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. As a Xen guest, this profile was gathered using perf(1) and the kernel's software cpu-clock soft interrupts, not the hardware NMI.

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. As a Xen guest, this profile was gathered using perf(1) and the kernel's software cpu-clock soft interrupts, not the hardware NMI.

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. How bad is it?

Performance 127

Performance Network Metrics Cache 127

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

Smashing Magazine

OCTOBER 27, 2021

Nowadays, hardware and software are designed to conduct eye-tracking studies for marketing , UX , psychological and medical research , gaming , and several other use cases. However, the price of eye-tracking used to be much higher than heatmaps, as measuring users’ gaze required special hardware to be used in-lab.

Mobile 115

Mobile Website Hardware Social Media 115

Brendan Gregg

JULY 4, 2021

This was a chance to talk about other things I've been working on, such as the present and future of hardware performance. The video is on [youtube]: The slides are [here] or as a [PDF]: first prev next last / permalink/zoom I work on many areas of performance, but recently I've had a lot of demand to talk about BPF. Ford, et al., “TCP

Performance 52

Performance Latency Hardware Storage 52

Brendan Gregg

NOVEMBER 28, 2017

Hardware virtualization for cloud computing has come a long way, improving performance using technologies such as VT-x, SR-IOV, VT-d, NVMe, and APICv. The latest AWS hypervisor, Nitro, uses everything to provide a new hardware-assisted hypervisor that is easy to use and has near bare-metal performance. I'd expect between 0.1%

Virtualization 40

Virtualization AWS Hardware Storage 40

SQL Performance

MARCH 17, 2020

Back in 2014, I wrote an article called Performance Tuning the Whole Query Plan. This machine has four i7 CPUs (hyperthreaded to 8) with a base speed of 2.4GHz. The parallel column store aggregate push down result of 57 million rows processed in 7ms (using 40ms of CPU) is remarkable, especially considering the hardware.

Servers 86

Servers Tuning Database Efficiency 86

SQL Performance

JULY 16, 2019

A close monitoring of the hardware enthusiast community, including many of the most respected hardware analysts and reviewers paints an even more dire picture about Intel in the server processor space. This made it easier for database professionals to make the case for a hardware upgrade, and made the typical upgrade more worthwhile.

Servers 46

Servers Hardware Architecture Retail 46

Brendan Gregg

FEBRUARY 28, 2023

References I've reproduced the references from my SREcon22 keynote below, so you can click on links: [Gregg 08] Brendan Gregg, “ZFS L2ARC,” [link] , Jul 2008 [Gregg 10] Brendan Gregg, “Visualizations for Performance Analysis (and More),” [link] , 2010 [Greenberg 11] Marc Greenberg, “DDR4: Double the speed, double the latency?

Performance 52

Performance Latency Cache Virtualization 52

SQL Performance

JUNE 21, 2019

For SQL Server 2008R – 2014, you could lower this threshold using trace flag 2371. While hardware such as intelligent SANs, Solid State Disk, and other advancements have helped speed things up, wasted space in index can translate to wasted space in the buffer pool as well as wasting more I/O.

Servers 49

Servers Azure Hardware Database 49

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) */. Anyway, the following patch seems to make the load average much more consistent WRT the subjective speed of the system.

Latency 111

Latency Metrics C++ Systems 111

Brendan Gregg

SEPTEMBER 5, 2017

Linux has been adding tracing technologies over the years: kprobes (kernel dynamic tracing), uprobes (user-level dynamic tracing), tracepoints (static tracing), and perf_events (profiling and hardware counters). Outside of EC2, many other providers are deploying on KVM. Or, from a different point of view, Solaris was less secure.)

Virtualization 75

Virtualization AWS Engineering Hardware 75

SQL Performance

MARCH 8, 2021

SQL Server 2014 SP2 and later produce runtime (“actual”) execution plans that can include elapsed time and CPU usage for each execution plan operator (see KB3170113 and this blog post by Pedro Lopes). Interpreting these numbers is not always as straightforward as one might expect. The clock keeps running at the same rate even during sleep.

Servers 95

Servers Tuning Architecture Performance 95