IRQ CPU Affinity Setting

[Nick]

So IntFiltr install glitches are not likely to be service pack related I guess.

Peter,
Thankfully I’m running nothing on SSD at the moment so I hope power cuts will just remain a simple annoyance not a data nightmare (I feel your pain).

Regarding sound changes, I wonder if your DAC electronics being so optimised means  that the OS changes do not make the same level of difference. If your electronics are well clocked and locked on the stream it might be your system has better tolerance to OS induced jitter and timing errors. Just thinking out loud.

Mani,

After reading Peters earlier XX internal settings, I thought I would try special mode again (At last I have understood how to set buffers size and latency for special mode correctly). What I found was I could get 95%+ of the organic quality of Adaptive mode with much better resolution and rightness of tone. Even more like vinyl.

On the HiFace I set the XX buffer size to 2048 but found that the lowest Q1 latency was definatly not where the sweet spot is;

Set Q1 to get 2 sample latency and played with SFS arround 70 - 90 = Much too thin souding and  hyperdetailed

at 4 samples latency and SFS between 70 and 90 = better but nowhere near right

8 samples approaching adaptive mode sound only losing a tiny amount of resolution (or it might be that the forwardness of the lower latency settings is dropping out of the sound)

16 samples hit the sweet spot ! – organic, detailed, smooth and engaging. The surprising thing was just how sensitive getting the sound right was to SFS setting. I had to spend a lot of time on SFS at each latency to get the best sound. In the end I was making changes of 1 and 2 Mb and getting subtle but very important changes in the sound. The end result is all the Adaptive quality but with the resolving power and wonderful presence of Special Mode.

I know you are a fan of Adaptive Mode but it may be that the OS changes enable Special Mode to do this.
Nick.

[PeterSt]

Hi Nick - Thanks.

On the Special Mode : I certainly think the OS (Vista) allows for this now. A bit difficult to judge for me, because the processor (spread !) power is different for me at the same time, although net that power (of one core) should be less compared to what I had.

Regarding sound changes, I wonder if your DAC electronics being so optimised means  that the OS changes do not make the same level of difference. If your electronics are well clocked and locked on the stream it might be your system has better tolerance to OS induced jitter and timing errors. Just thinking out loud.

Nah, don't think so;
It is more important (for me, or for you to get my "message") that I changed too many things within a too small period of time to really judge it to its merits. So, I'm not saying I don't hear the difference, all I'm saying is that I can't dedicate it to those "timing" tweaks. I just don't know !
BUT, as I said, it looks like I'm completely satisfied.

But also, like Flecko just pointed out in the other topic (With RAMDisk and Special Mode: Scheme 3 or Scheme 2 ?): change the Appointment Scheme and you again will know there's more to do (or again more to it).
Too many variables. haha.

Peter

[manisandher]

I know you are a fan of Adaptive Mode but it may be that the OS changes enable Special Mode to do this.

The issue I have with Special mode is that I can't use low buffer sizes - pretty much the whole point of using Special. You see, I've recently switched to using a Weiss AFI1 interface, which uses a firewire connection. I can't use it below 256 samples with Special and Quad Arc Prediction. (Even if I switched QAP off, I doubt I'd get down to 64 samples.) Certainly, my preference is Adaptive over Special-at-256-samples. In this respect, my RME card is much better - perhaps I should give it a go with Special mode...

Mani.

[manisandher]

Too many variables. haha.

I think this happened when you first introduced Q1... haha.

I don't want to sound like a broken record (pun intended), but this is why I've adopted my system of comparing the sound of playback to that of vinyl. But not in a haphazard way, rather a more systematic way. The method requires a good analogue source (I would love a top-end open-reel machine, but use instead a reasonably good turntable) and also a good ADC/DAC (fortunately, I have one of the best ever made).

So, here are the steps:
1. make a digital recording from a good LP (preferably 45rpm) - I usually make three different recordings at 16/44.1, 24/88.2 and 24/176.4
2. listen to the vinyl being played back through the ADC/DAC, set to one of the recording resolutions, say, 16/44.1
3. listen to the same resolution recording, in this case 16/44.1, being played back through XX
4. adjust parameters in XX until the playback sounds as close to vinyl as possible

It sounds like I'm doing AB comparisons, but I'm not (actually, switching between DAC and ADC modes on the Model Two takes a few seconds). In any event, I tend to play a whole track one way and then listen to it again the other way.

Now, I concede that this is not a totally scientific way of doing things (e.g. is the vinyl source good enough?, is the recording software good enough?, is the rest of my system up to resolving any minor nuances?, etc) BUT...

... I would have gone mad changing all the XX parameters ad infinitum were it not for this method. My method lets me know where I am now and how far I still have to go.

Mani.

[PeterSt]

Hmm ... Back on Adaptive Mode here ...
I won't change my sig yet, but there's too much that still sounds "stressy" here, and I can't miss the bass ...

[Marcin_gps]

Hi guys,

Finally I tried this tweak on my machine and I'm not sure if like it. I get more details and clarity but I got a feeling that the sound is somehow sharp/bright. I have to listen more and maybe fine-tune Nick's recommended settings.

Thanks a lot for your effort Nick!

Cheers
Marcin

-EDIT

I hope that Peter's announcement about fixing the SFS is going to do the trick, because I like the increased level of details, deeper soundstage, but I miss the body and punch. Now I can listen at about 20% louder levels whitout any sense of fatigue, which is a good thing  (I guess).


