From mboxrd@z Thu Jan 1 00:00:00 1970 From: =?iso-8859-1?Q?Robert_Br=FCckmann?= Subject: Re: latency timer Date: Wed, 27 Feb 2002 08:45:39 +0100 Message-ID: <000f01c1bf62$c598a4e0$0300a8c0@wgilmenau> References: <200202262315.SAA07930@renoir.op.net> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: Paul Davis , alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org > look, i've been recording huge chunks of data from a hammerfall for a > couple of years, and my code is all out there for people to look > at. i've even written JACK (with some help) to simplify the issue of > writing such applications. no, i wouldn't do what you're doing. i > wouldn't use the read/write API, for a start. > > i have never used the ALSA "multi" PCM devices, so i can't comment on > how well they will work either. its possible that they add some > additional performance penalty that affects you. So what do think I should use instead? I need all 48 channels in perfect sync (sample-accurate). Do you think that's impossible? The CPU-load of my application is (with signal processing) less than 30%, but still there are xruns sometimes. It might be that the pci bus can't handle my data. > > i've never recorded more than 26 channels, but i've done that *to > disk* using less than 30% of the available CPU with no xruns in sight > at the lowest period size. i also regularly run jackd in > all-input-monitor mode, copying data for all 26 channels, and that > doesn't consume more than 10-15% of the available CPU. this is on a > dual PII-450. > If I run my program with only one hammerfall, then the CPU load is less than 10%, no xruns at all. Maybe the problem is not the 48 channels but the syncing of the two hammerfalls. > there is absolutely no reason to be messing around with the PCI bus > settings to do multitrack recording. > But if the pci-bus is overloaded with the data it has to handle? It's a fact that it worked only since I increased the pci-latency timer in the BIOS. I am used to have these pci-performance problems with hardware from creamware (under win98 however, but it was hardware-related), these cards needed a lot of pci-bandwidth, too. I wonder if I'm the first one who wants to use two hammerfalls in linux for recording and playback at the same time. Anyone? Robert _______________________________________________ Alsa-devel mailing list Alsa-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/alsa-devel