[rrd-developers] rrdtool 1.3 update slowness

[Evan Miller]

I ran Tobi's perftest.pl against RRDtool 1.2 and the current subversion 
checkout. Updating a single RRD is noticeably faster under 1.3, but 
performance grinds to a halt on my machine once I get up to 100 or so 
RRDs. I consistently produce results similar to these:


RRDtool 1.2:

Create     10 rrds      1 c/s (0.00117 sdv)   Update     10 rrds   23288 
u/s (0.00002 sdv)
Create     10 rrds      1 c/s (0.00062 sdv)   Update     20 rrds   21125 
u/s (0.00065 sdv)
Create     20 rrds      1 c/s (0.00125 sdv)   Update     40 rrds   23385 
u/s (0.00002 sdv)
Create     40 rrds      1 c/s (0.00259 sdv)   Update     80 rrds   23150 
u/s (0.00005 sdv)
Create     80 rrds      3 c/s (0.41032 sdv)   Update    160 rrds   22688 
u/s (0.00006 sdv)
Create    160 rrds     10 c/s (0.02412 sdv)   Update    320 rrds   19940 
u/s (0.00124 sdv)
Create    320 rrds      5 c/s (0.02459 sdv)   Update    640 rrds   17601 
u/s (0.00142 sdv)
Create    640 rrds      3 c/s (0.04289 sdv)   Update   1280 rrds   10012 
u/s (0.00432 sdv)
Create   1280 rrds      1 c/s (0.35445 sdv)   Update   2560 rrds    4294 
u/s (0.00614 sdv)
Create    768 rrds      1 c/s (0.05230 sdv)   Update   3328 rrds    3626 
u/s (0.00785 sdv)


RRDtool 1.3:

Create     10 rrds      1 c/s (0.00771 sdv)   Update     10 rrds   31434 
u/s (0.00007 sdv)
Create     10 rrds      1 c/s (0.00421 sdv)   Update     20 rrds   29388 
u/s (0.00031 sdv)
Create     20 rrds      1 c/s (0.00937 sdv)   Update     40 rrds   24646 
u/s (0.00068 sdv)
Create     40 rrds      3 c/s (0.40489 sdv)   Update     80 rrds   16121 
u/s (0.00132 sdv)
Create     80 rrds      5 c/s (0.04052 sdv)   Update    160 rrds    2000 
u/s (0.00519 sdv)
Create    160 rrds      2 c/s (0.12109 sdv)   Update    320 rrds      33 
u/s (0.02963 sdv)

$ uname -a
Linux yossarian 2.6.20-16-generic #2 SMP Thu Jun 7 20:19:32 UTC 2007 
i686 GNU/Linux

I didn't configure with any special options. Ideas?

Evan