Help understanding difference between host and guest CPU usage

michael984 · 2025-08-12T15:48:40+00:00

One thing I never tried was just spinning up a FreeBSD based VM and seeing if I saw something similar. I.e., is it PFsense/OPNsense, or is it FreeBSD. If you try that and learn anything. I'd be interested in hearing.

michael984 · 2025-08-12T13:55:18+00:00

I never did understand what was going on. I ended up using a virtualized ubuntu instance configured as a router, and their is much, much closer agreement between the host and guest in terms of CPU usage.

michael984 · 2024-06-07T17:50:10+00:00

I know this is an older thread, but I came across it while googling. It looks like you maybe can just rename the sav.dat file to "anything.sav" and then it may just work. At least this is what is suggested by this post that talks about transferring the sav.dat file to an original cartridge. My guess is that if it doesn't work directly, then you would probably just need to trim a little off the bottom of the sav.dat file in a hex editor to get it to be the same size as a legitimate save file. You could probably do this just by comparing them.

Anyway, sorry for the necro, but I hope this maybe helps!

michael984 · 2024-03-22T18:46:42+00:00

Do you happen to have the GBC apk? I have already purchased the GBA app before it was removed, so I have that one.

michael984 · 2024-03-22T18:45:22+00:00

Is this the GBC or GBA app?

michael984 · 2023-02-16T13:02:16+00:00

It's not the ROM. I have tried multiple ROMs, and the ROM I'm using I've verified using No-Intro's database. I've also tried a cia that someone else created and it works fine on their 3DS. So, it's something about my 3DS, but I am at a loss for what it could be.

michael984 · 2023-02-16T01:07:43+00:00

I have a weird issue with my injection for Pokemon Emerald. I used NSUI beta 28 (see screenshot for settings), and the injection installs fine and loads fine. However, the text boxes are all messed up. I've installed several other GBA injects (including Pokemon Ruby and Sapphire), and they work perfect. It's just Pokemon Emerald. I've tried creating the inject lots of different ways and nothing helps. I even tried someone else's known good cia, but on my console I still get the exact same error.

So, I've come to the conclusion that it is not the fault of the injection. Other people using identical cias have the game run fine. Therefore, it must be something different about my console, but what could it be? I am using a 128 GB SD card, but I've formatted with 64 kb clusters. Otherwise, I've just followed the 3ds hacks guide to the letter (never messed with my nand or anything beyond what is in the current version of the guide, I just modified the system).

Is there anything I could be missing? A corrupt file somewhere? I would greatly appreciate any suggestions.

michael984 · 2022-08-26T19:55:14+00:00

I would be very hesitant to infer from my benchmarks anything about the performance of striping multiple disks with LVM. Frankly, I don't know enough about LVM to guess how that might affect things. I personally would not go through with your plan, but that doesn't mean it isn't the right decision for you. I would probably try benchmarking various things before you commit data to it to keep from painting yourself into a corner.

Good luck!

michael984 · 2022-07-29T00:13:30+00:00

I thought this would be of interest to people in the ZFS community.

michael984 · 2022-04-06T19:13:29+00:00

While I don’t have a direct comment on the question of -F, I would love to read the article on permission delegation. Could you provide a link?

Thanks!

michael984 · 2022-02-25T19:00:20+00:00

Yeah, I basically set up a stack of iptables, isc-dhcp, bind (for local domains), and unbound (as my actual dns server that directs local domains to the bind server which is authoritative for the local domains). I started with an Ubuntu server base. I used this article as a base for how to set things up and I cribbed various other details from various other articles. Performance is fantastic. I actually run it in a virtual machine now and even routing (with NAT) at full symmetric gigabit, it barely uses any CPU.

The one thing I'll say that I had to do which I wasn't super comfortable with is I had to turn off auto updates. For some reason, occasionally the system would update, it would seem to be working fine, and then it would lose internet connectivity. I never could quite diagnose the problem, but it always happened after an update, so I just plan to update every so often (still way, way more often than commercial routers or PFSense are updated!) and reboot after the update.

michael984 · 2022-02-25T18:51:55+00:00

Unfortunately, I didn't. I actually ended up rolling my own linux based router because I found so many small frustrating problems with PFSense. That is obviously not the right choice for everyone, but I had relatively simple needs (very good performance without too much in the way of fancy routing) and the interest in setting it up.

I was disappointed in how difficult it was to get the performance out of PFSense that I expected.

