<div dir="ltr">Dear QE users and developers,<div><br></div><div> I am doing an electron-phonon coupling calculation in this way (I am using QE v 6.6).</div><div>First, I have done an scf calculation. Then, I have done a phonon calculation where I have printed the dvscf files, with</div><div><br></div><div>  fildvscf     = 'dvscf'<br></div><div>  </div><div>Subsequently, I have done the electron-phonon calculation changing the k-mesh grid, with</div><div><br></div><div>  trans       = .false.<br></div><div>  electron_phonon  = 'simple'<br></div><div><br></div><div>The calculation ends correctly, but for some q points I have noticed a huge difference between </div><div>CPU and Wall time, like</div><div><br></div><div>PHONON    :   15h55m CPU  3d18h56m WALL<br></div><div><br></div><div>>From the report at the end of the output, the I/O davcio routine seems to be the</div><div>"guilty":</div><div><br><br><div>  General routines<br>   davcio    :   107.89s CPU 263856.08s WALL (  520331 calls)</div><div></div><br>   Parallel routines<br> <br>   Electron-phonon coupling<br>   elphon    :  41730.55s CPU 309708.87s WALL (    1 calls)<br>   elphel    :  41671.20s CPU 309625.04s WALL (    60 calls)<br> <br>   General routines<br>   davcio    :   107.89s CPU 263856.08s WALL (  520331 calls)</div><div><br> This calculation was done with 10 processors and npool = 10, if I use 40 processors and npool = 10 it is worse (as can probably be expected due to the higher number of I / O operations). I have looked at the documentation but I am not very familiar with these things, thus I still have several doubts. Any suggestions on tests to do or how to improve performance, or at least comments to clarify the problem, would be greatly appreciated. <br></div><div><br></div><div>Thank you for your time,</div><div><br></div><div>Best,</div><div>Raffaello Bianco</div><div><br></div><div><br></div></div>