Brendan Gregg

FEBRUARY 28, 2023

My personal opinion is that I don't see a widespread need for more capacity given horizontal scaling and servers that can already exceed 1 Tbyte of DRAM; bandwidth is also helpful, but I'd be concerned about the increased latency for adding a hop to more memory. Or even on a plane.

Performance 110

Performance Latency Cache Virtualization 110

Brendan Gregg

FEBRUARY 28, 2023

My personal opinion is that I don't see a widespread need for more capacity given horizontal scaling and servers that can already exceed 1 Tbyte of DRAM; bandwidth is also helpful, but I'd be concerned about the increased latency for adding a hop to more memory. Or even on a plane. It was a great privilege.

Performance 52

Performance Latency Cache Virtualization 52

ACM Sigarch

MAY 31, 2023

using Compute Express Link or CXL), organizing memory components for optimal performance, adapting system software traditionally designed for homogeneous memory systems, and developing memory abstractions and programming constructs for HCM management. Figure 2: Latency characteristics of memory technologies (source: Maruf et al.,

Latency 52

Latency Hardware Cache Architecture 52

Brendan Gregg

AUGUST 18, 2019

For example, iostat(1), or a monitoring agent, may tell you your average disk latency, but not the distribution of this latency. For smaller environments, it can be of more use helping eliminate latency outliers. bpftrace uses BPF (Berkeley Packet Filter), an in-kernel execution engine that processes a virtual instruction set.

Latency 68

Latency C++ Cache Programming 68

Brendan Gregg

SEPTEMBER 25, 2021

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. CLI tools The Cassandra systems were EC2 virtual machine (Xen) instances. Was there some other program consuming CPU, like a misbehaving Ubuntu service that wasn't in CentOS? These can be invisible to top(8).

Speed 126

Speed Java AWS Virtualization 126

The Morning Paper

DECEMBER 8, 2019

At the start of November I was privileged to attend HPTS (the High Performance Transaction Systems) conference in Asilomar. On the last morning of the conference Daniel Bittman presented some of the work being done in the context of the Twizzler OS project to explore new programming models for NVM.

Hardware 56

Hardware Programming Media Storage 56

Brendan Gregg

SEPTEMBER 25, 2021

A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. CLI tools The Cassandra systems were EC2 virtual machine (Xen) instances. Was there some other program consuming CPU, like a misbehaving Ubuntu service that wasn't in CentOS? These can be invisible to top(8).

Speed 52

Speed Java AWS Virtualization 52