-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 On 01/22/08 22:54, Rick Thomas wrote: > The rule of thumb comes from UNIX days (BSD and even before that with > AT&T UNIX). In order to be completely sure you would be able to swap > out a program when memory became full, UNIX allocated a page of swap for > every page of virtual memory a program occupied. So if vi required 256K > to run, there was 256K of swap space allocated to it. The 2 to 1 ratio > came from the observation that a busy UNIX time-sharing system with lots > of users ran most of it's time with half the users doing something that > required CPU/memory resources and the other half thinking, so you could > afford to overcommit memory by a factor of two.
Good to know the history. > These days, Linux uses a less straightforward, but in some ways more > effective, algorithm for deciding when and where to swap. That combined > with the availability of large cheap memory and lots of bloated programs > to fill it up, and users who expect instant response, has made the old > rule of thumb obsolete. But old habits die hard, and you often hear the > old rules of thumb quoted without thinking where they came from. > > On my own systems, I make swap huge (10 GB or more for 1 GB RAM -- Disk > is cheap!) so I can mount /tmp on a tmpfs filesystem. ???? Is this for apps that say "if malloc() fails, I create a tmp file"? IOW, you pretty much ensure that malloc() will never fail? - -- Ron Johnson, Jr. Jefferson LA USA "I'm not a vegetarian because I love animals, I'm a vegetarian because I hate vegetables!" unknown -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.6 (GNU/Linux) iD8DBQFHluFeS9HxQb37XmcRAk8qAJ4uMKPgzdlzoXW7V28xnqBLydn4GQCfZdLb 8Gpb4PEcfiVBaRYDffRg/Uc= =GD4Q -----END PGP SIGNATURE----- -- To UNSUBSCRIBE, email to [EMAIL PROTECTED] with a subject of "unsubscribe". Trouble? Contact [EMAIL PROTECTED]
