multiple issues with devstat_*(9)
Alexander Best
arundel at freebsd.org
Mon Apr 11 16:51:34 UTC 2011
On Mon Apr 11 11, Kenneth D. Merry wrote:
> On Sun, Apr 10, 2011 at 23:19:31 +0300, Alexander Motin wrote:
> > Alexander Best wrote:
> > > On Thu Apr 7 11, Alexander Motin wrote:
> > >> Alexander Best wrote:
> > >>> On Fri Apr 1 11, John Baldwin wrote:
> > >>>> On Thursday, March 31, 2011 6:33:39 pm Alexander Best wrote:
> > >>>>> i think there are multiple issues with devstat. i found the following in
> > >>>>> devicestat.h:
> > >> ...
> > >>
> > >>>>> funny thing is i found the following in scsi_pass.c:
> > >>>>>
> > >>>>> softc->device_stats = devstat_new_entry("pass",
> > >>>>> periph->unit_number, 0,
> > >>>>> DEVSTAT_NO_BLOCKSIZE
> > >>>>> | (no_tags ? DEVSTAT_NO_ORDERED_TAGS : 0),
> > >>>>> softc->pd_type |
> > >>>>> DEVSTAT_TYPE_IF_SCSI |
> > >>>>> DEVSTAT_TYPE_PASS,
> > >>>>> DEVSTAT_PRIORITY_PASS);
> > >>>>>
> > >>>>> ...so pass* *should* show up under iostat -t scsi.
> > >> As I can see, this is a bug (or feature) of the libdevstat /
> > >> devstat_selectdevs(). If you specify any -t, then pass devices will be
> > >> reported only if you request "pass" specifically.
> > >>
> > >>>> Hmm, pass devices for adaX should not be SCSI though, they should be ide I
> > >>>> think.
> > >>> i think the situation with ATA_CAM should be discussed further. still besides
> > >>> this issue there are many more with devstat(3).
> > >>>
> > >>> i'll try to track all the "devstat_new_entry()" occurrences and see if some
> > >>> issues can be fixed. maybe only the proper DEVSTAT_* args were forgotten.
> > >> Assuming that SCSI and IDE in -t option means transport type, and
> > >> assuming that we count everything except ATA and SATA as SCSI, I've made
> > >> following patch, that should fix issues from the CAM side:
> > >> http://people.freebsd.org/~mav/cam.devstat.patch
> > >
> > > with your patch i get the following output:
> > >
> > > otaku% iostat -t ide
> > > tty ada0 ada1 cpu
> > > tin tout KB/t tps MB/s KB/t tps MB/s us ni sy in id
> > > 6 144 14.21 6 0.09 20.46 40 0.81 2 0 3 0 95
> > > otaku% iostat -t scsi
> > > tty cd0 cpu
> > > tin tout KB/t tps MB/s us ni sy in id
> > > 6 146 2.32 0 0.00 2 0 3 0 95
> > > otaku% iostat -t pass
> > > tty pass0 pass1 pass2 cpu
> > > tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
> > > 6 147 0.36 0 0.00 0.36 0 0.00 0.00 0 0.00 2 0 3 0 95
> > > otaku% iostat -t da
> > > tty ada0 ada1 cpu
> > > tin tout KB/t tps MB/s KB/t tps MB/s us ni sy in id
> > > 6 147 14.21 6 0.08 20.46 37 0.75 1 0 3 0 95
> > > otaku% iostat -t cd
> > > tty cd0 cpu
> > > tin tout KB/t tps MB/s us ni sy in id
> > > 7 147 2.32 0 0.00 1 0 3 0 95
> > > otaku% iostat -t other
> > > tty cpu
> > > tin tout us ni sy in id
> > > 7 149 1 0 3 0 95
> > > otaku% iostat -n 100
> > > tty ada0 ada1 cd0 pass0 pass1 pass2 cpu
> > > tin tout KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s us ni sy in id
> > > 6 135 14.21 5 0.07 20.44 32 0.64 2.32 0 0.00 0.36 0 0.00 0.36 0 0.00 0.00 0 0.00 1 0 3 0 96
> > >
> > > the the remaining issues imho are:
> > >
> > > 1) ada* and cd* are SATA/ATA devices. so i think they should show up together
> > > either under ide *or* scsi. i don't have any *real* scsi devices.
> >
> > I've just retested the patch and haven't reproduced your problem:
> > %iostat -d
> > da0 ada0 da1 cd0
> > KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s
> > 0.01 0 0.00 3.27 1 0.00 2.65 1 0.00 0.00 0 0.00
> > %iostat -d -t ide
> > da0 ada0 cd0
> > KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s
> > 0.01 0 0.00 3.27 1 0.00 0.00 0 0.00
> > %iostat -d -t scsi
> > da1
> > KB/t tps MB/s
> > 2.65 1 0.00
> > %iostat -d -t pass
> > pass0 pass1 pass2 pass3
> > KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s
> > 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00
> > %iostat -d -t ide,pass
> > pass0 pass1 pass2
> > KB/t tps MB/s KB/t tps MB/s KB/t tps MB/s
> > 0.00 0 0.00 0.00 0 0.00 0.00 0 0.00
> > %iostat -d -t scsi,pass
> > pass3
> > KB/t tps MB/s
> > 0.00 0 0.00
> >
> > da0 is an PATA ATAPI ZIP, da1 - USB floppy, ada0 - SATA HDD, cd0 - PATA
> > ATAPI CD-ROM.
> >
> > Just an idea, aren't you are using legacy ata(4) + atapicam for your
> > cd0? atapicam lies that it's buses are SPI (SCSI).
> >
> > > 2) the pass* devices still don't show up under ide/scsi/other. that's ok, but
> > > then the src comments and manual pages need to be changed accordingly.
> >
> > As I have told - it is a bug/feature of libdevstat. It should not be
> > difficult to fix, if it is really a bug.
>
> That was intentional, if I can remember what I intended in 1997/1998.
>
> The reason was that since there is one passthrough device created for every
> device that CAM manages, you don't want to show pass(4) devices when the
> user says 'iostat -t scsi'. Otherwise he might get all pass(4) devices,
> depending on the order of devices in the system.
i understand. however i think then we are being faced with a few doc bugs.
have a look at this passage from devstat(9) e.g.:
" Each device is given a device type. Pass-through devices have the same
underlying device type and interface as the device they provide an inter-
face for, but they also have the pass-through flag set. The base device
types are identical to the SCSI device type numbers, so with SCSI periph-
erals, the device type returned from an inquiry is usually ORed with the
SCSI interface type and the pass-through flag if appropriate. The device
type flags are as follows:"
...i also found some comments in the source mentioning the above behavior.
cheers.
alex
>
> But, if it's pass(4) devices you want, you can ask for them specifically,
> or for all SCSI/IDE pass(4) devices, as mav did above.
>
> Ken
> --
> Kenneth Merry
> ken at FreeBSD.ORG
--
a13x
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