IO River

NOVEMBER 2, 2023

Latency is a concept that increases with distance, so a signal that has to travel 1,000 KM will be much faster compared to a signal sprinting for that 100,000 KM. Maintenance Without MayhemWhat happens when one of your servers/data centers needs a tune-up? Do you just give up the traffic trying to access it while you work on it?

Traffic 52

Traffic Cache Servers Latency 52

IO River

NOVEMBER 2, 2023

Latency is a concept that increases with distance, so a signal that has to travel 1,000 KM will be much faster compared to a signal sprinting for that 100,000 KM. Maintenance Without MayhemWhat happens when one of your servers/data centers needs a tune-up? Do you just give up the traffic trying to access it while you work on it?

Traffic 40

Traffic Cache Network Servers 40

O'Reilly

JANUARY 16, 2024

Unpredictable wait times : Wait times (latency) for ChatGPT’s responses are unpredictable, and there aren’t audio cues to help me establish an expectation for how long I need to wait before it responds. would do if I were on a noisy phone connection with someone and didn’t hear them clearly. Thank you very much for reading.

Entertainment 73

Entertainment Internet Internet Design 73

Brendan Gregg

OCTOBER 8, 2018

Screenshot: tracing read latency for PID 181: # bpftrace -e 'kprobe:vfs_read /pid == 30153/ { @start[tid] = nsecs; } kretprobe:vfs_read /@start[tid]/ { @ns = hist(nsecs - @start[tid]); delete(@start[tid]); }'. Back then I could already tell if disks were seeking by interpreting iostat(1) output: seeing high disk latency but small I/O.

C++ 110

C++ Virtualization Programming Latency 110

Brendan Gregg

OCTOBER 7, 2018

Screenshot: tracing read latency for PID 181: # bpftrace -e 'kprobe:vfs_read /pid == 30153/ { @start[tid] = nsecs; } kretprobe:vfs_read /@start[tid]/ { @ns = hist(nsecs - @start[tid]); delete(@start[tid]); }'. Back then I could already tell if disks were seeking by interpreting iostat(1) output: seeing high disk latency but small I/O.

C++ 40

C++ Virtualization Programming Latency 40

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. Both Xen and KVM have had many performance and security improvements, and workloads can now be tuned to run at almost bare metal speeds (say, a 3% loss or less). Hit Ctrl-C to end. ^C

Virtualization 76

Virtualization AWS Engineering Hardware 76