摘要:
A system and method for dynamically altering a Virtual Memory Manager (VMM) Sequential-Access Read Ahead settings based upon current system memory conditions is provided. Normal VMM operations are performed using the Sequential-Access Read Ahead values set by the user. When low memory is detected, the system either turns off Sequential-Access Read Ahead operations or decreases the maximum page ahead (maxpgahead) value based upon whether the amount of free space is simply low or has reached a critically low level. The altered VMM Sequential-Access Read Ahead state remains in effect until enough free space is available so that normal VMM Sequential-Access Read Ahead operations can be performed (at which point the altered Sequential-Access Read Ahead values are reset to their original levels).
摘要:
Administration of locks for critical sections of computer programs in a computer that supports a multiplicity of logical partitions that include determining by a thread executing on a virtual processor executing in a time slice on a physical processor whether an expected lock time for a critical section of the thread exceeds a remaining entitlement of the virtual processor in the time slice and deferring acquisition of a lock if the expected lock time exceeds the remaining entitlement.
摘要:
Methods, systems, and media are disclosed for improved granularity of a response-request communication on a networked computer system. One example embodiment includes receiving the request-response communication by the networked computer system, and associating the request-response communication with a port, having a nodelay setting, from a set of ports on the networked computer system. Further, the example embodiment includes enabling, based upon the associating, the nodelay setting upon connection of the request-response communication with the port. Further still, the example embodiment includes sending, in accordance with the enabling, the request-response communication to a destination in communication with the networked computer system. In addition, further example embodiments include configuring the ports on the networked computer system with nodelay values indicating whether a particular port is assigned nodelay or no nodelay for a request portion or request portion of a request-response communication connecting to that particular port.
摘要:
A system, apparatus and method of reducing adverse performance impact due to migration of processes from one processor to another in a multi-processor system are provided. When a process is executing, the number of cycles it takes to fetch each instruction (CPI) of the process is stored. After execution of the process, an average CPI is computed and stored in a storage device that is associated with the process. When a run queue of the multi-processor system is empty, a process may be chosen from the run queue that has the most processes awaiting execution to migrate to the empty run queue. The chosen process is the process that has the highest average number of CPIs.
摘要:
Scheduling threads in a multi-processor computer system including establishing an interrupt threshold for a thread, where the interrupt threshold represents a maximum permissible number of interrupts during thread execution on a processor; executing the thread on a current processor, where the thread has thread affinity for one or more processors including the current processor; counting a number of interrupts during execution of the thread on the current processor; and removing thread affinity for the current processor in dependence upon the counted number of interrupts and the interrupt threshold.
摘要:
A computer implemented method, apparatus, and computer usable code for managing cache data. A partition identifier is associated with a cache entry in a cache, wherein the partition identifier identifies a last partition accessing the cache entry. The partition identifier associated with the cache entry is compared with a previous partition identifier located in a processor register in response to the cache entry being moved into a lower level cache relative to the cache. The cache entry is marked if the partition identifier associated with the cache entry matches the previous partition identifier located in the processor register to form a marked cache entry, wherein the marked cache entry is aged at a slower rate relative to an unmarked cache entry.
摘要:
A system and method is provided for delaying a priority boost of an execution thread. When a thread prepares to enter a critical section of code, such as when the thread utilizes a shared system resource, a user mode accessible data area is updated indicating that the thread is in a critical section and, if the kernel receives a preemption event, the priority boost that the thread should receive. If the kernel receives a preemption event before the thread finishes the critical section, the kernel applies the priority boost on behalf of the thread. Often, the thread will finish the critical section without having to have its priority actually boosted. If the thread does receive an actual priority boost then, after the critical section is finished, the kernel resets the thread's priority to a normal level.
摘要:
A system, apparatus and method of reducing cache thrashing in a multi-processor with a shared cache executing a disruptive process (i.e., a thread that has a poor cache affinity or a large cache footprint) are provided. When a thread is dispatched for execution, a table is consulted to determine whether the dispatched thread is a disruptive thread. If so, a system idle process is dispatched to the processor sharing a cache with the processor executing the disruptive thread. Since the system idle process may not use data intensively, cache thrashing may be avoided.
摘要:
Methods, systems, and products are disclosed for user defined preferred DNS routing that include mapping for a user in a data communications application a domain name of a network host to a network address for a preferred DNS server, wherein the preferred DNS server has a network address for the domain name; receiving from the user a request for access to a resource accessible through the network host; and routing to the preferred DNS server a DNS request for the network address of the network host, the DNS request including the domain name of the network host. In typical embodiments, mapping a domain name to a network address for a preferred DNS server is carried out by storing, through the data communication application, the domain name in association with the network address for a preferred DNS server in a data structure in computer memory.
摘要:
A computer implemented method, apparatus, and computer usable code for managing cache data. A partition identifier is associated with a cache entry in a cache, wherein the partition identifier identifies a last partition accessing the cache entry. The partition identifier associated with the cache entry is compared with a previous partition identifier located in a processor register in response to the cache entry being moved into a lower level cache relative to the cache. The cache entry is marked if the partition identifier associated with the cache entry matches the previous partition identifier located in the processor register to form a marked cache entry, wherein the marked cache entry is aged at a slower rate relative to an unmarked cache entry.