Is it advisable to have MySQL Master/Slave running on the same physical server, on the same mysqld, sharing the same disk? my Use-Case :

The solution I am developing is very data oriented. I run a cron job every 3 hrs to read lots of records from a file, process them and store them in the database. I also need to generate reports, which I do by querying database.

So, I was thinking of having MySQL replication in Master and slave so that I can do all the inserts / updates on Master and use the slave just to read data to generate reports.

I read this other post on the site and it got me thinking.

Here is my concern: Both my master and slave will be sharing the same resources here as they are on same physical server.

Is it good idea to do so?
I don't think so. You might reduce locking issues (but I'm not sure of that), but you are adding replication overhead without increasing your hardware resources, which means you'll be doing more with the same resources, which probably means decreased performance.