Commit Graph

11 Commits

Author SHA1 Message Date
Andriy Gapon
b064b6d1cd dtrace_gethrtime: improve scaling of TSC ticks to nanoseconds
Currently dtrace_gethrtime uses formula similar to the following for
converting TSC ticks to nanoseconds:
rdtsc() * 10^9 / tsc_freq
The dividend overflows 64-bit type and wraps-around every 2^64/10^9 =
18446744073 ticks which is just a few seconds on modern machines.

Now we instead use precalculated scaling factor of
10^9*2^N/tsc_freq < 2^32 and perform TSC value multiplication separately
for each 32-bit half.  This allows to avoid overflow of the dividend
described above.
The idea is taken from OpenSolaris.
This has an added feature of always scaling TSC with invariant value
regardless of TSC frequency changes. Thus the timestamps will not be
accurate if TSC actually changes, but they are always proportional to
TSC ticks and thus monotonic. This should be much better than current
formula which produces wildly different non-monotonic results on when
tsc_freq changes.

Also drop write-only 'cp' variable from amd64 dtrace_gethrtime_init()
to make it identical to the i386 twin.

PR:		kern/127441
Tested by:	Thomas Backman <serenity@exscape.org>
Reviewed by:	jhb
Discussed with:	current@, bde, gnn
Silence from:	jb
Approved by:	re (gnn)
MFC after:	1 week
2009-07-15 17:07:39 +00:00
Andriy Gapon
f340e9fe71 dtrace/amd64: fix virtual address checks
On amd64 KERNBASE/kernbase does not mean start of kernel memory.
This should fix a KASSERT panic in dtrace_copycheck when copyin*()
is used in D program.
Also make checks for user memory a bit stricter.

Reported by:	Thomas Backman <serenity@exscape.org>
Submitted by:	wxs (kaddr part)
Tested by:	Thomas Backman (prototype), wxs
Reviewed by:	alc (concept), jhb, current@
Aprroved by:	jb (concept)
MFC after:	2 weeks
PR:		kern/134408
2009-06-24 16:03:57 +00:00
Stacey Son
a5aedd68b4 Add the OpenSolaris dtrace lockstat provider. The lockstat provider
adds probes for mutexes, reader/writer and shared/exclusive locks to
gather contention statistics and other locking information for
dtrace scripts, the lockstat(1M) command and other potential
consumers.

Reviewed by:	attilio jhb jb
Approved by:	gnn (mentor)
2009-05-26 20:28:22 +00:00
Robert Watson
455f3aa24f Move dtnfsclient.c in the cddl tree to nfs_kdtrace.c in the nfsclient
directory, since it's under a BSD license, and this keeps NFS internals-
aware tracing parts close to NFS.

MFC after:	1 month
Suggested by:	jhb
2009-03-25 17:47:22 +00:00
Robert Watson
10263f0832 Add DTrace probes to the NFS access and attribute caches. Access cache
events are:

  nfsclient:accesscache:flush:done
  nfsclient:accesscache:get:hit
  nfsclient:accesscache:get:miss
  nfsclient:accesscache:load:done

They pass the vnode, uid, and requested or loaded access mode (if any);
the load event may also report a load error if the RPC fails.

The attribute cache events are:

  nfsclient:attrcache:flush:done
  nfsclient:attrcache:get:hit
  nfsclient:attrcache:get:miss
  nfsclient:attrcache:load:done

They pass the vnode, optionally the vattr if one is present (hit or load),
and in the case of a load event, also a possible RPC error.

MFC after:	1 month
Sponsored by:	Google, Inc.
2009-03-24 17:14:34 +00:00
Robert Watson
47294818f9 Add dtnfsclient, a first cut at an NFSv2/v3 client reuest DTrace
provider.  The NFS client exposes 'start' and 'done' probes for NFSv2
and NFSv3 RPCs when using the new RPC implementation, passing in the
vnode, mbuf chain, credential, and NFSv2 or NFSv3 procedure number.
For 'done' probes, the error number is also available.

Probes are named in the following way:

  ...
  nfsclient:nfs2:write:start
  nfsclient:nfs2:write:done
  ...
  nfsclient:nfs3:access:start
  nfsclient:nfs3:access:done
  ...

Access to the unmarshalled arguments is not easily available at this
point in the stack, but the passed probe arguments are sufficient to
to a lot of interesting things in practice.  Technically, these probes
may cover multiple RPC retransmits, and even transactions if the
transaction ID change as a result of authentication failure or a
jukebox error from the server, but usefully capture the intent of a
single NFS request, such as access, getattr, write, etc.

Typical use might involve profiling RPC latency by system call, number
of RPCs, how often a getattr leads to a call to access, when failed
access control checks occur, etc.  More detailed RPC information might
best be provided by adding a krpc provider.  It would also be useful
to add NFS client probes for events such as the access cache or
attribute cache satisfying requests without an RPC.

Sponsored by:	Google, Inc.
MFC after:	1 month
2009-03-22 22:07:52 +00:00
Ganbold Tsagaankhuu
79dae0aa0b Remove unused variable.
Found with:     Coverity Prevent(tm)
CID: 3669,3671

Approved by: jb
2008-11-25 19:25:54 +00:00
Craig Rodrigues
f5a97d1bcb Merge latest DTrace changes from Perforce. 2008-11-05 19:39:11 +00:00
Ed Schouten
d3ce832719 Remove unit2minor() use from kernel code.
When I changed kern_conf.c three months ago I made device unit numbers
equal to (unneeded) device minor numbers. We used to require
bitshifting, because there were eight bits in the middle that were
reserved for a device major number. Not very long after I turned
dev2unit(), minor(), unit2minor() and minor2unit() into macro's.
The unit2minor() and minor2unit() macro's were no-ops.

We'd better not remove these four macro's from the kernel, because there
is a lot of (external) code that may still depend on them. For now it's
harmless to remove all invocations of unit2minor() and minor2unit().

Reviewed by:	kib
2008-09-26 14:19:52 +00:00
John Birrell
5a3c3bfaa3 The cyclic timer device. This is a cut down version of the one in
OpenSolaris. We don't have the lock levels that they do, so this is just
hooked into clock interrupts.
2008-05-23 22:21:58 +00:00
John Birrell
91eaf3e183 Custom DTrace kernel module files plus FreeBSD-specific DTrace providers. 2008-05-23 05:59:42 +00:00