The existing implementations of POSIX tsearch() and tdelete() don't
attempt to perform any balancing at all. Testing reveals that inserting
100k nodes into a tree sequentially takes approximately one minute on my
system.
Though most other BSDs also don't use any balanced tree internally, C
libraries like glibc and musl do provide better implementations. glibc
uses a red-black tree and musl uses an AVL tree.
Red-black trees have the advantage over AVL trees that they only require
O(1) rotations after insertion and deletion, but have the disadvantage
that the tree has a maximum depth of 2*log2(n) instead of 1.44*log2(n).
My take is that it's better to focus on having a lower maximum depth,
for the reason that in the case of tsearch() the invocation of the
comparator likely dominates the running time.
This change replaces the tsearch() and tdelete() functions by versions
that create an AVL tree. Compared to musl's implementation, this version
is different in two different ways:
- We don't keep track of heights; just balances. This is sufficient.
This has the advantage that it reduces the number of nodes that are
being accessed. Storing heights requires us to also access all of the
siblings along the path.
- Don't use any recursion at all. We know that the tree cannot 2^64
elements in size, so the height of the tree can never be larger than
96. Use a 128-bit bitmask to keep track of the path that is computed.
This allows us to iterate over the same path twice, meaning we can
apply rotations from top to bottom.
Inserting 100k nodes into a tree now only takes 0.015 seconds. Insertion
seems to be twice as fast as glibc, whereas deletion has about the same
performance. Unlike glibc, it uses a fixed amount of memory.
I also experimented with both recursive and iterative bottom-up
implementations of the same algorithm. This iterative top-down version
performs similar to the recursive bottom-up version in terms of speed
and code size.
For some reason, the iterative bottom-up algorithm was actually 30%
faster for deletion, but has a quadratic memory complexity to keep track
of all the parent pointers.
Reviewed by: jilles
Obtained from: https://github.com/NuxiNL/cloudlibc
Differential Revision: https://reviews.freebsd.org/D4412
In r289315, I added new fields to res_state. This broke binary
backward compatibility. It also broke some ports (and possibly
other code) by requiring the definition of time_t and struct timespec.
Fix these problems by moving the new fields into __res_state_ext.
Suggested by: ume
Reviewed by: ume
MFC after: 3 days
Sponsored by: Dell Inc.
Differential Revision: https://reviews.freebsd.org/D4472
r289315 required time_t and struct timespec to be defined before
including <resolv.h>. This broke the build of net-mgmt/sx, at least.
Include <sys/timespec.h> in resolv.h to fix this with minimal pollution.
Reported by: Raphael Kubo da Costa <rakuco>
MFC after: 3 days
Sponsored by: Dell Inc.
This avoids the need for an afterinstall: hook and a check for LIBRARIES_ONLY.
It also now respects INCLUDEDIR.
This came in r249484.
Sponsored by: EMC / Isilon Storage Division
Because of how osreldate.h was being built with newvers.sh, which always
spat out a vers.c dependent on SVN or git, the meta mode build was
considering osreldate.h to depend on the current git or SVN index. This
would lead to entire tree rebuilds when modifying git's index. There's
no reason to be generating vers.c here so just skip it.
While here, in mk-osreldate.sh rename PARAM_H to proper PARAMFILE (which
newvers.sh already has a default for) and remove unneeded export.
Sponsored by: EMC / Isilon Storage Division
The _SKIP_BUILD is used while computing DIRDEPS. If MACHINE=host is passed in
then this logic was replacing 'MACHINE' with a literal value of the host arch,
which then caused the dirdeps graph to be wrong since it no longer had the
literal 'host' for any of include's dependencies.
This is a NOP currently since include/ is not usually built with MACHINE=host.
Sponsored by: EMC / Isilon Storage Division
This allows META_FILES option to be renamed META_MODE.
Also add META_COOKIE_TOUCH for use in targets that can benefit
from a cookie when in meta mode.
Differential Revision: https://reviews.freebsd.org/D4153
Reviewed by: bdrewery
On each resolver query, use stat(2) to see if the modification time
of /etc/resolv.conf has changed. If so, reload the file and reinitialize
the resolver library. However, only call stat(2) if at least two seconds
have passed since the last call to stat(2), since calling it on every
query could kill performance.
