Messages in this thread | | | Date | Tue, 17 Apr 2001 09:37:24 -0700 | From | Laurent Chavet <> | Subject | Is there a way to turn file caching off ? |
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Hi,
I'm running on a machine with 2GB of memory and dual PIII 550MHZ. Just after boot with "nothing else running": I run a program that almost like dd if=/dev/null of=/local/test count=10000 bs=1000000 Except that there is a thread for reading and a thread for writing. The program itself almost doesn't take any CPU. What's going on is top showing: First cache grows to the size of RAM (2GB) with transfer rate slowing down as the cache grows. Then the transfer rates drops a lot (2 to 3 time slower than the drive capacity) and there is a very high CPU usage of system time (more than a CPU) used by bdflush and kswapd (and some others like kupdated).
Of course my real application doesn't go from /dev/zero to file but it still only does sequential access, and it seems that I pay a high price for the file caching when I'm not using it at all.
Is there a way to turn file caching off, or at least limit its size ?
Thanks,
Laurent Chavet
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