Somehow i came across some shiv puran pages in internet that vishnu had to meditate for thousands of years and worshipped very intensely to lord shiva to grant him the sudarshan chakra. I dont understand the significance of this. How does it prove that vishnu is superior to lord shiva. i am very much confused and seems to be lost in my concept of supremacy of krishna. kindly help me understand this my dear devotees of lord krishna.