[rrd-developers] rrdcached performance with >200k nodes

[kevin brintnall]

On Wed, Jan 13, 2010 at 05:21:57PM +0100, Mirek Lau?? wrote:
> there is about 224k nodes in the tree, after issuing FLUSHALL
> it takes about 20 minuts (with -t 8) to write almost all nodes

This sounds about right.

> we're now stuck at approx 10k nodes in queue,
> journal continues to write, updates are received at normal rate

Try issuing the "QUEUE" command to the daemon when in this state.  I just
want to verify that you are seeing files continually added to the end of
the queue, and being removed from the front.

>   PID USERNAME  THR PRI NICE   SIZE    RES STATE  C   TIME    CPU COMMAND
> 91510 portax     60  44    0   133M 90052K select 3   0:00 102.10% rrdcached

What does 'top -H' show for this pid?  Is the CPU spread out evenly or
dominated by one thread?  Since it's so close to 100%, I'm guessing one
thread.  It would be nice to determine whether it's the thread that's
handling your UPDATE (vs. the queue threads).

Also, can you repeat the earlier 'callgrind' output, but with --tree=both ?

-- 
 kevin brintnall =~ /kbrint at rufus.net/