summaryrefslogtreecommitdiffstats
path: root/ChangeLog
diff options
context:
space:
mode:
authorJason Evans <je@fb.com>2015-02-24 06:28:43 (GMT)
committerJason Evans <je@fb.com>2015-03-09 23:02:40 (GMT)
commit54673fd8d719e081536fb531417cd9060de895f0 (patch)
treeef273885fdd89946e6843a459a4b9e31071040c1 /ChangeLog
parent04ca7580dbc409915de05cb1cee12a369e898590 (diff)
downloadjemalloc-54673fd8d719e081536fb531417cd9060de895f0.zip
jemalloc-54673fd8d719e081536fb531417cd9060de895f0.tar.gz
jemalloc-54673fd8d719e081536fb531417cd9060de895f0.tar.bz2
Update ChangeLog.
Diffstat (limited to 'ChangeLog')
-rw-r--r--ChangeLog151
1 files changed, 150 insertions, 1 deletions
diff --git a/ChangeLog b/ChangeLog
index d56ee99..ef7dbfd 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -5,6 +5,155 @@ found in the git revision history:
https://github.com/jemalloc/jemalloc
+* 4.0.0 (XXX) See https://github.com/jemalloc/jemalloc/milestones/4.0.0 for
+ remaining work.
+
+ This version contains many speed and space optimizations, both minor and
+ major. The major themes are generalization, unification, and simplification.
+ Although many of these optimizations cause no visible behavior change, their
+ cumulative effect is substantial.
+
+ New features:
+ - Normalize size class spacing to be consistent across the complete size
+ range. By default there are four size classes per size doubling, but this
+ is now configurable via the --with-lg-size-class-group option. Also add the
+ --with-lg-page, --with-lg-page-sizes, --with-lg-quantum, and
+ --with-lg-tiny-min options, which can be used to tweak page and size class
+ settings. Impacts:
+ + Worst case performance for incrementally growing/shrinking reallocation
+ is improved because there are far fewer size classes, and therefore
+ copying happens less often.
+ + Internal fragmentation is limited to 20% for all but the smallest size
+ classes (those less than four times the quantum). (1B + 4 KiB)
+ and (1B + 4 MiB) previously suffered nearly 50% internal fragmentation.
+ + Chunk fragmentation tends to be lower because there are fewer distinct run
+ sizes to pack.
+ - Add support for explicit tcaches. The "tcache.create", "tcache.flush", and
+ "tcache.destroy" mallctls control tcache lifetime and flushing, and the
+ MALLOCX_TCACHE(tc) and MALLOCX_TCACHE_NONE flags to the *allocx() API
+ control which tcache is used for each operation.
+ - Implement per thread heap profiling, as well as the ability to
+ enable/disable heap profiling on a per thread basis. Add the "prof.reset",
+ "prof.lg_sample", "thread.prof.name", "thread.prof.active",
+ "opt.prof_thread_active_init", "prof.thread_active_init", and
+ "thread.prof.active" mallctls.
+ - Add support for per arena application-specified chunk allocators, configured
+ via the "arena<i>.chunk.alloc" and "arena<i>.chunk.dalloc" mallctls.
+ - Refactor huge allocation to be managed by arenas, so that arenas now
+ function as general purpose independent allocators. This is important in
+ the context of user-specified chunk allocators, aside from the scalability
+ benefits. Related new statistics:
+ + The "stats.arenas.<i>.huge.allocated", "stats.arenas.<i>.huge.nmalloc",
+ "stats.arenas.<i>.huge.ndalloc", and "stats.arenas.<i>.huge.nrequests"
+ mallctls provide high level per arena huge allocation statistics.
+ + The "arenas.nhchunks", "arenas.hchunks.<i>.size",
+ "stats.arenas.<i>.hchunks.<j>.nmalloc",
+ "stats.arenas.<i>.hchunks.<j>.ndalloc",
+ "stats.arenas.<i>.hchunks.<j>.nrequests", and
+ "stats.arenas.<i>.hchunks.<j>.curhchunks" mallctls provide per size class
+ statistics.
+ - Add the 'util' column to malloc_stats_print() output, which reports the
+ proportion of available regions that are currently in use for each small
+ size class.
+ - Add "alloc" and "free" modes for for junk filling (see the "opt.junk"
+ mallctl), so that it is possible to separately enable junk filling for
+ allocation versus deallocation.
+ - Add the jemalloc-config script, which provides information about how
+ jemalloc was configured, and how to integrate it into application builds.
+ - Add metadata statistics, which are accessible via the "stats.metadata",
+ "stats.arenas.<i>.metadata.mapped", and
+ "stats.arenas.<i>.metadata.allocated" mallctls.
+ - Add the "prof.gdump" mallctl, which makes it possible to toggle the gdump
+ feature on/off during program execution.
+ - Add sdallocx(), which implements sized deallocation. The primary
+ optimization over dallocx() is the removal of a metadata read, which often
+ suffers an L1 cache miss.
+ - Add missing header includes in jemalloc/jemalloc.h, so that applications
+ only have to #include <jemalloc/jemalloc.h>.
