Messages in this thread | | | Date | Fri, 5 Jun 1998 01:22:22 -0700 (PDT) | From | Dean Gaudet <> | Subject | unlink aggressively robs resources |
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I've noticed this with 2.1.84, .86, and .103 kernels. When you unlink large files on an ext2 disk, the machine becomes extremely choppy. Not only is disk bandwidth stolen almost completely for that operation, but the cpu also seems to be at a loss. The systems I'm using all have 512Mb of RAM, they're dual cpu, some are ppro 200s, some are p-ii 266s, some are p-ii 400s. They all have buslogic scsi, with ultrawide disks.
I don't really have numbers to show this. But it's pretty easy to reproduce these sorts of situations. For example, create a couple 512Mb files and delete them at the same time, while trying to accomplish anything else (like a compile in the background).
Other similar nonsense can be created with stuff like:
#!/bin/sh while dd if=/dev/zero of=foo.$$ bs=4096 count=16384 1>/dev/null 2>&1 \ && cat foo.$$ >/dev/null; do : done
Run a few of those at the same time. They will saturate the disk, and anything else trying to use the disk will have no hope.
I know this last example is abusive. But I don't think deleting large files is abusive.
I can guess what's going on... but I wouldn't mind hearing it from folks more familiar with the code.
Dean
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