I have 4GB of RAM and can quite easily use it all with Firefox, virtual machines, etc. I have a 4GB swap partition. But when I'm short of RAM and the swap gets used, performance is so bad it's practically unusable - the system will take 30s to respond to a window action, minutes to respond to a change of virtual desktop, etc. Even going to a tty console is very slow. Load average (as reported by uptime, tload, etc) goes through the roof.
Is this true for everyone? Obviously swap is going to be significantly slower than RAM, but does anyone find that it's actually acceptable for occasional use?
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Some more background:
I keep an eye on free memory and swap use with the System Load Viewer widget.
I've tried a swap file in addition to (at higher priority than) the swap partition - no practical difference.
I've tried vm.swappiness at 60 and at 10 and at 80 - no practical difference.
Recently I tried disabling swap altogether (thinking because it's close to unusable, I'd rather have out of memory errors). But when free memory ran low, I got exactly the same symptoms, suggesting that it's something to do with the OS "thrashing" with memory pages and not specifically due to swapping. I've been using the stress tool to simulate memory and other kinds of load.
memtest86 reports no errors; disk tests report no errors.
CPU is Intel(R) Core(TM)2 Duo CPU T6670 @ 2.20GHz; Kubuntu 11.10 64 bit.
I plan to buy more RAM anyway, but I also have an LCD panel issue and a battery issue so I'm thinking of a new desktop instead. And an SSD drive!
Is this true for everyone? Obviously swap is going to be significantly slower than RAM, but does anyone find that it's actually acceptable for occasional use?
-----------------------
Some more background:
I keep an eye on free memory and swap use with the System Load Viewer widget.
I've tried a swap file in addition to (at higher priority than) the swap partition - no practical difference.
I've tried vm.swappiness at 60 and at 10 and at 80 - no practical difference.
Recently I tried disabling swap altogether (thinking because it's close to unusable, I'd rather have out of memory errors). But when free memory ran low, I got exactly the same symptoms, suggesting that it's something to do with the OS "thrashing" with memory pages and not specifically due to swapping. I've been using the stress tool to simulate memory and other kinds of load.
memtest86 reports no errors; disk tests report no errors.
CPU is Intel(R) Core(TM)2 Duo CPU T6670 @ 2.20GHz; Kubuntu 11.10 64 bit.
I plan to buy more RAM anyway, but I also have an LCD panel issue and a battery issue so I'm thinking of a new desktop instead. And an SSD drive!
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