This new behavior is enabled by default. Add a "reload-period" option
to disable it or change the period of the test.
Document this behavior and option in resolv.conf(5).
Polish the man page just enough to appease igor.
https://lists.freebsd.org/pipermail/freebsd-arch/2015-October/017342.html
Reviewed by: kp, wblock
Discussed with: jilles, imp, alfred
MFC after: 1 month
Relnotes: yes
Sponsored by: Dell Inc.
Differential Revision: https://reviews.freebsd.org/D3867
FreeBSD extended ctypes to include numbers (e.g. isnumber()) but never
actually implemented it. The isnumber() function was equivalent to the
isdigit() function in every case.
Now that DragonFly's ctype source files have number definitions, the
number ctype can finally be implemented. It's given a new flag _CTYPE_N.
The isalnum() and iswalnum() functions have been changed to use this
flag rather than the _CTYPE_D digit flag.
While isalnum(), isnumber(), and their wide equivalents now return
different values in locale cases, the ishexnumber() and iswhexnumber()
functions are unchanged. They are still aliases for isxdigit() and
iswxdigit().
Also change ctype.h for isdigit and isxdigit to use sbistype like the
other functions.
Obtained from: dragonfly
If the command to be ran changes then a rebuild is caused. Checking
exists(${DESTDIR}...) from make results in this on the 2nd and
possibly subsequent builds due to staging during build. Avoid this
by always running the existence check in the make sh command.
Sponsored by: EMC / Isilon Storage Division
- Use _Bool rather than bool to resolve missing type errors in malloc_np.h.
- Fix malloc manual page #include documentation.
- Add *allocm manual pages to obsolete files.
Submitted by: jbeich
Start using the gcc sentinel attribute, which can be used to
mark varargs function that need a NULL pointer to mark argument
termination, like execl(3).
Relnotes: yes
This function is equivalent to fclose(3) function except that it
does not close the underlying file descriptor.
fdclose(3) is step forward to make FILE structure private.
Reviewed by: wblock, jilles, jhb, pjd
Approved by: pjd (mentor)
Differential Revision: https://reviews.freebsd.org/D2697
Off by default, build behaves normally.
WITH_META_MODE we get auto objdir creation, the ability to
start build from anywhere in the tree.
Still need to add real targets under targets/ to build packages.
Differential Revision: D2796
Reviewed by: brooks imp
This lets the compiler know about the alignment of pointers returned
by aligned_alloc(3), posix_memalign(3). and contigmalloc(9)
Currently this is only supported in recent gcc but we are ready to
use it if clang implements it.
Relnotes: yes
Add a manpage for it, assign the copyright to the OpenBSD project on it since it
is mostly copy/paste from OpenBSD manpage.
style(9) fixes
Differential Revision: https://reviews.freebsd.org/D2420
Reviewed by: kib
discontinued by its initial authors. In FreeBSD the code was already
slightly edited during the pf(4) SMP project. It is about to be edited
more in the projects/ifnet. Moving out of contrib also allows to remove
several hacks to the make glue.
Reviewed by: net@
The `nonnull' attribute specifies that some function parameters should be
non-null pointers. This is very useful as it helps the compiler generate
warnings on suspicious code and can also enable some small optimizations.
Also start using 'alloc_size' attribute in the allocator functions.
This is an initial step to better integrate our libc with the compiler:
these attributes are fully supported by clang and they are also useful
for the static analyzer.
Note that due to some bogus internal procedure in the way gcc ports
are built they may require updating if they were built before r280801.
Relnotes: yes
Hinted by: Android's bionic libc
Differential Revision: https://reviews.freebsd.org/D2107
GCC is still carries an old version of cdefs.h which doesn't
accept multiple parameters for the nonnull attribute.
Since this issue probably affects many ports in the tree
we will revert it for now until gcc gets fixed.
The `nonnull' attribute specifies that some function parameters should be
non-null pointers. This is very useful as it helps the compiler generate
warnings on suspicious code and can also enable some small optimizations.
In clang this is also useful for the static analyzer.
While we could go on defining this all over the tree, it only
makes sense to annotate a subset of critical functions.
Hinted by: Android's bionic libc
Differential Revision: https://reviews.freebsd.org/D2101
