2021

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. This server is spending about a third of its CPU cycles just checking the time! As (C) looked like a kernel rebuild, I started with (D) and (E). What on Earth is Ubuntu doing that results in 30% higher CPU time!? us on Ubuntu.

Speed 52

Speed Java AWS Virtualization 52

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

Brendan Gregg

SEPTEMBER 25, 2021

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. This server is spending about a third of its CPU cycles just checking the time! As (C) looked like a kernel rebuild, I started with (D) and (E). ## 6. What on Earth is Ubuntu doing that results in 30% higher CPU time!?

Speed 40

Speed Java AWS Virtualization 40

Percona

MAY 2, 2023

During the logical backups, using client API, the data gets read from the server and returned back to the same API, which will be serialized and written into respective “ bson”, “ json” or “ csv” backup files on disk depending upon the type of backup utilities used.

Best Practices 52

Best Practices Database Storage Servers 52

Smashing Magazine

JANUARY 11, 2021

Alternatively, you can also use: Addy Osmani’s Chrome UX Report Compare Tool , Speed Scorecard (also provides a revenue impact estimator), Real User Experience Test Comparison or SiteSpeed CI (based on synthetic testing). It used to provide an insight into how quickly the server outputs any data. What does it mean?

Performance 145

Performance Cache Media Metrics 145

HammerDB

OCTOBER 12, 2018

This post complements the previous best practice guides this time with the focus on MySQL and MariaDB and achieving top levels of performance with the HammerDB MySQL TPC-C test. SELECT DISTINCT c from sbtest where id between ? order by c. SELECT c from sbtest where id=? Copyright (C) 2003-2018 Steve Shaw.

Best Practices 40

Best Practices Scalability Performance C++ 40

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]); }'. Here's a comparison for an average-sized DTraceToolkit script (seeksize.d) ply is also C, whereas bpftrace is C++. #

C++ 40

C++ Virtualization Programming Latency 40

Smashing Magazine

JANUARY 6, 2020

Is it worth exploring tree-shaking, scope hoisting, code-splitting, and all the fancy loading patterns with intersection observer, server push, clients hints, HTTP/2, service workers and — oh my — edge workers? It used to provide an insight into how quickly the server outputs any data. Large preview ). What does it mean?

Performance 145

Performance Cache Network Metrics 145

Smashing Magazine

JANUARY 7, 2019

Is it worth exploring tree-shaking, scope hoisting, code-splitting, and all the fancy loading patterns with intersection observer, server push, clients hints, HTTP/2, service workers and — oh my — edge workers? Long FMP usually indicates JavaScript blocking the main thread, but could be related to back-end/server issues as well.

Performance 104

Performance Cache Metrics Network 104

Brendan Gregg

SEPTEMBER 5, 2017

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. Hit Ctrl-C to end. ^C C operation = 'read' usecs : count distribution 0 -> 1 : 0 | | 2 -> 3 : 0 | | 4 -> 7 : 4479 | *| 8 -> 15 : 1028 | | 16 -> 31 : 14 | | 32 -> 63 : 1 | | [.].

Virtualization 76

Virtualization AWS Engineering Hardware 76

The Netflix TechBlog

MARCH 13, 2020

Compared to the most recent master version of libaom (AV1 reference software), SVT-AV1 is similar in compression efficiency and at the same time achieves significantly lower encoding latency on multi-core platforms when using its inherent parallelization capabilities.

Open Source 154

Open Source Efficiency C++ Speed 154

Smashing Magazine

AUGUST 22, 2021

Because we are dealing with network protocols here, we will mainly look at network aspects, of which two are most important: latency and bandwidth. Latency can be roughly defined as the time it takes to send a packet from point A (say, the client) to point B (the server). Two-way latency is often called round-trip time (RTT).

Performance 107

Performance Network Latency Servers 107

Smashing Magazine

AUGUST 9, 2021

You’ve probably heard things like: “HTTP/3 is much faster than HTTP/2 when there is packet loss”, or “HTTP/3 connections have less latency and take less time to set up”, and probably “HTTP/3 can send data more quickly and can send more resources in parallel”. HTTP/2 versus HTTP/3 protocol stack comparison ( Large preview ).

Transportation 145

Transportation Internet Internet Network 145

Smashing Magazine

SEPTEMBER 6, 2021

Next, we’ll look at how to set up servers and clients (that’s the hard part unless you’re using a content delivery network (CDN)). This difference by itself doesn’t do all that much (it mainly reduces the overhead on the server-side), but it leads to most of the following points. Server Sharding and Connection Coalescing.

Network 107

Network Servers Cache Traffic 107