From mboxrd@z Thu Jan 1 00:00:00 1970 From: Benno Senoner Date: Mon, 23 Aug 1999 20:50:32 +0000 Subject: Re: Streaming disk I/O kills file buffering and makes Linux unusable Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-sound@vger.kernel.org On Mon, 23 Aug 1999, Andrea Arcangeli wrote: > On Mon, 23 Aug 1999, Benno Senoner wrote: > > >No , I'm not saying that there is a bug, I'm saying that the > >filebuffering works very well in almost all cases , except of reading large > >files from disk continuously. > > Could you check `vmstat 1` and verify if you have continous > swapin/swapout? (I bet yes) If I am right then you'll probably want to > apply this my patch and try again and notice the performance difference > with eyes. > > ftp://ftp.suse.com/pub/people/andrea/kernel-patches/my-2.2.12-final3/no-swapout-2.2.10-B > > Andrea No , have very little swapin/swapouts (only occasionally) when clicking on the xterm icon. Since I run on a 256MB RAM box, I have to wait 30-40sec for the xterm executable disappearing from buffers ( since I stream about 5MB/sec). After this time when I must wait up to 5-6sec from clicking to the icon to the actual launch of the xterm. Of course this is because the disk is under high load , and loads the executable slowly, but if I I click on the icon again after only a few secs (instead of waiting 30-40secs) the 2nd xterm starts up almost immediately since it's still cached, 200MB filebuffer buffer/5MB/sec = takes about 40secs to fill all buffers. Browsing the web while runnig the streaming app, becomes frustrating because you have no caching at all while working on a very slow disk (due to disk I/O). IMHO with direct I/O the rest of the system will remain quite snappy. regards, Benno.