Re: [pve-devel] [PATCH manager] ceph osd: ui: show PGs per OSD

[Aaron Lauterer <a.lauterer@proxmox.com>]

Seems like the `osd df tree` call is about 25% slower, plus minus.

Tested on our AMD test cluster that is currently set up with 3 nodes with 4 OSDs 
each. 50k iterations.

root@jura1:~# ./bench.pl
                Rate osd-df-tree    osd-tree
osd-df-tree  9217/s          --        -27%
osd-tree    12658/s         37%          --
root@jura1:~# ./bench.pl
                Rate osd-df-tree    osd-tree
osd-df-tree  9141/s          --        -25%
osd-tree    12136/s         33%          --
root@jura1:~# ./bench.pl
                Rate osd-df-tree    osd-tree
osd-df-tree  9940/s          --        -23%
osd-tree    12987/s         31%          --
root@jura1:~# ./bench.pl
                Rate osd-df-tree    osd-tree
osd-df-tree  8666/s          --        -20%
osd-tree    10846/s         25%          --
root@jura1:~#

On 2/14/23 14:19, Thomas Lamprecht wrote:
> On 14/02/2023 09:13, Aaron Lauterer wrote:
>> By switching from 'ceph osd tree' to the 'ceph osd df tree' mon API
>> equivalent , we get the same data structure with more information per
> 
> the change looks almost too neat for using a completely different command,
> a bit fishy, but hey, if it works (roughly as fast) as the other one its
> fine to me.
> 
>> OSD. One of them is the number of PGs stored on that OSD.
>>
> 
> did you benchmark the both to compare for any bigger runtime difference?
> 
> E.g., some loop with a few thousands rados mon_command calls in perl for each
> using HiRes timer to measure total loop time and compare?
> 
> I'd not care for a few percent, but would be good to know if this is
> order of magnitudes slower - which I'd not expect, but its to easy to
> check to not do so IMO.