Fwd: [DCR] Remove devstat

[Sue Howard]

2005/6/14, Poul-Henning Kamp <phk at phk.freebsd.dk>:
> In message <1e89cd510506140433437f7b7 at mail.gmail.com>, Sue Howard writes:
> >Hi,
> >
> >I found devstat is not widely used in the device drivers. Based the
> >grep result of 'devstat_new_entry', it shows only cam, ata, fd,
> >geom_disk are using it. In my workstation, the output of 'sysctl
> >kern.devstat' shows:
>
> >I am wondering if devstat can be replaced by the sysctl nodes %desc,
> >%pnpinfo etc that jhb introduced. Almost all the information devstat
> >can provide can be also exposed by such sysctl node.
>
> Uhm, are we confused here ?
>
> Devstat is what is used for collecting transaction statistics for
> disks and scsi general devices in general.
>
> Programs like iostat and gstat uses it.
>
> The old access path (iostat) uses sysctls, but the new and practically
> overhead free access path is mmap(2) which gstat uses.

I am confused because, in the devstat.h file, it defines an enum
devstat_type_flags that I am interested in. This enum defines the
devices type(catalog). I think this type should be a general property
of a device driver. So I think devstat is a general framework to
collect all types of the information related to a device.

Anyway, since devicestat is only used for collect statistics, I'd like
to remove the this type from the devstat. And we can implement this
type into devclass(device_t?? maybe). This is what I proposed. It will
bring some benifits like remove the long regex to match NIC interface
in devd.conf, etc.

Howard