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 103

Speed Java AWS Virtualization 103

MachMetrics

JUNE 16, 2020

In a vacuum, an SSL certificate does add some additional latency, as it requires 2 extra round trips to establish a secure connection before sending any data to the browser. Secondly, SSL/HTTPS unlocks additional web performance benefits that more than make up for the added latency. To be completely honest, you almost have to use it.

Speed 86

Speed Latency Google Website 86

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

SQL Server According to Bob

SEPTEMBER 26, 2016

When we released Always On Availability Groups in SQL Server 2012 as a new and powerful way to achieve high availability, hardware environments included NUMA machines with low-end multi-core processors and SATA and SAN drives for storage (some SSDs). As we moved towards SQL Server 2014, the pace of hardware accelerated.

Availability 40

Availability Servers Hardware Benchmarking 40

SQL Performance

FEBRUARY 22, 2021

I would like to share a couple of recent examples that help illustrate how using deprecated SQL Server features continues to bite us. The system table sys.sysprocesses was replaced way back in SQL Server 2005 by a set of dynamic management views (DMVs), most notably sys.dm_exec_requests , sys.dm_exec_sessions , and sys.dm_exec_connections.

Latency 57

Latency Servers Monitoring Systems 57

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

JULY 4, 2021

I summarized these topics and more as a plenary conference talk, including my own predictions (as a senior performance engineer) for the future of computing performance, with a focus on back-end servers. Ford, et al., “TCP

Performance 52

Performance Latency Hardware Storage 52

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. mid-priced Androids were slightly faster than 2014's iPhone 6.

Performance 127

Performance Network Metrics Cache 127

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. Render on the server If you’re using a client-side MVC framework, make sure you pre-render on the server. Firefox 31.

Latency 41

Latency Google Hardware Servers 41

Abhishek Tiwari

NOVEMBER 3, 2018

If you put your whole website on CDN, technically you don’t need a large number of server infrastructure and CMS licenses. Using CDN for the whole website, you can offload most of the website traffic to your CDN which will handle not only large traffic spikes but also reduce the latency of content delivery.

Systems 63

Systems Cache Website Network 63

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

SQL Performance

APRIL 8, 2019

These AMD EPYC processors have a number of advantages for SQL Server workloads, as I will explain in this article. This 14nm first-generation AMD EPYC 7551 processor has 32 cores and 64 threads, and it works in one or two-socket servers. This makes it a good choice for many SQL Server workloads, especially DW workloads.

Azure 42

Azure Virtualization Storage Benchmarking 42

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 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 75

Virtualization AWS Engineering Hardware 75

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

Brendan Gregg

JULY 2, 2021

biolatency Disk I/O latency histogram heat map 5. runqlat CPU scheduler latency heat map 10. The architecture is: While the bpftrace binary is installed on all the target systems, the bpftrace tools (text files) live on a web server and are pushed out when needed. execsnoop New processes (via exec(2)) table 2. at the time.

Open Source 40

Open Source Latency Cache Energy 40

CSS Wizardry

MARCH 3, 2019

This includes CDNs, proxy servers, and the like. Once the 60 seconds is up, the browser will head back to the server to revalidate the file. It means ‘do no t serve a copy from cache until you’ve revalidated it with the server and the server said you can use the cached copy’. public and private. Cache-Control: no-cache.

Cache 266

Cache Latency Strategy Servers 266

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 110

AWS Airlines Latency Games 110

KeyCDN

JUNE 20, 2019

Online users are becoming less and less patient meaning you as an eCommerce store owner need to implement methods for reducing latency and speeding up your website. With a CDN, you can offload your static assets such as product images, videos, GIFs, CSS files, and much more to the CDN’s edge servers.

Ecommerce 41

Ecommerce Speed Website Mobile 41