Hadd takes much longer in 5.24

ROOT
1

I’ve done a test adding two files a.root and b.root, each 2.2G. I compare the times to add them using hadd in root versions 5.24, 5.22, and 5.20 below, all 64-bit.

time hadd aplusb.root a.root b.root

Version 5.24 (64 bit)
real 29m16.634s
user 3m13.032s
sys 25m22.793s

Version 5.22 (64 bit)
real 1m50.372s
user 0m2.465s
sys 0m19.955s

Version 5.20 (64 bit)
real 1m3.823s
user 0m2.417s
sys 0m17.864s

Original post below:

Hello,

Is anyone familiar with hadd? I’ve been using it to merge files (TTree files, not just histograms) and it has worked very well. I recently moved to root version v5.24(64bit) and notice hadd takes much longer to complete than it used to in v5.18(32bit).

As a demonstration, I have 3 ntuples, fileA.root,fileB.root, and fileC.root. Each file is 1.2G.

When I do:
time hadd outfile.root fileA.root fileB.root fileC.root

these are the times I get:

ROOT v5.24 (64 bit)
real 22m18.719s
user 1m15.661s
sys 17m28.543s

ROOT v5.18 (32 bit)
real 0m48.092s
user 0m2.817s
sys 0m17.018s

22 minutes vs 48 seconds . . . ??? Any help is much appreciated.

Cheers,
Sean

2

Could you post your a.root and b.root files in some public area?

Rene

3

Hello,

I have moved the two files to

uaf-2.t2.ucsd.edu/~ssimon/rootfiles/

I hope this is viewable. The files are not named quite as simply as a.root and b.root, instead they are

prova_QCD_EMEnriched_Pt80to170_Summer09-MC_31X_V3_SD_Photon20-v1_GEN-SIM-RECO_1.root
prova_QCD_EMEnriched_Pt80to170_Summer09-MC_31X_V3_SD_Photon20-v1_GEN-SIM-RECO_2.root

Thanks for looking,
Sean

4

I now also moved these two files to lxplus227.cern.ch in the /tmp directory

[lxplus227] /afs/cern.ch/user/s/ssimon > ls /tmp/prova*
/tmp/prova_QCD_EMEnriched_Pt80to170_Summer09-MC_31X_V3_SD_Photon20-v1_GEN-SIM-RECO_1.root
/tmp/prova_QCD_EMEnriched_Pt80to170_Summer09-MC_31X_V3_SD_Photon20-v1_GEN-SIM-RECO_2.root
[lxplus227] /afs/cern.ch/user/s/ssimon >

Maybe that is more convenient.

Cheers,
Sean

5

Thanks for providing these files. The problem is now understood and fixed in the SVN trunk.
The fix will also be included in the 5.24 patches.

Rene

6

Great.

Thanks again.
Sean