kafi.dev

Systems engineer · London

Ahmed Kafi

Low-latency Java, the JVM, and trading systems infrastructure.

Systems engineer, London. I work on low-latency, event-driven trading systems in Java.

I write here about what happens beneath the code: JVM internals, allocation-free technique, Aeron and the Real Logic stack, binary encodings, and how to measure any of it without fooling yourself.

Read the writing prokafiahmed@gmail.com

Threads stopping at their poll points for a safepointThree threads run left to right along a time axis. A vertical mark shows where a VM operation is requested. Each thread continues to its next poll point and stops, at a different time. The shaded region between the request and the last thread stopping is the time to safepoint.
time to safepoint time → The pause that is not in your GC log.

Writing

1 published

  1. 01 Stack vs heap: what actually lives where The two regions every running program uses, what Java actually puts in each, and the places the usual explanation quietly gets it wrong. JDK 21

Work

Experience across the world of Computing

Systems Engineer / Consultant
Adaptive Financial, London Low-latency, event-driven trading systems in Java. Aeron, Agrona, SBE, and the measurement discipline needed to know whether a change actually helped.
2024-current
Software Developer
Ofcom, London App safety and protection team. Machine learning and computer vision projects.
2023
BSc Computer Science
King's College London
2021-2024

No stack list, and no certifications. Whatever ends up worth showing will be in the source.