Re: Q: Interesting memory usage stat's
On Sun, May 28, 2000 at 01:06:10PM +0300, Ira Abramov wrote: and I have a slightly related Q... lately I needed to hand in a few Java Applets as excercises for school, I sadly turned on Java support in Netscape, knowing it will get it stuck (and it does get stuck a lot, eating 99% of the CPU, leaking memory and eating the entire swap partition, dies only with SIG 9) the problem is that many times the netscape process leaks over 200Meg of swap, but it remains "used" once I kill the process. the RAM is freed, but the machine is heavy as hell because it won't free up the swap and swap back in all the other apps. I think it's the kernel's speed consideration to not move stuff around from disk without need. When those other app's procs wanna run again, the hardware will need them back in RAM so they'll all slowly return while the buffer space is given up. No use to force it, if it's done on demand. Well, atleast in theory :) Now, how my Linux manages to go into 2MB swap, with 160MB physical RAM, 70MB of them in buffers is still a mystery to me ... yet another optimization consideration? :) -- Best regards, Ilya Konstantinov a.k.a Toastie = To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
RE: Q: Interesting memory usage stat's
Now, how my Linux manages to go into 2MB swap, with 160MB physical RAM, 70MB of them in buffers is still a mystery to me ... yet another optimization consideration? :) But ofcourse. Suppose you open an app that is very heavy on memory usage. Sure enough - almost everything is thrown into the swap - to make space for Mozilla/JBuilder Then you close it. Memory is free again - but the kernel only reads from swap to memory on need. So not many pages from swap are called, and the kernel is using the free space for cache/buffers. = To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Q: Interesting memory usage stat's
IK Now, how my Linux manages to go into 2MB swap, with 160MB physical RAM, IK 70MB of them in buffers is still a mystery to me ... yet another IK optimization consideration? :) Very simple. Unused processes are better in swap. Look how many mgetty's you have? How ofter you use them? What about some gdm leftover from login, just waiting for your logout next month? And here is lpd for me printing once a week... All those are perfect candidates for swap hybernation. -- [EMAIL PROTECTED] \/ There shall be counsels taken Stanislav Malyshev /\ Stronger than Morgul-spells phone +972-3-9316425/\ JRRT LotR. http://sharat.co.il/frodo/ whois:!SM8333 = To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Q: Interesting memory usage stat's
On Sun, 28 May 2000, Nathan Fain wrote: Just recently I started generating graph's of system resource usage on some of my linux machines.On a certain group of machines I noticed a steady level of between 90% and 100% memory usage (while at the same time, swap and I have a slightly related Q... lately I needed to hand in a few Java Applets as excercises for school, I sadly turned on Java support in Netscape, knowing it will get it stuck (and it does get stuck a lot, eating 99% of the CPU, leaking memory and eating the entire swap partition, dies only with SIG 9) the problem is that many times the netscape process leaks over 200Meg of swap, but it remains "used" once I kill the process. the RAM is freed, but the machine is heavy as hell because it won't free up the swap and swap back in all the other apps. any idea how I force the machine to reclaim swap memory from dead processes? = To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Q: Interesting memory usage stat's
NF 1) Why is memory usage so high when it shouldn't be? NF Note: looking at the process that are running (most httpd), they don't NF amount to much more that 30mb. Actually, in ideal case memory usage should be 100%. Why you need memory that isn't used? If it isn't used by the processes, OS could use it as cache memory. However, I think it's very tough to make system that will get close to 100% memory usage, especially in general case. However, if the process configuration is static (i.e., same long-lived processes run again and again doing the same stuff), memory usage could be close to it - that means Linux is doing great job utilizing your memory. You should start worrying about memory only if swap usage grows and running processes start getting swapped - it easily leads to catastrophics thrashing and loads about 20+, basically meaning the system is dead. NF 2) How can I determine TRUE memory usage? Well, take "used" number, take out "cached" and "buffers". That should be close to it. -- [EMAIL PROTECTED] \/ There shall be counsels taken Stanislav Malyshev /\ Stronger than Morgul-spells phone +972-3-9316425/\ JRRT LotR. http://sharat.co.il/frodo/ whois:!SM8333 = To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Q: Interesting memory usage stat's
IA the problem is that many times the netscape process leaks over 200Meg of IA swap, but it remains "used" once I kill the process. the RAM is freed, IA but the machine is heavy as hell because it won't free up the swap and IA swap back in all the other apps. IA any idea how I force the machine to reclaim swap memory from dead IA processes? Are you sure it's indeed what happens? Is that netscape lying in swap, not other apps? Usually actively running app (99% CPU) is forcing other, sleeping processes out to swap and takes their memory for it. If they continue to sleep, they remain in swap - system won't resurrect them back to real memory unless they'll run. -- [EMAIL PROTECTED] \/ There shall be counsels taken Stanislav Malyshev /\ Stronger than Morgul-spells phone +972-3-9316425/\ JRRT LotR. http://sharat.co.il/frodo/ whois:!SM8333 = To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
Re: Q: Interesting memory usage stat's
Ira Abramov wrote: the problem is that many times the netscape process leaks over 200Meg of swap, but it remains "used" once I kill the process. the RAM is freed, but the machine is heavy as hell because it won't free up the swap and swap back in all the other apps. any idea how I force the machine to reclaim swap memory from dead processes? That seems unlikely. Swapped applications cannot run, they have to be swapped back in for them to run (the appropriate pages that pagefault, anyhow). There is no need to _force_ the kernel to reclaim swap space, as that's kind of meaningless (dead processes, even zombies already give up their memory, and that obviously includes swap). There is no actual reason to free up the swap space, as it's not really getting used right now. However, it does seem to me that this might go deeper. Is it just slow, or does it give out any error messages? Try recompiling the kernel, or anything large enough with multiple compiler processes (with make -j) and watch the memory usage and error messages. The 2.2.x tree (and those before) have a serious memory handling problem, they don't defragment the memory (or rather, allocate it in a dumb way - 1 page at a time). Maybe it's just running out of blocks? -- /-- Omer Efraim ---\ /--- [EMAIL PROTECTED] (remove spam_me) \ | I can picture in my mind a world without war, a world | | without hate. And I can picture us attacking that world, | | because they'd never expect it.| \-- Jack Handey, Deep Thoughts / = To unsubscribe, send mail to [EMAIL PROTECTED] with the word "unsubscribe" in the message body, e.g., run the command echo unsubscribe | mail [EMAIL PROTECTED]
