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 126

Speed Java AWS Virtualization 126

ACM Sigarch

MARCH 18, 2019

Computer systems, from the Internet-of-Things devices to datacenters, are complex and optimizing them can enhance capability and save money. Developing simulators, however, is time-consuming and requires a great deal of infrastructure development regarding a prospective system. Answered in Part 2.). Bottleneck Analysis.

Systems 60

Systems Latency Performance Analytics 60

ACM Sigarch

MARCH 25, 2019

How many buffers are needed to track pending requests as a function of needed bandwidth and expected latency? Can one both minimize latency and maximize throughput for unscheduled work? The M/M/1 queue will show us a required trade-off among (a) allowing unscheduled task arrivals, (b) minimizing latency, and (c) maximizing throughput.

Systems 53

Systems Latency Performance C++ 53

Brendan Gregg

AUGUST 29, 2021

1072-aws (xxx) 12/18/2018 _x86_64_ (16 CPU) avg-cpu: %user %nice %system %iowait %steal %idle 5.03 avg-cpu: %user %nice %system %iowait %steal %idle 14.81 avg-cpu: %user %nice %system %iowait %steal %idle 14.86 avg-cpu: %user %nice %system %iowait %steal %idle 14.95 avg-cpu: %user %nice %system %iowait %steal %idle 14.54

Cache 105

Cache C++ AWS Latency 105

Brendan Gregg

JULY 2, 2021

This is also applicable for people adding it to their own in-house monitoring systems. You likely already have agents running on all your customer systems. There are so many options it's really your own preference based on your existing system and customer environments. biolatency Disk I/O latency histogram heat map.

Latency 145

Latency Cache Energy Systems 145

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