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@@ -280,4 +280,63 @@ of other objects.
+Extended slabinfo mode and plotting
+The slabinfo tool has a special 'extended' ('-X') mode that includes:
+ - Slabcache Totals
+ - Slabs sorted by size (up to -N <num> slabs, default 1)
+ - Slabs sorted by loss (up to -N <num> slabs, default 1)
+Additionally, in this mode slabinfo does not dynamically scale sizes (G/M/K)
+and reports everything in bytes (this functionality is also available to
+other slabinfo modes via '-B' option) which makes reporting more precise and
+accurate. Moreover, in some sense the `-X' mode also simplifies the analysis
+of slabs' behaviour, because its output can be plotted using the script. So it pushes the analysis from looking through
+the numbers (tons of numbers) to something easier -- visual analysis.
+To generate plots:
+a) collect slabinfo extended records, for example:
+ while [ 1 ]; do slabinfo -X >> FOO_STATS; sleep 1; done
+b) pass stats file(-s) to script:
+The script will pre-processes the collected records
+and generates 3 png files (and 3 pre-processing cache files) per STATS
+ - Slabcache Totals: FOO_STATS-totals.png
+ - Slabs sorted by size: FOO_STATS-slabs-by-size.png
+ - Slabs sorted by loss: FOO_STATS-slabs-by-loss.png
+Another use case, when slabinfo-gnuplot can be useful, is when you need
+to compare slabs' behaviour "prior to" and "after" some code modification.
+To help you out there, script can 'merge' the
+`Slabcache Totals` sections from different measurements. To visually
+compare N plots:
+a) Collect as many STATS1, STATS2, .. STATSN files as you need
+ while [ 1 ]; do slabinfo -X >> STATS<X>; sleep 1; done
+b) Pre-process those STATS files
+c) Execute in '-t' mode, passing all of the
+generated pre-processed *-totals
+ -t STATS1-totals STATS2-totals .. STATSN-totals
+This will produce a single plot (png file).
+Plots, expectedly, can be large so some fluctuations or small spikes
+can go unnoticed. To deal with that, `' has two
+options to 'zoom-in'/'zoom-out':
+ a) -s %d,%d overwrites the default image width and heigh
+ b) -r %d,%d specifies a range of samples to use (for example,
+ in `slabinfo -X >> FOO_STATS; sleep 1;' case, using
+ a "-r 40,60" range will plot only samples collected
+ between 40th and 60th seconds).
Christoph Lameter, May 30, 2007
+Sergey Senozhatsky, October 23, 2015