2011.04.23. 16:21:01-kor Krisztian VASAS írta: > On 2011.04.23. 14:29, Miklos Vajna wrote: > > On Fri, Apr 22, 2011 at 06:26:05PM -0500, James Buren<[email protected]> wrote: > >> Would it be wise to enable PAE on i686 if it is not already done? Just a > >> thought of something for 1.5. > > > > What are your arguments for it? > > > > Here are mines against it: > > > > - it's slow > > Yes, it _was_ slow, but now till 16GB there is no real slowdown I don't know the current status of this topic; my latest first-hand experience is about half a year old (or even older). Anyway, I have been playing with this PAE dance on four different boxes, which gave me (at least) three different classes of results (I think based on the motherboard, but I'm not a hardware guy). I was trying to make use of the 4 GB RAM that was installed, which is not possible with a 32-bit kernel and without PAE – so I was trying the PAE-enabled 32-bit kernel on all the boxes.
1. Best result: PAE-enabled kernel enabled me to make use of all the 4 GB RAM, without any side effects (eg. slowdown). 2. Worst result: PAE-enabled kernel enabled me to make use of all the 4 GB RAM, but with terrible slowdowns (it was better to go with only 3.2 GB of the RAM actually available). 3. "No" result: I could still only use 3.2 GB of the RAM, without other effects. Don't ask me the kernel version, nor mobo ID's; I can dig up the latter but I don't remember if they fell into this class or the other. > > - it affects systems where PAE is not needed Based on the above, it seems to be quite true: PAE-enabled kernel could help one user, but could make a different user's life hell in the same time. > > - show me a system with 4G of RAM whose CPU is not 64bit-capable Some googling could reveal the correct wording of a Linus' quote, which says something like that anything beyond 2 GB and still 32 bit is pure luck, in either way. > Just think a bit: if there is a system that needs more cpu power and > more ram, but the application does not support 64bit (probably a binary > application), the PAE can be useful. This is true – but I would run a 32-bit virtualized environment (or simply a 32-bit chroot, which is possible, too) on a 64-bit box if I wanted to make use of all the RAM _and_ use a 32-bit only app (most probably a blob like skype). Btw: skype is a weird animal: it's "64-bit" version needs multilib, which means it's a 32-bit app packaged into/for a(n already wicked) 64-bit environment. So to sum up my 2 pence, I vote against PAE, but vote for multilib (whatever that is in its deeps, as I'm newbie on this topic). -- Bye, Boobaa (CSÉCSY László) http://csecsy.hu _______________________________________________ Frugalware-devel mailing list [email protected] http://frugalware.org/mailman/listinfo/frugalware-devel
