Difference between revisions of "COMP 3000 Essay 2 2010 Question 3"
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Mode Switches speaks of moving from one medium to another. Specifically moving from the User Space mode to the Kernel mode or Kernel mode to User Space. It does not matter which direction or which modes we are swtiching from, this is simply a general term. | |||
System Call Pollution is a more sophisticated manner of speaking of wasteful or un-necessary delay in the system caused by system calls. This pollution is in direct correlation with the fact that the system call invokes a mode swtich which is not a costless task. | |||
Revision as of 15:02, 11 November 2010
3.FlexSC: Flexible System Call Scheduling with Exception-Less System Calls
Paper
The Title of the paper we will be analyzing is named "FlexSC: Flexible System Call Scheduling with Exception-Less System Calls". The authors of this paper consist of Livio Stores and Michael Stumm, both of which are from the University of Toronto. The paper can be viewed here, [1] for further details on specifics of the essay.
Background Concepts:
In order to fully understand the FlexSC paper, it is essential to understand the key concepts that are discussed within the paper. Here listed below, are the main concepts required to fully comprehend the paper.
A System Call is the gateway between the User Space and the Kernel Space. The User Space is not given direct access to the Kernel's services, for several reasons (one being security), hence System calls are the messengers between the User and Kernel Space.
- Processor Exceptions:
Synchronous Execution Model(System call Interface) refers to the structure in which system calls specifically are managed in a serialized manner. Moreover, the synchronous model completes one system call at a time, and does not move onto the next system call until the previous system call is finished executing.
Mode Switches speaks of moving from one medium to another. Specifically moving from the User Space mode to the Kernel mode or Kernel mode to User Space. It does not matter which direction or which modes we are swtiching from, this is simply a general term.
System Call Pollution is a more sophisticated manner of speaking of wasteful or un-necessary delay in the system caused by system calls. This pollution is in direct correlation with the fact that the system call invokes a mode swtich which is not a costless task.
System Call Batching is the concept of batching (i.e. grouping) system calls together. This idea is very similar to the counterpart of system calls in a sequential sequence. Groups are formed of system calls after the idea of batching has occurred instead of the initial individual system calls in a sequence.