Quick dumb question: CPU Load average: out of 1, or 100?

[moeburn]

Are the 1min/5min/15min CPU load averages a percent value?

IE my WNDR3700v2 says:

CPU Load Averages: 0.17 / 0.09 / 0.06 (1/5/15 minutes)

Does that mean that in the past 1 minute, the CPU load average was 0.17%, or does it mean that it was 17%?

[ericwong]

Read this
http://blog.scoutapp.com/articles/2009/ ... d-averages

or related topic

[moeburn]

Ah. So it's neither. According to the 'top' command in the ssh terminal, about 30% cpu usage (mostly coming from Transmission actively downloading torrents) is equal to a load value of around 1.15. And I'm sure its probably more complicated than that, and doesn't just scale up lineally to higher CPU load values.

But ultimately, what my real question is, is it bad if all my load values (all 1/5/15min averages, that is) are greater than 1.0, at almost all times while I have torrents downloading?

Anecdotally, while Transmission is actively downloading torrents, I haven't noticed any slowdown in internet surfing, Netflix/Youtube streaming, or upload/download performance, mostly because of Gargoyle's awesome QoS.

But I have noticed that the Gargoyle config page seems to load much slower; 2-5 seconds for each page to load, versus less than 2 seconds when Transmission is idle/disabled. SAMBA copies to/from the attached USB drive are also slower, but that is to be expected, seeing as how Transmission is actively writing to the same very old 80GB HDD, as is the SWAP partition.

There's another question. The SWAP partition is on a very old harddrive; is there a chance that if the hard drive is slow enough, having a swap partition on it will actually make some things slower than no swap at all? Right now, only 3.8MB of the 250MB swap partition is used, according to the gargoyle web UI.

Thanks for reading all this, and thanks for your help!

[ericwong]

But ultimately, what my real question is, is it bad if all my load values (all 1/5/15min averages, that is) are greater than 1.0, at almost all times while I have torrents downloading?

Yes, assuming you have a single core cpu, it shouldn't be 1 all the time.
If it is, it is a sign that you need a faster cpu in your router.

But having said that, it could be the fact that you are looking at the gargoyle admin page to check this may also causes the high cpu load. The constant refresh you maybe making could cause massive cpu load. I know this is true for Openwrt if autofresh is on.

seeing as how Transmission is actively writing to the same very old 80GB HDD, as is the SWAP partition.

On my router, read/write to USB drive uses a lot of CPU.
It could be the same reason on your router.

[moeburn]

But ultimately, what my real question is, is it bad if all my load values (all 1/5/15min averages, that is) are greater than 1.0, at almost all times while I have torrents downloading?

Yes, assuming you have a single core cpu, it shouldn't be 1 all the time.
If it is, it is a sign that you need a faster cpu in your router.

But having said that, it could be the fact that you are looking at the gargoyle admin page to check this may also causes the high cpu load. The constant refresh you maybe making could cause massive cpu load. I know this is true for Openwrt if autofresh is on.

seeing as how Transmission is actively writing to the same very old 80GB HDD, as is the SWAP partition.

On my router, read/write to USB drive uses a lot of CPU.
It could be the same reason on your router.

Actually, I tried using the 'top' command to view CPU load, instead of the Gargoyle page, and load was still above 1.0. The only way the 'top' command was intensive enough to even show up on the list, was if I ran it as 'top -D 1', to refresh once every second, and then 'top' was using about 2-3% cpu itself. But it's mostly Transmission, using 30% of the single core 680mhz cpu (WNDR3700v2).

I would have thought a constant 30% CPU usage was "okay" to run a router on. I imagine it's like I just had a cheaper, 300mhz-ish router.

[ericwong]

Actually, I tried using the 'top' command to view CPU load, instead of the Gargoyle page, and load was still above 1.0. The only way the 'top' command was intensive enough to even show up on the list, was if I ran it as 'top -D 1', to refresh once every second, and then 'top' was using about 2-3% cpu itself.

Using top command is fine, it won't stress the cpu as badly as the web ui does.. as you have found.

But it's mostly Transmission, using 30% of the single core 680mhz cpu (WNDR3700v2).

using 30% is fine but what I am saying is the fact cpu usage is 1 most the time, 1 = 100%

But since you are already using a 680Mhz cpu router, I guess there isn't faster router cpu available.

[moeburn]

using 30% is fine but what I am saying is the fact cpu usage is 1 most the time, 1 = 100%

But since you are already using a 680Mhz cpu router, I guess there isn't faster router cpu available.

This is so confusing.... So the Load value and the % usage value aren't proportionally related. I understand that a load value of 1 means that the cpu is currently doing as much work as it can, and that anything higher than 1 means that other operations have to wait.

So in theory, a load value of 1 should mean that the CPU usage is 100%. But it doesn't. Not on this router, anyway. It does on my other linux computer, which has a dual core processor, so that when I see my cpu usage climb to 100%, I also see the load value climb to 2.0.

I've read other forum posts from people saying that the load values in OpenWRT are horribly inaccurate. Perhaps the same is true for Gargoyle? My WNDR3700v2 uses an Atheros AR7161 680mhz cpu, perhaps it is doing hyperthreading to simulate 2 or 4 cores, which means a load value of 4 actually means 100% cpu? That would explain why I always see a load value of around 1.0 when I see around 25% CPU usage.

[ericwong]

I've read other forum posts from people saying that the load values in OpenWRT are horribly inaccurate. Perhaps the same is true for Gargoyle? My WNDR3700v2 uses an Atheros AR7161 680mhz cpu, perhaps it is doing hyperthreading to simulate 2 or 4 cores, which means a load value of 4 actually means 100% cpu? That would explain why I always see a load value of around 1.0 when I see around 25% CPU usage.

I don't know. I am only basing my reply on what linux does.
I don't think any router cpu is capable of hyperthreading or similar.
Maybe someone else who is more knowledgeable in this area might respond to your question.

[Libra]

If you're still interested, you can use the command

Code: Select all

cat /proc/cpuinfo

to get the info about your cpu(s) and core(s).
processor: 0 core: 0 is the first cpu first core, processor: 0 core: 1 is the first cpu second core, etc.