s are described as follows:
-
address translation faults
-
Incremented for each occurrence of an address translation page fault. I/O may or may not be required to resolve the page fault. Storage protection page faults (lock misses) are not included in this count.
-
page ins
-
Incremented for each page read in by the virtual memory manager. The count is incremented for page ins from page space and file space. Along with the page out statistic, this represents the total amount of real I/O initiated by the virtual memory manager.
-
page outs
-
Incremented for each page written out by the virtual memory manager. The count is incremented for page outs to page space and for page outs to file space. Along with the page in statistic, this represents the total amount of real I/O initiated by the virtual memory manager.
-
paging space page ins
-
Incremented for VMM initiated page ins from paging space only.
-
paging space page outs
-
Incremented for VMM initiated page outs to paging space only.
-
total reclaims
-
Incremented when an address translation fault can be satisfied without initiating a new I/O request. This can occur if the page has been previously requested by VMM, but the I/O has not yet completed; or if the page was pre-fetched by VMM's read-ahead algorithm, but was hidden from the faulting segment; or if the page has been put on the free list and has not yet been reused.
-
zero-filled page faults
-
Incremented if the page fault is to working storage and can be satisfied by assigning a frame and zero-filling it.
-
executable-filled page faults
-
Incremented for each instruction page fault.
-
pages examined by the clock
-
VMM uses a clock-algorithm to implement a pseudo least recently used (lru) page replacement scheme. Pages are
aged by being examined by the clock. This count is incremented for each page examined by the clock.
-
revolutions of the clock hand
-
Incremented for each VMM clock revolution (that is, after each complete scan of memory).
-
pages freed by the clock
-
Incremented for each page the clock algorithm selects to free from real memory.
|
| |
-
backtracks
-
Incremented for each page fault that occurs while resolving a previous page fault. (The new page fault must be resolved first and then initial page faults can be
backtracked.)
-
free frame waits
-
Incremented each time a process requests a page frame, the free list is empty, and the process is forced to wait while the free list is replenished.
-
extend XPT waits
-
Incremented each time a process is waited by VMM due to a commit in progress for the segment being accessed.
-
pending I/O waits
-
Incremented each time a process is waited by VMM for a page-in I/O to complete.
-
start I/Os
-
Incremented for each read or write I/O request initiated by VMM.
-
iodones
-
Incremented at the completion of each VMM I/O request.
-
CPU context switches
-
Incremented for each processor context switch (dispatch of a new process).
-
device interrupts
-
Incremented on each hardware interrupt.
-
software interrupts
-
Incremented on each software interrupt. A software interrupt is a machine instruction similar to a hardware interrupt that saves some state and branches to a service routine. System calls are implemented with software interrupt instructions that branch to the system call handler routine.
-
decrementer interrupts
-
Incremented on each decrementer interrupt.
-
mpc send interrupts
-
Incremented on each mpc send interrupt
-
mpc receive interrupts
-
Incremented on each mpc receive inte
|