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ep:labs:02:contents:tasks:ex3 [2022/06/13 17:27]
radu.mantu
ep:labs:02:contents:tasks:ex3 [2022/09/13 11:58] (current)
radu.mantu [03. [30p] Kernel Samepage Merging]
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 <code bash> <code bash>
-# on Ubuntu you can usually find it on your /boot partition+# on Ubuntu you can usually find it in your /boot partition
 $ grep CONFIG_KSM /​boot/​config-$(uname -r) $ grep CONFIG_KSM /​boot/​config-$(uname -r)
 CONFIG_KSM=y CONFIG_KSM=y
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 Finally, look at the provided code, compile it, and launch the program. As an argument you will need to provide the number of pages that will be allocated and initialized with the same value. Note that not all pages will be de-duplicated instantly. So keep in mind your system'​s RAM limitations before deciding how much you can spare (1-2GB should be ok, right?) Finally, look at the provided code, compile it, and launch the program. As an argument you will need to provide the number of pages that will be allocated and initialized with the same value. Note that not all pages will be de-duplicated instantly. So keep in mind your system'​s RAM limitations before deciding how much you can spare (1-2GB should be ok, right?)
  
-The result should look something like this:+The result should look something like **Figure 1**:
  
-<​spoiler>​ +{{:​ep:​labs:​02:​contents:​tasks:​ksm_vmstat.png?​700|}} 
-{{:​ep:​labs:​02:​contents:​tasks:​ksm_vmstat.png?​700|}} ​| +<html><​center
-</spoiler+<​b>​Figure 1:</​b>​ <​b>​vmstat</​b>​ output during ​the execution of our sample program (unit of measure: MB). The free memory ​steadily decreases from a baseline value of ~4.5GB to a minimum of ~2.5GB after the process ​startsAs <b>ksmd</b> begins ​scanning ​and merging ​pages, the free memory ​steadily increasesWhen the process ​eventually ​terminates, the amount of free memory ​reverts ​to its initial ​value. 
- +</​center></​html>​
-Here, we can see the active ​memory ​suddenly rising when we start the process. ​Over the next few seconds, as **ksmd** starts ​scanning pages, the active ​memory ​slowly dropsFinally, as the process terminates, ​all memory is reclaimed by the kernel and the active ​memory ​returns ​to roughly the same value as before.+
  
 If you ever want to make use of this in your own experiments,​ remember to adjust the configurations of **ksmd**. Waking too often or scanning to many pages at once could end up doing more harm than good. See what works for your particular system. If you ever want to make use of this in your own experiments,​ remember to adjust the configurations of **ksmd**. Waking too often or scanning to many pages at once could end up doing more harm than good. See what works for your particular system.
ep/labs/02/contents/tasks/ex3.1655130443.txt.gz · Last modified: 2022/06/13 17:27 by radu.mantu
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