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. Ford, et al., “TCP

Performance 52

Performance Latency Cache Virtualization 52

Brendan Gregg

SEPTEMBER 25, 2021

These strange questions came to the fore back in 2014 when Netflix was switching services from CentOS Linux to Ubuntu, and I helped debug several weird performance issues including one I'll describe here. A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. How would you time time?

Speed 52

Speed Java AWS Virtualization 52

Brendan Gregg

SEPTEMBER 25, 2021

These strange questions came to the fore back in 2014 when Netflix was switching services from CentOS Linux to Ubuntu, and I helped debug several weird performance issues including one I'll describe here. A Cassandra database cluster had switched to Ubuntu and noticed write latency increased by over 30%. How would you _time_ time?

Speed 40

Speed Java AWS Virtualization 40

Alex Russell

MARCH 6, 2021

Devices and networks have evolved too: Alex Russell @slightlylate An update on mobile CPUs and the Performance Inequality Gap: Mid-tier Android devices (~$300) now get the single-core performance of a 2014 iPhone and the multi-core perf of a 2015 iPhone. Hardware Past As Performance Prologue. Mind The Gap.

Performance 124

Performance Network Cache Metrics 124

Tim Kadlec

SEPTEMBER 25, 2014

Macbook Air (2014). Macbook Air (2014). Macbook Air (2014). Macbook Air (2014). On powerful devices, like my Macbook Air (2014), parse and execution time was negligible. Another interesting note was how significant the impact of hardware has on the timing. The result was a 10x reduction in startup latency.

Latency 41

Latency Google Hardware Servers 41

Brendan Gregg

AUGUST 8, 2017

And here's an excerpt from [Linux] today (include/linux/sched/loadavg.h): #define EXP_1 1884 /* 1/exp(5sec/1min) as fixed-point */ #define EXP_5 2014 /* 1/exp(5sec/5min) */ #define EXP_15 2037 /* 1/exp(5sec/15min) */. It's time in some cgroup paths, but this server is not doing much disk I/O. My search was starting to feel cursed.

Latency 111

Latency Metrics C++ Systems 111

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. Oracle VM Server is based on Xen. Many new tools can now be written, and the main toolkit we're working on is [bcc]. Hit Ctrl-C to end. ^C amazon").

Virtualization 76

Virtualization AWS Engineering Hardware 76

All Things Distributed

APRIL 4, 2017

This enables customers to serve content to their end users with low latency, giving them the best application experience. In 2011, AWS opened a Point of Presence (PoP) in Stockholm to enable customers to serve content to their end users with low latency. In 2014 and 2015 respectively, AWS opened offices in Stockholm and Espoo, Finland.

AWS 116

AWS Airlines Latency Games 116