On 2013-06-03 23:46, Roger Oberholtzer wrote:
On Mon, 2013-06-03 at 11:57 -0700, Linda Walsh wrote:
3) I get the impression that you are collecting more data for the same records, such that each (or significantly many) records are growing beyond the original space allocated for such records. So, while the system starts by buffering while it looks for space to hold the additional information (possibly at the end of the disk), when the buffers fill the OS kicks in to free space, and forces a long wait while new space is sought for each buffer it wants to empty -- forcing a length search for free blocks that won't be near your present data, but most likely at the end of it. Does that sound about right?
It is a binary file that grows and grows (up to 2 GB, which is the max file size we allow). The file contains a stream of JPEG images. One after another. Each image is 1920 x 450. There are 50 of these per second at max speed. The system has no problem doing this. It can work fine for 30 minutes. Then a single compress suddenly takes 4 or 5 seconds. If I write to /dev/null instead of a physical file, the compress per image stays a constant 10 milliseconds. It is only when I fopen/fwrite a real file on an XFS disk that this happens.
It does look as if XFS is doing some restructuring. I would try allocating the 2GB in advance. Try the XFS mail list. They should know. -- Cheers / Saludos, Carlos E. R. (from oS 12.3 "Dartmouth" GM (rescate 1)) -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org To contact the owner, e-mail: opensuse+owner@opensuse.org