Hacker News Reader

Comment by kalleboo | Hacker News Reader

I still ended up with an 8 GB page file after a few days of regular usage (nothing too hard like VMs or anything - just your typical Xcode dev workflow, including opening up Photoshop once or twice to export graphics).

This is on a MBP with 8 GB RAM.

I never had any memory-related performance issues in Lion, (maybe because I have an SSD), but I always end up with a big pagefile of stale data.

View on HN

Most modern operating systems try write the contents of the physical memory to the page file at the first good opportunity (well before it's needed) in order to save time when the page is actually paged out, so it's perfectly normal to have a page file that is at least as large as your physical memory.

AFAIK VMS and NT behave that way but Linux is much lazier. Especially if your swap is dynamically allocated (as in OS X) you don't want to swap out unless there is actual memory pressure.

The size of your page file isn't a sign of a performance problem. What matters is how often your paging out and in between disk and memory. That will result in a huge slow down in human-perceived performance.

The OP (and others, including myself) have observed a noticeable drop in the delays caused by frequent paging in and out. I checked and my pagefile is the same size as on Lion. Perhaps ML is still paging frequently, but if so, they've found a way to do it so that I'm not noticing it. Everything just feels faster compared to Lion.

Are you sure that's not your sleep image?

I'm going by the stat in iStatmenus. It slowly grows from 0 the first 2-3 days.

you sure it's the page file? page file or hibernation (safe sleep) file? Memory swaps to /var/vm/pagefile0 etc....

unless you disabled it deliberately through a 3rd party tool or command line, your macbook will dump all of RAM to disk as soon as it sleeps - this is your "safe sleep" recovery if power drops too low. It doesn't wait around for low power to dump it out, it does it as soon as you close the lid.

Reply on news.ycombinator.com