loic@axis.fr (Loic Dachary) (08/05/88)
I'm using sar extensivly for two purposes :
- Writing a course chapter on Un*x tunning and tools to watch
system activity (sar, sag, sadp)
- Try to prove that GNU-emacs is not overloading our V*X-750 running
N*XI V.2 (hopeless ?)
The lack of documentation is partialy compensed by M.J.BACH famous book
and the AT&T 386/V.3 Administrator Guide.
But some points are still missing :
sar -d : . Is there any ceil values for these data ? Specially
%busy, r+w/s, avwait. I know for example that runq-sz
should not be greater than 2, and %rcache lower than 90%.
. Can blk/s be recalculated (approximately) with other values ?
I tried to sum bread and bwrite without great success
(bread + bwrite <= blks/s / 2, could that mean bread is
1024 byte blocks and blks/s 512 byte blocks ?)
sar -q : . swpq-sz and swpocc have no values most of the time. But
when the system is heavy loaded some values like 1.2 and 10%
appear. I guess this is swapping ;-). But what hell does that
mean in a paged system ?
sar -p : . The most stupid question due to my ignorance : what is a
reclaimed page ? (rclm/s).
Finally I'm interested in any idea or pointer about
. Typical methods of diagnostics using sar.
. Useful data mixin using sag (-y 'runq-sz 0 8 ; freemem 50 3000' for
instance and specially some using -x 'everything but time')
. Public domain system activity tools
Thank you, all.loic@axis.fr (Loic Dachary) (08/05/88)
I'm using sar extensively for two purposes :
- Writing a course chapter on Un*x tunning and tools to watch
system activity (sar, sag, sadp)
- Try to prove that GNU-emacs is not overloading our V*X-750 running
N*XI V.2 (hopeless ?)
The lack of documentation is partially compensed by M.J.BACH famous book
and the AT&T 386/V.3 Administrator Guide.
But some points are still missing :
sar -d : . Is there any ceil values for these data ? Specially
%busy, r+w/s, avwait. I know for example that runq-sz
should not be greater than 2, and %rcache lower than 90%.
. Can blk/s be recalculated (approximately) with other values ?
I tried to sum bread and bwrite without great success
(bread + bwrite <= blks/s / 2, could that mean bread is
1024 byte blocks and blks/s 512 byte blocks ?)
sar -q : . swpq-sz and swpocc have no values most of the time. But
when the system is heavy loaded some values like 1.2 and 10%
appear. I guess this is swapping ;-). But what hell does that
mean in a paged system ?
sar -p : . The most stupid question due to my ignorance : what is a
reclaimed page ? (rclm/s).
Finally I'm interested in any idea or pointer about
. Typical methods of diagnostics using sar.
. Useful data mixin using sag (-y 'runq-sz 0 8 ; freemem 50 3000' for
instance and specially some using -x 'everything but time')
. Public domain system activity tools
Thank you, all.
Loic Dachary tel : 46 03 37 75
Axis Digital email: loic@axis.fr ...!mcvax!inria!coms!axis!loic
135 Rue d'Aguesseau
92100 Boulogne, France
"GNU-emacs not yet standalone"dwc@homxc.UUCP (Malaclypse the Elder) (08/10/88)
In article <446@axis.fr>, loic@axis.fr (Loic Dachary) writes: > > > sar -d : . Is there any ceil values for these data ? Specially > %busy, r+w/s, avwait. I know for example that runq-sz > should not be greater than 2, and %rcache lower than 90%. > . Can blk/s be recalculated (approximately) with other values ? > I tried to sum bread and bwrite without great success > (bread + bwrite <= blks/s / 2, could that mean bread is > 1024 byte blocks and blks/s 512 byte blocks ?) you have to also add in the i/o from swapping and/or page stealing. and a ceil for %busy is 100% :-) the r+w/s is determined by the rate at which the disk can do i/os. avwait has no ceiling as anyone who has worked on a busy system knows. > sar -q : . swpq-sz and swpocc have no values most of the time. But > when the system is heavy loaded some values like 1.2 and 10% > appear. I guess this is swapping ;-). But what hell does that > mean in a paged system ? in a paged system, you still try to do process swaps to reduce memory contention between processes. so this is still a measure of the amount of memory contention. > sar -p : . The most stupid question due to my ignorance : what is a > reclaimed page ? (rclm/s). yeah, i have complaints about the name. i can't remember if it means pages reclaimed for the system (e.g. page steals) or whether it means pages that are reclaimed by the page fault handler (e.g. finding it in the page cache). well, i just looked and it means the number of pages that have been freed thru the kernel memfree() routine. this can result from page steals but can also result from process swaps, exits and other events in which the system can reclaim memory. > Finally I'm interested in any idea or pointer about > > . Typical methods of diagnostics using sar. try looking for a reference to 'TUNEX' in one of the USENIX proceedings a couple of years ago. its an expert system applied to the tuning of unix systems for performance (pre-paging though...i think that behrohk samadi, the TUNEX developer, has some plans to do a version for paging). danny chen att!homxc!dwc