# VOXL CPU Performance with ROS

Source: https://forum.modalai.com/topic/640/voxl-cpu-performance-with-ros
Category: Flight Core and Legacy VOXL (https://forum.modalai.com/category/9/flight-core-and-legacy-voxl)
Tags: voxl
Posted: 2022-01-09 09:46:46 UTC by Nirge
Replies: 2 · Views: 747

## Nirge · 2022-01-09 09:46:46 UTC

Hi,
I'm migrating an app to VOXL, and noticed the performance is better, but the hidden "sys" values are negating any advantage (28% when 21% is for system).

```
Mem: 2737440K used, 1123880K free, 41796K shrd, 140144K buff, 1824000K cached
CPU:  6.9% usr 20.9% sys  0.0% nic 67.4% idle  0.0% io  2.3% irq  2.3% sirq
Load average: 3.84 3.14 1.65 4/750 13545
```

Using dmesg it seems it's overflowing with errors:
```
[  586.199252] type=1123 audit(1641721335.544:9489): pid=15875 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0-s15:c0.c1023 msg='cwd="/root/.ros" cmd=69776C69737420776C616E30207363616E terminal=? res=failed'
[  586.229739] type=1123 audit(1641721335.574:9490): pid=15876 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0-s15:c0.c1023 msg='cwd="/root/.ros" cmd=69776C69737420776C616E30207363616E terminal=? res=failed'
[  586.269861] type=1123 audit(1641721335.614:9491): pid=15877 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0-s15:c0.c1023 msg='cwd="/root/.ros" cmd=69776C69737420776C616E30207363616E terminal=? res=failed'
[  586.304811] type=1123 audit(1641721335.644:9492): pid=15878 uid=0 auid=4294967295 ses=4294967295 subj=system_u:system_r:init_t:s0-s15:c0.c1023 msg='cwd="/root/.ros" cmd=69776C69737420776C616E30207363616E terminal=? res=failed'
[  586.505185] audit: audit_lost=900 audit_rate_limit=20 audit_backlog_limit=64
[  586.505199] audit: rate limit exceeded
```

Any suggestions on how to diagnose this issue?

## Reply by Chad Sweet (ModalAI staff) · 2022-01-09 16:51:44 UTC

If you are just using top, it may not be the complete story. The Snapdragon 821 CPU scales the frequencies based on usage, but top does not take that into account.

The [voxl-inspect-cpu](https://docs.modalai.com/voxl-inspect-cpu/) tool does take that into account

The thermal and performance [page](https://docs.modalai.com/thermal-and-performance/) may also be interesting

## Reply by Nirge · 2022-01-12 13:05:39 UTC (in reply to Chad Sweet)

@Chad-Sweet Hi, the utility shows the same CPU usage if I add usr & sys.