well i researched a bit more, now i'll try dvbstream and vlc streaming. On Sun, Jun 17, 2012 at 10:48 AM, Emmanuel Touzery <[email protected]>wrote:
> Otherwise if someone is interested, for now I still can't make DVB-T > recording work smoothly. Ethernet was a big help but not quite enough. > > I've made quite some tuning, using mplayer instead of tzap+cat, and then > strongly prioritize that mplayer process: chrt 99 with FIFO scheduling, > nice -20, ionice -c1 (though i guess that last one doesn't make a real > difference), and even some scheduler tuning to increase latency and > prioritize real time processes: > > echo -1 > /proc/sys/kernel/sched_rt_runtime_us > echo 40000 > /proc/sys/kernel/sched_rt_period_us > echo 600000 > /proc/sys/kernel/sched_latency_ns > echo 400000 > /proc/sys/kernel/sched_min_granularity_ns > > I've also tried NFS, udp and tcp, with max block size (1Mb!), 32kb and > 64kb, but i still get cuts. > > I actually now get 15 minute blocks without cuts. But even only every 15 > minutes, a cut is a cut... > i also tried overclocking the pi without big differences (i actually > didn't try to overclock it on the latest settings but i guess it also > wouldn't help). > > i'll see, i'm still not quitting but getting closer :-/ > > emmanuel > > > On Thu, Jun 7, 2012 at 10:08 PM, Felix Lighter <[email protected]>wrote: > >> I'm glad that Ethernet helped the situation. >> Beware USB - it's also notorious for aggressively interrupting the CPU. >> 480Mbps USB2 comes at a high price, CPU-wise. And as you point out, >> it's already busy capturing video. >> >> I would definitely suggest looking into NFS, since you should be able >> to lighten the CPU load even further by increasing the write buffer >> size (in the mount options). Take a look and see whether Samba also >> offers any options for tuning network usage / bandwidth. >> >> Cheers, >> FL >> >> On 7 June 2012 15:43, Emmanuel Touzery <[email protected]> wrote: >> > Hello, >> > >> > Thanks for a lot for the tip. I tried quickly with a SMB share which I >> > already had setup and... yes it seems better! Although I really can't >> > believe it, it does seem to help. I'm glad you give me a plausible >> > explanation with DMA though, because that's the last thing I was >> expecting. >> > Especially since my network is not wired and though it's plugged using >> > ethernet on the pi, it reaches my computer through wifi. >> > >> > I'll try more. I didn't try much with USB keys too because I measured a >> > slightly lower throughput than with the SD card and I read that on the >> pi, >> > the throughput for USB+ethernet is shared. I figured, since USB is >> already >> > busy receiving the data from the video capture device, better save on >> the >> > SD... but apparently not. >> > >> > But really I can't conclude much until I test more. The first tests >> seems >> > to say network>usb>sd. but even on network I've seen a skip. Though >> it's on >> > a non-preempt kernel and without any sort of buffering (eg flywheel or >> > fifo), nor nice or chrt. >> > >> > Anyway, it seems there's not much hope of configuring something >> > differently on the driver or the kernel, so for now I'll focus on where >> to >> > save: SD, network, usb, with or without FIFO and so on. And maybe also >> NFS >> > vs SMB, if SMB doesn't always cut it. Definitely network appears the >> most >> > promessing option for now! So thanks again for the tip! >> > >> > emmanuel >> > >> > On Wed, Jun 6, 2012 at 10:27 PM, Felix Lighter <[email protected] >> >wrote: >> > >> >> Saving to a network share (e.g. NFS with intermediate block size) >> >> might perform better. >> >> The Ethernet port is likely to be much better served by the CPU's DMA >> >> facilities than its SD interface is. >> >> >> >> Cheers, FL >> >> >> > _______________________________________________ >> > pvrusb2 mailing list >> > [email protected] >> > http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2 >> _______________________________________________ >> pvrusb2 mailing list >> [email protected] >> http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2 >> > > _______________________________________________ pvrusb2 mailing list [email protected] http://www.isely.net/cgi-bin/mailman/listinfo/pvrusb2
