Date: Thu, 13 Oct 2005 14:12:11 +0200 From: Max Laier <max@love2party.net> To: freebsd-current@freebsd.org Cc: Eric Anderson <anderson@centtech.com> Subject: Re: ufsstat - testers / feedback wanted! Message-ID: <200510131412.23525.max@love2party.net> In-Reply-To: <434E46C0.7060903@centtech.com> References: <434E46C0.7060903@centtech.com>
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On Thursday 13 October 2005 13:36, Eric Anderson wrote:
> [resend to -current for broader test audience]
>
> I've just finished the first version of ufsstat, a tool to show local
> filesystem statistics much like nfsstat does for NFS. The patch and
> tool is against 6.0, but it will probably apply and work fine under
> -CURRENT and possibly 5.x as well.
>
> I'm looking for bug reports, comments/suggestions on style(9), and
> anything else, since this is my first C project, and of course first
> real FreeBSD contribution. :)
The patch contains some jitter in the first three or four files due to olde=
r=20
versions in src-patched. As all the statistic gathering is #ifdef'ed it=20
should not hurt performance in the disabled case. It will look nicer if yo=
u=20
define a macro to update statistics like:
#ifdef UFS_STATS
#define UFS_STATS_UPDATE(field) ufsstats.field++
#else
#define UFS_STATS_UPDATE(field)
#end
This will in turn only use one line per update point and you don't have to =
do=20
the ugly:
#ifdef UFS_STATS
ufsstats.fsync++;
#endif
Also, make sure to declare "extern struct ufsstats ufsstats" in ufsstats.h=
=20
under _KERNEL and define it in just one place. As is, you don't record the=
=20
updates from ffs_vnops.c into the right structure. Finally, you should=20
consider 64 bit counter for some, if not all, fields as they will overflow=
=20
quickly.
> To use it, do this:
> cd /tmp
> fetch http://www.googlebit.com/software/ufsstat/ufsstat-20051011.tar.gz
> cd /usr
> tar xvzf /tmp/ufsstat-20051011.tar.gz
> patch <./ufsstats.patch
>
> add:
> OPTIONS UFS_STAT
> to your kernel.
>
> Rebuild and install world/kernel.
>
> Now, you can use ufsstat to show you statistics from your local
> filesystems, like this:
>
> # ufsstat
> Create Remove Link Symlink Mkdir Rmdir Rename
> 289048 794043 4361 12558 25796 117739 0
> GetAttr SetAttr Open Close ReadDir ReadLink VInit
> 64868230 759824 10701553 9891642 5042948 0 45315645
> Chmod Chown Whiteout Strategy Access Mknod NewInode
> 409782 79612 0 4020035 0 3 0
> Fsync SyncVnode LockVnode RdVnode WrVNode
> 0 0 0 0 0
> ExtRead Extwrite FndExtAtt RdExtAttr OpnExtAtt ClseExtAt ExtStrtgy
> 0 0 0 0 0 0 0
>
> or watch over time with the -w switch.
>
> I have not done any performance testing yet to see if it impacts
> filesystem performance by any measurable amount, so if someone does do
> this testing before I do, please post your results!
I don't think you can measure one single interger (or 64bit) increase in fa=
ce=20
of a operation that has to access backing store. Even if there is a=20
performance hit, you don't have to build your kernel with the option enable=
d.
It might be (more) interesting to have these stats on a per-mountpoint basi=
s. =20
Not sure if you have enough state available to record all of the above, but=
=20
since you asked for input - this might be worth investigating.
=2D-=20
/"\ Best regards, | mlaier@freebsd.org
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