[pypy-svn] r58046 - pypy/build/doc

[hpk at codespeak.net]

Author: hpk
Date: Wed Sep 10 19:18:48 2008
New Revision: 58046

Modified:
   pypy/build/doc/benchmark_memory.txt
Log:
revive some remarks from fijal


Modified: pypy/build/doc/benchmark_memory.txt
==============================================================================
--- pypy/build/doc/benchmark_memory.txt	(original)
+++ pypy/build/doc/benchmark_memory.txt	Wed Sep 10 19:18:48 2008
@@ -63,11 +63,18 @@
 -----------------------------
 
 Unless we can use some external tool we
-can parse info located in /proc/PID/smaps. 
-This provides detailed info, see e.g. here 
-for some explanations: 
+can parse info located in /proc/PID/smaps
+(beginning from linux 2.6.16) and contains
+Size, Rss, Shared and Private. 
 
-    http://bmaurer.blogspot.com/2006/03/memory-usage-with-smaps.html
+Note that all addresses are virtual, which means
+that having the same address in two processes 
+doesn't mean it's the same memory.
 
-For us mostly process private memory, RSS (Resident Set Size)
-and shared memory will be interesting to measure. 
+Explanation:
+Size: total (virtual) size of memory, possibly irrelevant
+RSS (Resident Set Size): indicates physically used RAM 
+Shared: memory shared with other processes. Note that this is simply a counter
+how many processes reference it. Memory can move private -> shared in case
+some other process will load the same library or so.
+Private: private memory owned by a process.