John McCalpin

AUGUST 1, 2018

According to Dr. Bandwidth, performance analysis has two recurring themes: How fast should this code (or “simple” variations on this code) run on this hardware? The user environment defines the mapping of MPI ranks to hardware resources (cores, sockets, nodes). The MPI runtime library. in ways that are seldom transparent.

Hardware 40

Hardware Transportation Performance Latency 40

Alex Russell

OCTOBER 22, 2017

We constrain ourselves to a real-world baseline device + network configuration to measure progress. Budgets are scaled to a benchmark network & device. Tools and CI systems help them monitor progress & prevent regressions. The median user is on a slow network. Global Ground-Truth. Where to start?

Performance 68

Performance Benchmarking Network Mobile 68

Sutter's Mill

JUNE 21, 2012

Now welcome to the hardware jungle. First, I don’t agree with the assertion that reliability alone is what’s important, or that it’s more important than latency, for the following reason: You can build reliable transports on top of unreliable ones. We can and do build secure reliable global banking systems on that.

Latency 40

Latency Transportation Hardware Education 40

Smashing Magazine

JANUARY 11, 2021

Networking, HTTP/2, HTTP/3 OCSP stapling, EV/DV certificates, packaging, IPv6, QUIC, HTTP/3. If you don’t have a device at hand, emulate mobile experience on desktop by testing on a throttled 3G network (e.g. Moto G4) on a slow 3G network, emulated at 400ms RTT and 400kbps transfer speed. 300ms RTT, 1.6 Mbps down, 0.8

Performance 145

Performance Cache Media Metrics 145

Smashing Magazine

JANUARY 6, 2020

If you don’t have a device at hand, emulate mobile experience on desktop by testing on a throttled 3G network (e.g. To make the performance impact more visible, you could even introduce 2G Tuesdays or set up a throttled 3G/4G network in your office for faster testing. 300ms RTT, 1.6 Mbps down, 0.8

Performance 145

Performance Cache Network Metrics 145

Smashing Magazine

JANUARY 7, 2019

If you don’t have a device at hand, emulate mobile experience on desktop by testing on a throttled network (e.g. To make the performance impact more visible, you could even introduce 2G Tuesdays or set up a throttled 3G network in your office for faster testing. 150ms RTT, 1.5 Mbps down, 0.7 Mbps up) with a throttled CPU (5× slowdown).

Performance 103

Performance Cache Metrics Network 103

All Things Distributed

APRIL 4, 2017

As well as AWS Regions, we also have 24 AWS Edge Network Locations in Europe. After finding it cost prohibitive to use colocation centers in local markets where their users are based, iZettle decided to give up hardware. AWS is helping them reach their goal of becoming the leader in sustainable transport.

AWS 116

AWS Airlines Latency Games 116

Smashing Magazine

AUGUST 22, 2021

As we will see, QUIC and HTTP/3 indeed have great web performance potential, but mainly for users on slow networks. If your average visitor is on a fast cabled or cellular network, they probably won’t benefit from the new protocols all that much. An often used metaphor is that of a pipe used to transport water. Did You Know?

Performance 105

Performance Network Latency Servers 105