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I've noticed kernel_task's disk usage is heavily skewed towards writes (e.g. 7GB read for 170GB written over a couple of hours). Assuming it is indeed swapping
by blep-arsh 6y ago
I've noticed kernel_task's disk usage is heavily skewed towards writes (e.g. 7GB read for 170GB written over a couple of hours). Assuming it is indeed swapping pages to disk and reads/writes are counted properly, either the dynamic pager or some application/system process are making extremely unfortunate life decisions. Lots of dirty pages are never read back, like there is a huge cache of... something.
- kevincox 6y agoIn general you will write out pages to swap before evicting them from memory. The goal is never having to wait for a page to finish being flushed to disk to allocate a new page. This means you will sometimes access a page that had been written out to disk but is still available to memory. If you modify it it may be written out again before being read. So it isn't unreasonable to have swap writes be higher than swap reads. However those numbers seem extreme probably some bad tuning or just neglecting to account for the full cost of writing to disk.