problem:
When the user has a large number of http requests, springboot obtains the data uploaded by http through the Controller and the data in the http body. It is found that the data in the http body is inconsistent with the data in the http body uploaded by the user. Through analysis, it is found that using tcpdump in the network card The data in the http body restored from the captured data packet is consistent with the data uploaded by the user, and is different from the data in the http body obtained by springboot.
It means that there is an error in the process of data transmission from the network card to springboot.
Cause Analysis:
Spring boot uses Tomcat by default. I replaced Tomcat with Jetty, and found that the same problem still exists, and no other similar problems with spring boot have been found, so it may have nothing to do with spring boot.
Because the bottom layer of Tomcat is implemented through ServerSocket, and the bottom layer of Socket gets data from the network transport layer, it is speculated that the problem may lie between the data from the network card to the system.
So it is speculated that it may be a server problem. I replaced it with a different model machine and deployed the program. It was found that the problem was solved, so the verification was a server problem.
Later, I disabled the IOMMU of the previous server and found that the problem was solved, indicating that the problem was caused by enabling the IOMMU of the server.
solve:
Enter the bios, disable the server's IOMMU, and find that the problem is solved. Springboot obtains the data uploaded by http through the Controller and no more errors.
The explanation is indeed the problem of enabling IOMMU, but why enabling IOMMU caused an error in receiving network card data. It is speculated that there is an error in the IOMMU management network card memory address mapping process, but the specific reason may need to be further analyzed.