$ git log --pretty=format:'%h %s (%cs)%d' v2.2.0 --
e3d506d mwrap 2.2.0 (2022-08-22)
(tag: v2.2.0)
61f9d94 various doc updates (2022-08-22)
0f18807 quiet uninitialized and unused variable warnings (2022-08-22)
aa82056 disable HeapPageBody count test for Ruby 3.1 (2022-08-22)
7ec73b9 support Ruby 3.0.x (2022-08-22)
a90e237 constify arg for totals_add_rcu (2022-08-22)
32c9a81 workaround breakage from urcu v0.11.4 (2022-08-22)
4a90540 memalign: perform rcu_read_unlock on ENOMEM (2022-08-09)
5120b83 mwrap 2.1.0 - heap_page_body struct tracking (2018-08-11)
(tag: v2.1.0)
f2155ac doc: 2.1 pre-release updates (2018-08-11)
...
$ git cat-file blob v2.2.0:README
= mwrap - LD_PRELOAD malloc wrapper + line stats for Ruby
mwrap is designed to answer the question:
Which lines of Ruby are hitting malloc the most?
mwrap wraps all malloc-family calls to trace the Ruby source
location of such calls and bytes allocated at each callsite.
As of mwrap 2.0.0, it can also function as a leak detector
and show live allocations at every call site. Depending on
your application and workload, the overhead is roughly a 50%
increase memory and runtime.
It works best for allocations under GVL, but tries to track
numeric caller addresses for allocations made without GVL so you
can get an idea of how much memory usage certain extensions and
native libraries use.
It requires the concurrent lock-free hash table from the
Userspace RCU project: https://liburcu.org/
It does not require recompiling or rebuilding Ruby, but only
supports Ruby trunk (2.6.0dev+) on a few platforms:
* GNU/Linux
* FreeBSD (tested 11.1)
It may work on NetBSD, OpenBSD and DragonFly BSD.
== Install
# FreeBSD: pkg install liburcu
# Debian-based systems: apt-get liburcu-dev
# Install mwrap via RubyGems.org
gem install mwrap
== Usage
mwrap works as an LD_PRELOAD and supplies a mwrap RubyGem executable to
improve ease-of-use. You can set dump_path: in the MWRAP environment
variable to append the results to a log file:
MWRAP=dump_path:/path/to/log mwrap RUBY_COMMAND
# And to display the locations with the most allocations:
sort -k1,1rn </path/to/log | $PAGER
You may also `require "mwrap"' in your Ruby code and use
Mwrap.dump, Mwrap.reset, Mwrap.each, etc.
However, mwrap MUST be loaded via LD_PRELOAD to have any
effect in tracking malloc use. However, it is safe to keep
"require 'mwrap'" in performance-critical deployments,
as overhead is only incurred when used as an LD_PRELOAD.
The output of the mwrap dump is a text file with 3 columns:
total_bytes call_count location
Where location is a Ruby source location (if made under GVL)
or an address retrieved by backtrace_symbols(3). It is
recommended to use the sort(1) command on either of the
first two columns to find the hottest malloc locations.
mwrap 2.0.0+ also supports a Rack application endpoint,
it is documented at:
https://80x24.org/mwrap/MwrapRack.html
== Known problems
* 32-bit machines are prone to overflow (WONTFIX)
== Public mail archives and contact info:
* https://80x24.org/mwrap-public/
* nntps://80x24.org/inbox.comp.lang.ruby.mwrap
* imaps://;AUTH=ANONYMOUS@80x24.org/inbox.comp.lang.ruby.mwrap.0
* https://80x24.org/mwrap-public/_/text/help/#pop3
No subscription will ever be required to post, but HTML mail
will be rejected:
mwrap-public@80x24.org
== Hacking
git clone https://80x24.org/mwrap.git
Send all patches and pull requests (use "git request-pull" to format) to
mwrap-public@80x24.org. We do not use centralized or proprietary messaging
systems.
== License
GPL-2.0+ <https://www.gnu.org/licenses/gpl-2.0.txt>
# heads (aka `branches'):
$ git for-each-ref --sort=-creatordate refs/heads \
--format='%(HEAD) %(refname:short) %(subject) (%(creatordate:short))'
* master README: fixup references to the Perl version (2024-01-08)
heavy mwrap_rack: Rack app to track live allocations (2018-07-16)
# tags:
$ git for-each-ref --sort=-creatordate refs/tags \
--format='%(refname:short) %(subject) (%(creatordate:short))'
v3.0.0-pre1 mwrap 3.0.0-pre1 (2023-01-09) tar.gz
v2.3.0 mwrap 2.3.0 (2022-09-03) tar.gz
v2.2.0 mwrap 2.2.0 (2022-08-22) tar.gz
v2.1.0 mwrap 2.1.0 - heap_page_body struct tracking (2018-08-11) tar.gz
v2.0.0 mwrap 2.0.0 (2018-07-20) tar.gz
v1.0.0 mwrap 1.0.0 - initial release (2018-07-02) tar.gz
# associated public inboxes:
# (number on the left is used for dev purposes)
https://80x24.org/mwrap-public
git clone https://80x24.org/mwrap.git