+ - Add support for additional platforms:
+ + Bitrig
+ + Cygwin
+ + DragonFlyBSD
+ + iOS
+ + OpenBSD
+ + OpenRISC/or1k
+
+ Optimizations:
+ - Switch run and chunk allocation from first-best-fit (among best-fit
+ candidates, choose the lowest in memory) to first-fit (among all candidates,
+ choose the lowest in memory). This tends to reduce chunk and virtual memory
+ fragmentation, respectively.
+ - Maintain dirty runs in per arena LRUs rather than in per arena trees of
+ dirty-run-containing chunks. In practice this change significantly reduces
+ dirty page purging volume.
+ - Integrate whole chunks into the unused dirty page purging machinery. This
+ reduces the cost of repeated huge allocation/deallocation, because it
+ effectively introduces a cache of chunks.
+ - Split the arena chunk map into two separate arrays, in order to increase
+ cache locality for the frequently accessed bits.
+ - Move small run metadata out of runs, into arena chunk headers. This reduces
+ run fragmentation, smaller runs reduce external fragmentation for small size
+ classes, and packed (less uniformly aligned) metadata layout improves CPU
+ cache set distribution.
+ - Micro-optimize the fast paths for the public API functions.
+ - Refactor thread-specific data to reside in a single structure. This assures
+ that only a single TLS read is necessary per call into the public API.
+ - Implement in-place huge allocation growing and shrinking.
+ - Refactor rtree (radix tree for chunk lookups) to be lock-free, and make
+ additional optimizations that reduce maximum lookup depth to one or two
+ levels. This resolves what was a concurrency bottleneck for per arena huge
+ allocation, because a global data structure is critical for determining
+ which arenas own which huge allocations.
+
+ Incompatible changes:
+ - Replace --enable-cc-silence with --disable-cc-silence to suppress spurious
+ warnings by default.
+ - Assure that the constness of malloc_usable_size()'s return type matches that
+ of the system implementation.
+ - Change the heap profile dump format to support per thread heap profiling,
+ and enhance pprof with the --thread=<n> option. As a result, the bundled
+ pprof must now be used rather than the upstream (gperftools) pprof.
+ - Disable "opt.prof_final" by default, in order to avoid atexit(3), which can
+ internally deadlock on some platforms.
+ - Change the "arenas.nlruns" mallctl type from size_t to unsigned.
+ - Replace the "stats.arenas.<i>.bins.<j>.allocated" mallctl with
+ "stats.arenas.<i>.bins.<j>.curregs".
+ - Ignore MALLOC_CONF in set{uid,gid,cap} binaries.
+ - Ignore MALLOCX_ARENA(a) in dallocx(), in favor of using the
+ MALLOCX_TCACHE(tc) and MALLOCX_TCACHE_NONE flags to control tcache usage.
+
+ Removed features:
+ - Remove the *allocm() API, which is superseded by the *allocx() API.
+ - Remove the --enable-dss options, and make dss non-optional on all platforms
+ which support sbrk(2).
+ - Remove the "arenas.purge" mallctl, which was obsoleted by the
+ "arena.<i>.purge" mallctl in 3.1.0.
+ - Remove the unnecessary "opt.valgrind" mallctl; jemalloc automatically
+ detects whether it is running inside Valgrind.
+ - Remove the "stats.huge.allocated", "stats.huge.nmalloc", and
+ "stats.huge.ndalloc" mallctls.
+ - Remove the --enable-mremap option.
+ - Remove the --enable-ivsalloc option, and merge its functionality into
+ --enable-debug.
+ - Remove the "stats.chunks.current", "stats.chunks.total", and
+ "stats.chunks.high" mallctls.
+
+ Bug fixes:
+ - Fix the cactive statistic to decrease (rather than increase) when active
+ memory decreases. This regression was first released in 3.5.0.
+ - Fix OOM handling in memalign() and valloc(). A variant of this bug existed
+ in all releases since 2.0.0, which introduced these functions.
+ - Fix the "arena.<i>.dss" mallctl to return an error if "primary" or
+ "secondary" precedence is specified, but sbrk(2) is not supported.
+ - Fix fallback lg_floor() implementations to handle extremely large inputs.
+ - Ensure the default purgeable zone is after the default zone on OS X.
+ - Fix latent bugs in atomic_*().
+ - Fix the "arena.<i>.dss" mallctl to handle read-only calls.
+ - Fix tls_model configuration to enable the initial-exec model when possible.
+ - Mark malloc_conf as a weak symbol so that the application can override it.
+ - Correctly detect glibc's adaptive pthread mutexes.
+ - Fix the --without-export configure option.
+
* 3.6.0 (March 31, 2014)
This version contains a critical bug fix for a regression present in 3.5.0 and
@@ -21,7 +170,7 @@ found in the git revision history:
backtracing to be reliable.
- Use dss allocation precedence for huge allocations as well as small/large
allocations.
- - Fix test assertion failure message formatting. This bug did not manifect on
+ - Fix test assertion failure message formatting. This bug did not manifest on
x86_64 systems because of implementation subtleties in va_list.
- Fix inconsequential test failures for hash and SFMT code.