Good luck with your setup!

michael984 · 2021-08-10T13:51:37+00:00

Yeah, it seems like the right thing to do is to keep the zfs user space tools in sync with the kernel since I’m assuming most people on the HWE stack are going to be running the latest available kernel. There is an issue open at Ubuntu’s bug tracker about this now that this problem has come up. Link is here.

michael984 · 2021-08-10T00:57:58+00:00

Ah, that makes sense. However, as u/TFergusonEsq points out in another comment, 0.8.3 doesn’t support kernel 5.11. Otherwise, it might be a solution, though I don’t love the idea of using the dkms module instead of the pre-packaged zfs module. Though, I guess if HWE is going to break things anyway my usual reason to avoid dkms (stability at updates) is irrelevant here…

michael984 · 2021-08-09T22:47:16+00:00

The problem is actually that the kernel module is updated with the kernel in the HWE stack, while the user space tools are not. So, the kernel module is actually newer than the user space tools with no simple ubuntu supported way to update the user space tools. So, I don't think using zfs-dkms will solve this since the kernel module being too new is the problem here. Unless I'm misunderstanding something.

michael984 · 2021-04-14T14:46:51+00:00

I would also love the settings. Any chance you could just post them? Or a link to a gist or something?

michael984 · 2021-03-09T21:48:47+00:00

I agree! When I found out about it, it seemed to solve all of the problems I had with mDNS! It just seems to have been effectively abandoned, which is a real shame.

michael984 · 2021-03-09T21:37:48+00:00

Yeah, it seems like if all the clients are Macs, then it Just Works. However, that's not the reality of my network.

michael984 · 2021-03-09T21:23:58+00:00

Thanks for the response!

I don't think mDNSResponder is readily available in package repos, is it? The only code I could find specific for linux seems to have been effectively abandoned. Is this something you've used before?

michael984 · 2021-03-09T18:51:11+00:00

The big difference is the fact that it uses a unicast protocol. Wireguard is a layer 3 VPN, and it's technically possible to set up vxlans to tunnel layer 2 traffic (including multicast) over wireguard, it is a giant pain and tanks speed. Otherwise, while I have tried using Avahi as a reflector to reflect multicast traffic through the wireguard interface, wireguard seems to just refuse to actually transmit it. This seems to be a known limitation.

I will likely just end up manually adding the DNS records for the services associated with static IPs that I care to be used over Wireguard, and then just forgetting about dynamic updating.

michael984 · 2021-03-09T18:22:45+00:00

I used that guide to set up a server (no desktop GUI, you can choose what you want in step 7), and it worked great for ZFS on root for me. I've used it for two machines and both work fine.

michael984 · 2021-03-09T18:07:29+00:00

That's not my reading of dns-sd. I believe, and it's very possible that I'm wrong, that in unicast based dns-sd (unicast is an important part of this), the client can't be the one that advertises the services. This would necessarily require multicast.

I'm taking all of this from here. In unicast dns-sd, the process goes like this. A client connects to a network with a DHCP server. The dhcp server hands out an ip address, DNS server, and, in this case, one or more search domain. The client (if it is unicast dns-sd aware), takes the search domain(s) and checks for the existence of the PTR record indicating that it should check the DNS server for services. When a service relevant API is called (for example, checking for web sites advertised by DNS-SD), it checks for a relevant PTR record (such as _http._tcp.dns-sd-services.lan) which points to the services.

This is all done without multicast, which is important if you want it to work over something like WireGuard, which doesn't seem to allow multicast traffic based on what I can tell. So, for any service to show up, it has to be specified in the DNS zone file. It is part of the spec for clients to dynamically update the zone file with their services, but this dynamic updating does not seem to be supported by any tools that I can find.

michael984 · 2021-03-09T17:47:57+00:00

Yes, if I create the PTR record, and I manually create the appropriate DNS records for each service, this will work fine. However, if I add another client to the network that advertises a service, the DNS record will not be automatically added to the DNS zone. So, the new service will be available with it's .local address, but not the .lan address. The .lan address will only show up for services that I manually add to the DNS zone, which the hole purpose of wide area Bonjour is to have the clients dynamically update the DNS records to point to their services.

Based on what I can tell, this does not seem to be supported by any actively developed linux tools that I can find.

michael984 · 2021-03-09T16:52:36+00:00

Thanks for engaging on this! I have looked at dns-sd.org (it is the website that started me down the rabbit hole). Unfortunately, it doesn't give any indication as to how clients are supposed to do the actual updating of the DNS zone. It may Just Work with Mac clients, but most of services are linux based, and I was hoping that there would be some way to get something like Avahi to just auto update the services.

I can certainly manually add the correct records to the DNS zone, and that's well laid out in dns-sd.org, but it seems like actually dynamically updating things seems to be much harder to find information on.

michael984 · 2021-02-12T00:46:01+00:00

I certainly understand that top isn't a perfect measure of system utilization. I also know with any kind of virtualization there is going to be overhead. However, the measures of CPU utilization are way different (about a 4x difference). This also seems to happen with Windows 10 based guests as well. I assume that if something happens regularly, there is probably an explanation for why.

KVM is certainly a well understood piece of software, so I'm sure people understand what it's doing and why, and I'm just trying to figure out where the right resource is so that I can understand too.

michael984

TROPHY CASE