Thanks for the hint!

For example, if I have this kind of output, what value should I pass to the -work option?

Code:

fac: setting target pretesting digits to 182.15
fac: t15: 1.07
fac: t20: 0.04
fac: estimated sum of completed work is t15.19
fac: work done at B1=11000: 0 curves, max work = 74 curves
fac: 74 more curves at B1=11000 needed to get to t182.15
ecm: found prp16 factor = 6586291483612179
fac: setting target pretesting digits to 177.54
fac: t15: 1.73
fac: t20: 0.15
fac: estimated sum of completed work is t15.73
fac: work done at B1=11000: 8 curves, max work = 74 curves
fac: 66 more curves at B1=11000 needed to get to t177.54
ecm: 72/72 curves on C577, B1=11K, B2=gmp-ecm default
fac: setting target pretesting digits to 177.54
fac: t15: 7.73
fac: t20: 1.12
fac: t25: 0.05
fac: estimated sum of completed work is t20.26
fac: work done at B1=50000: 0 curves, max work = 214 curves
fac: 214 more curves at B1=50000 needed to get to t177.54
ecm: 216/216 curves on C577, B1=50K, B2=gmp-ecm default, ETA: 4 sec
pm1: starting B1 = 3750K, B2 = gmp-ecm default on C577
fac: setting target pretesting digits to 177.54
fac: t15: 38.59
fac: t20: 11.40
fac: t25: 1.06
fac: t30: 0.07
fac: estimated sum of completed work is t25.34
fac: work done at B1=250000: 0 curves, max work = 430 curves
fac: 430 more curves at B1=250000 needed to get to t177.54
ecm: 432/432 curves on C577, B1=250K, B2=gmp-ecm default, ETA: 20 sec
pm1: starting B1 = 15M, B2 = gmp-ecm default on C577
fac: setting target pretesting digits to 177.54
fac: t15: 124.99
fac: t20: 65.40
fac: t25: 9.70
fac: t30: 1.07
fac: t35: 0.09
fac: estimated sum of completed work is t30.46
fac: work done at B1=1000000: 0 curves, max work = 904 curves
fac: 904 more curves at B1=1000000 needed to get to t177.54
ecm: 904/904 curves on C577, B1=1M, B2=gmp-ecm default, ETA: 1.4 min
fac: setting target pretesting digits to 177.54
fac: t15: 426.32
fac: t20: 246.20
fac: t25: 54.90
fac: t30: 8.73
fac: t35: 1.09
fac: t40: 0.11
fac: estimated sum of completed work is t35.56
fac: work done at B1=3000000: 0 curves, max work = 2350 curves
fac: 2350 more curves at B1=3000000 needed to get to t177.54
ecm: 424/2352 curves on C577, B1=3M, B2=gmp-ecm default, ETA: 14.67 hrs hrs