"Does it create a log if you just give it a --logfile log.txt?" <--- yes it does
It didnt work for me too so I used the command line I found on stackexchange
setx GPU_MAX_HEAP_SIZE 100
setx GPU_MAX_USE_SYNC_OBJECTS 1
setx GPU_MAX_ALLOC_PERCENT 100
setx GPU_MAX_SINGLE_ALLOC_PERCENT 100
@echo off
cd %~dp0
for /f "tokens=2 delims==" %%a in ('wmic OS Get localdatetime /value') do set "dt=%%a"
set "YY=%dt:~2,2%" & set "YYYY=%dt:~0,4%" & set "MM=%dt:~4,2%" & set "DD=%dt:~6,2%"
set "HH=%dt:~8,2%" & set "Min=%dt:~10,2%" & set "Sec=%dt:~12,2%"
set "datestamp=%YYYY%%MM%%DD%" & set "timestamp=%HH%%Min%%Sec%"
set "fullstamp=%YYYY%-%MM%-%DD%_%HH%-%Min%-%Sec%"
set fullstamp=%fullstamp: =%
set fullstamp=%fullstamp:,=.%.txt
cls
SRBMiner-CN.exe --config config-xmr.txt --pools pools-ocean.txt --logfile %fullstamp%
you will get the logfile in format of yyyy-mm-dd_hh-mm-ss.txt