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 126

Speed Java AWS Virtualization 126

SQL Performance

JUNE 21, 2019

I wrote a blog about it years ago too, however as time has marched on, guidance has changed a bit. Jonathan Kehayias has written an blog post How much memory does my SQL Server actually need , with a formula that helps establish the baseline for the maximum memory value. For many years I've found users making the same mistakes.

Servers 49

Servers Azure Hardware Database 49

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

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). There's a lot about Linux containers that isn't well documented yet, especially since it's a moving target.

Virtualization 76

Virtualization AWS Engineering Hardware 76

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). This can make it difficult to draw sound performance-tuning conclusions.

Servers 95

Servers Tuning Architecture Processing 95