-EDIT2

Nick, so what's your present XXHE settings (Q1, buffer size and SFS)?

[Nick]

Nick, so what's your present XXHE settings (Q1, buffer size and SFS)?

Marcin hi,


I have updated my signature after reading Mani's reminder 

EDIT

SFS is at 83 at the moment for me which gives a balance of detail without sound becoming too thin. Sounds like Peter has some suprises for us though regarding SFS 

EDIT


Nick.

[Marcin_gps]

Thanks, maybe increasing the buffer size is a good thing now, I'll check that.
I have to tell you, that after playing with IRQ affinity tool, I checked my sound card resources in device manager and I was amazed to see that it uses dedicated IRQ now - 11. (previously 23). I'm not sure it was the IRQ affinity settings though, because I haven't checked the IRQ of my card for a while now and in the mean time I applied a lot of tweaks, including disabling the whole bunch of devices - 'regular', system and hidden.

[Nick]

Marcin,

Weird but good news.

Out of interest you use PCI Lock (Control Panel > Administrative Tools > System configuration > Boot > Advanced Options)

http://www.osronline.com/ddkx/ddtools/bootini_419v.htm

Nick.

[Marcin_gps]

No, I don't use it, I tried it, but didn't work. Windows assigned virtual IRQ to my sound card at first startup and I couldn't do anything about it.

[Marcin_gps]

After many hours of listening, I'm disappointed with these affinity tweaks. The sound is to bright. I went back to my reference settings and the magic is back

IRQ8Priority=1
Win32Separation=28(40)

I tried IRQ11Priority, which is the IRQ of my sound card, but I didn't like the sound. (of course not parallel with Nick's affinity tweaks)

[Marcin_gps]

I wouldn't be myself if I hadn't checked this again - yep, I'm crazy  Anyway, this time I decided not to stick to Nick's settings and went a little bit wild applying almost everything to CPU0 (I left CPU, motherboard resources untouched though) and for sound card as well as PCI bus, I set mask to use two cores.  The result exceeded my expectations. So many details, but what struck me the most was the level of background information. I was listening to Diana Krall (24/96) and I couldn't believe my ears, I asked myself - 'is this noise'? Yep, noise from a mic is very clear now, later I played other hi-resolution stuff and I got the same feeling. This time nothing sharp about the sound. I think these settings could be fine-tuned, but I have to do a little research or perhaps you could tell me, what devices 'need  juice' during XXHE playback for PCI card. Maybe 'ati i/o communications processor pci bus controller'?

Cheers,
Marcin

[PeterSt]

Referring to this post : IRQ and Cores (look at the first picture in there) ...

I changed nothing to anything, except for that I changed the soundcard from PCI slot, that by itself causing the driver to (automatically) reinstall.
Now the driver is running in the 4th core, while before it was in the 3rd.

This will (?) tell that there's some "division" of Cores over PCI dealt-with slots, which may go over (via) the interrupt assignment to PCI slots.
Fact is, that if we are as far that the IRQ stuff for the soundcard (and/or the possibly related Core the driver code runs in) matters for SQ - the PCI slot used will matter to sound quality. Maybe if I change the card to another slot again, it will run in the same Core as the Sound Engine runs in ?

Anyway, where I said earlier that all automatically goes "just as I want with 4 Cores", this can't be said anymore.
This definitely makes the IRQ subject an important subject (again).

Peter

[Marcin_gps]

And from my experience once you apply your own affinity settings, there is no guarantee that system asign that same values if you decide to go back and remove your masks. I could swear that after messing with that settings, going back resulted in different sound.

[Josef]

This will (?) tell that there's some "division" of Cores over PCI dealt-with slots, which may go over (via) the interrupt assignment to PCI slots.

Cores are oblivious to both slots & interrupts.

AFAIK every PCI slot has multiple interrupts assigned (think 4) and each PCI card can use as many as it needs. But those interrupts are not what you see in OS. Hardware PCI IRQs are mapped via IRQ router on your motherboard into IRQs you see in OS.

In theory, you may be able to fix PCI IRQs mappings from your BIOS but that is not guaranteed to work as Windows is Plug-n-Play OS and can shift IRQs around as it sees fit. You may try disabling PnP of course, but that could lead to all kinds of other problems and in any case there is no need for any of this.

I may be wrong on some of the above (not my field) but it really is not that important for our needs as there is not much we can do about that process except to keep in mind that different PCI slots by design get mapped to different IRQs (as you just found out) so if you move stuff inside your machine you may need to re-visit Interrupt Affinity tool.

What is important from our perspective is where IRQs are handled in the end as, by they nature, they will _interrupt_ anything that is going on at the moment. And we probably don't want music player process being interrupted just when it is busy filling sound card's buffer especially if we are using ultra low latency do we?...
What follows is that higher latencies (=Adaptive mode) may not be as much affected as Special mode (may not even be perceptible although I believe it is) but as a matter of principle it makes sense to move everything possible out of time-sensitive process i.e. particular CPU core.

Since Windows by default will not give any guarantee which CPU will handle particular IRQs (as it tries to balance it out evenly between cores theoretically it could even switch it _during_ playback) that is the reason why we need Interrupt Affinity tool: to bring order to chaos and make sure time-sensitive things are not needlessly interrupted all the time.