perf
Hacker ApprovedThe most recommended of 9 profilers
Free Linux profiler that people rely on to find where code spends its time, and to build intuition for CPU performance. Its output is raw, and it expects you to already understand the OS.
Free Linux profiler that people rely on to find where code spends its time, and to build intuition for CPU performance. Its output is raw, and it expects you to already understand the OS.
17 people gave an opinion
- recommend it
- 13
- criticize it
- 4
- approval share
- 76%
Recommended in 8 of 13 months
- November 2025: not recommended
- December 2025: recommended
- January 2026: recommended
- February 2026: recommended
- March 2026: recommended
- April 2026: recommended
- May 2026: not recommended
- June 2026: not recommended
- July 2026: recommended
- August 2026: recommended
- September 2026: recommended
- October 2026: not recommended
- November 2026: not recommended (month in progress)
Why it carries the badge
- 13 people recommend itNeeds 10 or more, met.
- 3.3 recommenders for every criticNeeds 2 to 1 or better, met.
- Recommended in 8 of 13 monthsNeeds 4 or more, met.
The same three rules apply to every product, and the badge can’t be bought. How the badge works
What people say about it
The reasons people give, with the number of comments that give each one. Open a reason to read what they said.
Why people recommend it
Each mark is one comment
Go-to tool for profiling
“You can always go through cachegrind or perf and see what happens with your code.”
Comment from 17 Apr 2026 in “30 Years of HPC: many hardware advances, little adoption of new languages” “that's the best tool for my jobs”
Comment from 24 Aug 2026 in “What Is a Harness?” “You can also just use perf”
Comment from 9 Dec 2025 in “Latency Profiling in Python: From Code Bottlenecks to Observability” Simple to use, gets far
“Perf, instruments and UIForETW are simple enough to use that anyone who can follow the instructions”
Comment from 3 Jan 2026 in “Profiling with Ctrl-C” “perf record + perf report will get you pretty far on Linux”
Comment from 5 Apr 2026 in “Baby's Second Garbage Collector” Builds intuition for CPU performance
“Using perf on Linux has been very educational for me to get an intuition for modern CPU performance.”
Comment from 25 Jul 2026 in “SIMD for Collision” “Getting familiar with linux's perf tool is also helpful”
Comment from 10 Dec 2025 in “Super-Flat ASTs”
What people warn about
Each mark is one comment
Assumes you know the OS
“perf assumes you know how the OS works, and what various syscalls are doing.”
Comment from 8 Feb 2026 in “Why E cores make Apple Silicon fast” “it's not optimized for reality because that knowledge can't be assumed”
Comment from 8 Feb 2026 in “Why E cores make Apple Silicon fast”
Other profilers people recommend
The four most recommended other profilers, with the same counts for each, so you can compare like for like. The tick on each bar marks the 2 to 1 line the badge needs.
| Product | Recommend | Criticize | Approval | Months | Owned | Badge |
|---|---|---|---|---|---|---|
| perfThis page | 13 | 4 | 76% | 8 | — | Approved |
| Java Flight Recorder | 10 | 0 | 100% | 6 | — | Approved |
| Instruments | 9 | 2 | 82% | 5 | — | — |
| Perfetto | 8 | 2 | 80% | 4 | — | — |
| Python 3.15 sampling profiler | 6 | 1 | 86% | 3 | — | — |
What people said
13 of the 18 comments that mention it, newest first. Each links to the original comment.
“I managed to confirm my suspicions with judicious use of perf”
“that's the best tool for my jobs”
“Using perf on Linux has been very educational for me to get an intuition for modern CPU performance.”
“You can always go through cachegrind or perf and see what happens with your code.”
“perf record + perf report will get you pretty far on Linux”
“it's not optimized for reality because that knowledge can't be assumed”
“perf assumes you know how the OS works, and what various syscalls are doing.”
“perf is a raw data dump from the kernel with some lipstick on it”
“It is extraordinarily rare to find command-line tools or other low-level tools that are well designed enough to do this.”
“Perf, instruments and UIForETW are simple enough to use that anyone who can follow the instructions”
“GDB and perf are not even in the same league.”
“Getting familiar with linux's perf tool is also helpful”
“You can also just use perf”
Counts come from 1,795,640 Hacker News comments, November 2025 to November 2026. How we count. Report a mistake.