# Alarm-evt performance difference between windows 10 and ubuntu 23.04

**URL:** <https://racket.discourse.group/t/alarm-evt-performance-difference-between-windows-10-and-ubuntu-23-04/2901>\
**Category:** Questions & Answers\
**Tags:** question\
**Created:** [May 4, 2024, 1:16pm UTC](https://racket.discourse.group/t/alarm-evt-performance-difference-between-windows-10-and-ubuntu-23-04/2901 "2024-05-04T13:16:13Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![uu27183141](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/uu27183141/32/1577_2.png) [@uu27183141](https://racket.discourse.group/u/uu27183141)\
**Post date:** [May 4, 2024, 1:16pm UTC](https://racket.discourse.group/t/alarm-evt-performance-difference-between-windows-10-and-ubuntu-23-04/2901/1 "2024-05-04T13:16:13Z")

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Hi.

I have a question about [alarm-evt](https://docs.racket-lang.org/reference/sync.html#%28def._%28%28quote._~23~25kernel%29._alarm-evt%29%29).

Below is example code.

```scheme
(module b racket
  (define (f)
    (sync/enable-break (handle-evt (alarm-evt (+ (current-inexact-milliseconds)
                                                 (random 500 1000 (current-pseudo-random-generator))))
                                   (lambda (a) (f)))))
  (for ([i 200])
    (thread (lambda () (f)))))

```

With my i7-6700 cpu, when it was on windows 10, cpu load was about 4%, but when it was on ubuntu 23.04, cpu load was about 40%.

Did i do something wrong?

Thanks for reading.

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<div class="post-metadata">

**Author:** ![greghendershott](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/greghendershott/32/98_2.png) [@greghendershott](https://racket.discourse.group/u/greghendershott)\
**Post date:** [May 6, 2024, 4:06pm UTC](https://racket.discourse.group/t/alarm-evt-performance-difference-between-windows-10-and-ubuntu-23-04/2901/2 "2024-05-06T16:06:50Z")

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For me on Debian 12 with an i7-8550u the `racket` process shows around 4%.

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<div class="post-metadata">

**Author:** ![uu27183141](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/uu27183141/32/1577_2.png) [@uu27183141](https://racket.discourse.group/u/uu27183141)\
**Post date:** [May 11, 2024, 1:17pm UTC](https://racket.discourse.group/t/alarm-evt-performance-difference-between-windows-10-and-ubuntu-23-04/2901/3 "2024-05-11T13:17:51Z")

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Hi.

At first, I have to admit that I used a performance measuring means incorrectly.

The utility that I used is [htop](https://htop.dev/) and I thought the column `CPU%` which has column name `PERCENT_CPU` was answer.  
But, actually the answer was the column `NCPU%` which has column name `PERCENT_NORM_CPU` and cpu load was about 4%.

Sorry for bad english writing and thanks for reply.