Page ins/outs

rAph

Registered
What are page ins/outs? Is that when it writes to the VM file? My page ins is really high (60,000 or so), but the outs is at 0. Is this normal? What's the difference between the two?
 
"Page Ins" are pages read into memory from disk -- but not necessarily the VM file on the disk... it could be as simple as launching a program that hasn't been launched before on this login, causing portions of the program to be read into memory, or "paged in."

"Page outs" are memory pages written to the disk, which is always (eh, 99.9%) the VM file. "Page outs" are one thing keep an eye on to gauge memory usage -- if your page outs are high, then you're swapping a lot of RAM to disk, which could indicate that you need or could use more.
 
Pageins occur anytime something is moved into Active RAM whether that is from Inactive RAM, the swapfile(s), or another file on the hard drive.

Pagouts occur anytime anything is moved out of Active RAM which includes mapping into Inactive RAM, as well as writing to a Swapfile. Only data is ever written to the hard drive since instructions are already on the hard drive.
 
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