Hi! Dominik wrote:
> First, I replaced POSIX_FADV_DONTNEED with POSIX_FADV_WILLNEED and did > some performace checks: With the same arguments to posix_fadvise? That doesn't make sense because you're referencing the part of the file that has already been processed. > - Index generation takes quite the same time 1,1 GB in 17 seconds. > - Exporting on same hard disk is now done in 21 seconds instead of 34 > seconds! > =>That's really good! > > Now, I tried a 4,3 GB file. (may memory has "only" 3,3 GB) > - Index generation takes now 103 seconds instead of 49 seconds. (that's > what is called "thrashing") > - Exporting takes 100% longer (288 sec instead of 148 seconds) > => this is definitely not OK. Yep. [...] > Second (here is the interesting part ;-) ) > I tried the option POSIX_FADV_NORMAL. That would be the same as not calling posix_fadvise() at all. We already had that, and it wasn't good. > Now the system know itself and automatically(!) whether to hold the > video (...WILLNEED) or the don't hold the video (...DONTNEED) in memory. > => this ist the best parameter, because you get always the best perfomance! Only if dvbcut is the only application running. Most of the time, however, it isn't. In particular, if you run a DVB recorder on the same machine, you are calling for big trouble - they need quite some amount of RAM for buffering and low latency (no swapping or thrashing). Otherwise, the receiver buffer will overflow, which punches holes of several seconds into your recorded video. That's worse than a VHS recorder with a damaged tape. > PS: forget the new entry in .qt/dvbcut.sf.netrc. Just replace it with > POSIX_FADV_NORMAL. (Feel free to do some performance checks yourself :-) ) > PPS: I hope this works under Windows as goog as under Linux... If not, > keep the old ...DONTNEED for the windows port.) As far as I know, Windows doesn't have posix_fadvise(). -- Michael "Tired" Riepe <[EMAIL PROTECTED]> X-Tired: Each morning I get up I die a little ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ DVBCUT-user mailing list DVBCUT-user@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/dvbcut-user
