Hi, On Sat, Nov 7, 2009 at 12:19 PM, John McCabe-Dansted <[email protected]> wrote: > Hi, I have read > http://code.google.com/p/compcache/wiki/StatsExplained > and I can see why OrigDataSize could be larger than the figure > reported in /proc/swaps. However I am getting the reverse and I don't > know why I would have a smaller OrigDataSize than the figure reported > in /proc/swaps. > > From gpl2mem_150 (Attached): > > -- > > Filename Type Size Used > Priority > /dev/ramzswap0 partition 376116 376084 100 > /dev/sdb1 partition 2096440 54344 -1 > > DiskSize: 376120 kB > NumReads: 1296 > NumWrites: 94343 > FailedReads: 0 > FailedWrites: 0 > InvalidIO: 0 > NotifyFree: 0 > PagesDiscard: 0 > ZeroPages: 69734 > GoodCompress: 76 % > NoCompress: 1 % > PagesStored: 24295 > PagesUsed: 8658 > OrigDataSize: 97180 kB > ComprDataSize: 33636 kB > MemUsedTotal: 34632 kB >
OrigDataSize should probably be renamed to "NonZeroDataSize". Data stored in ramzswap is actually: OrigDataSize + ZeroPages*4. So, in your case this is: 97180 + 69734*4 = 376116KB which is less than 376084KB as reported by /proc/swaps The reason for not adding ZeroPages when reporting OrigDataSize is that it can give false impression of very high compressibility of memory data. Thanks, Nitin _______________________________________________ linux-mm-cc mailing list [email protected] http://lists.laptop.org/listinfo/linux-mm-cc
