Messages in this thread | | | Date | Wed, 18 Mar 1998 08:55:16 -0800 (PST) | From | Jaime Fournier <> | Subject | Re: some memory/swap thoughts |
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Well you have a couple of points there. You might want to fiddle with different settings in /proc/sys/vm/freepages, and swapcntl.
I was able to solve my problem of lack of memory that way.
---Jan Gyselinck <JAN.GYSELINCK@student.kuleuven.ac.be> wrote: > > Hi all > > My experience comes from a 2.1.89 kernel. While the following may not > apply anymore, my conclusions will still apply for newer kernels, so read > on. > > A got a P75 portable with 16 megs. The memory-code (or the thing that > loves to put things in swap) in .89 thinks is should keep something like 5 > to 6 meg as a cache. That leaves me with 10 megs of memory, and some 1.5 > megs is already taken by the kernel. Imagine: you're compiling something, > you're bzipping something (and that needs 8.5 meg), so if you do that, > you'll know what swapping is. Even a sole bzip can't run without > swapping, with used to run without (or with some swapping in the > beginning, but never while running). > > I think that the people who designed this 'feature' did one thing wrong. > Namely they turned things around. Memory is not made to use if as a > cache, it's used to run programs from. Programs are not made to be run > from swap. > > Now, 5 meg as a cache, isn't that too much?? Some people think this is > needed, well I can tell you, it isn't. A year ago, I did some testing on > a 486DX33 with 8 meg, running DOS/winslows 3.11. I tried different > cache-sizes (with pc-cache) and measured the speedup while starting up > MS-Word. Maybe you think that's not the way to test this, but why not? > You test the speed-up in real-life applications, because that's what you > do all day. So, speedup from 0 to 64 kB cache, 20 seconds, from 64 to 128 > kB cache, 14 seconds, from 128 to 256 kB, 6 seconds, from 256 to 512 kB, 3 > seconds, and from 512 to 1024 kB, 1 second. Now why in gods name would > one want 5 meg of cache? It will increase the speed of disk-activity with > maybe 1 second of a 2,5 meg cache. My oppinion is that for 16 meg of > memory, the minimum-limit for a disk-cache should be 256kB, not 5 meg!! > > Okay, you say, but what about all those idling programs that are stuck in > memory, and just take up memory from the cache. I know, I know, there are > cases where it's needed to run such programs, but not always. People are > running to many idle programs these days! Why do you think there is a > inet-daemon? So that there don't need to be a dozen idle processes who > are checking if there isn't something knocking on there port. Running 6 > or more agetty's? There exists something like a console spawn daemon, you > push a key-combination, and there opens a new console. > > If I run a bash on a console, and I do something on another console for a > while, and I return to the first one, I want the bash-process to respond > immediatly to my key-strokes. I don't like to wait for it until it's > loaded from swap. My opinion is this: if I run something, it is because > it needs to run, and it must be able to respond immediatly. If this is > not so, I wont run it. I don't have memory to throw around, I need every > bit. (And no, memory for a portable is not that cheap) > > So think about this, when you people change something in the > memory-management of linux, because it'll run on low-budget and > high-budget systems... > > > Jan Gyselink > for the moment a swapping linux-user > > PS: i hope .90 is better, 'll try it tonight, but after I rebooted, > because my console is messed up by Xwindows, who didn't restore the state > after it finished (maybe caused by to much swapping?????) > > > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.rutgers.edu >
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