SLB Senior Software Engineer interview questions

My interview was conducted for a position in Pune. They took six rounds including three technical interviews, one presentation and two Managerial/HRs. I was initially uninterested given the unusually long recruitment process but was convinced by their hiring parter to participate. Most interviews took around 30-45 minutes but the final technical interview took around one and half hour. The presentation round requires you to make a PPT on any recent critical solutions you provided. After investing so much time, there wasn't any feedback given on why my profile was dropped. Based on personal experience, I wouldn't advise anyone to spend such a long time if you come across the same recruitment pattern.