$ git log --pretty=format:'%h %s (%cs)%d'
d15143e support malloc tracing and replay (2024-04-06)
(HEAD -> master)
403b495 reduce branches for size class calculation (2024-04-06)
9165093 malloc: revert file-backed mmap, sbrk for main arena (2024-04-03)
c483900 implement dynamic mmap threshold (2024-04-03)
43f7548 dlmalloc: use jemalloc-inspired size classes (2024-04-03)
b48073f avoid redundant assignment (2024-04-02)
9046971 fix build with 5.36 (2024-03-12)
6b67297 README: link to Ruby version, too (2024-01-09)
7200d0e location_name: fix uninitialized variable warnings (2023-05-06)
1c99226 allow mremap and MAP_ANONYMOUS for large allocations (2023-02-22)
...
$ git cat-file blob HEAD:README
Devel::Mwrap - LD_PRELOAD malloc wrapper + malloc line stats for Perl
Devel::Mwrap is designed to answer the question:
Which lines of Perl are hitting malloc the most?
Devel::Mwrap wraps all malloc-family calls to trace the Perl
source location of such calls and bytes allocated at each
callsite. It is primarily designed to identify high memory use,
but may function as a leak detector as it can show live
allocations at every call site. Depending on your application
and workload, the overhead is roughly a 50%-100% increase memory
and runtime.
It also gives configurable backtraces of all dynamically-linked
malloc callsites for any program where backtrace(3) works,
including programs not linked to Perl.
It is thread-safe and requires the concurrent lock-free hash table
from the Userspace RCU project: https://liburcu.org/
It relies on dynamic linking to a malloc(3) implementation. If
you got Perl from your OS distribution, this typically does not
require rebuilding Perl.
Tested on the `perl' package distributed with:
* Debian GNU/Linux 10 and 11
* FreeBSD 12.x
It may work on NetBSD, OpenBSD and DragonFly BSD.
== Install
See `INSTALL' document
== Usage
Devel::Mwrap works as an LD_PRELOAD and supplies a mwrap-perl wrapper to
improve ease-of-use. You can set dump_csv: in the MWRAP environment
variable to append the results to a CSV file:
MWRAP=dump_csv:/path/to/csv.%p mwrap-perl COMMAND
For long running processes, you can see the AF_UNIX HTTP interface:
MWRAP=socket_dir:/some/dir mwrap-perl COMMAND
And connect via `curl --unix-socket /some/dir/$PID.sock' or `mwrap-rproxy'.
See mwrap-rproxy(1p) and mwrap-perl(1p) manpages for more info.
== Compared to other tools
* mwrap-perl knows about Perl code, and an `mwrap' RubyGem exists, too:
https://80x24.org/mwrap.git
* mwrap does not catch memory errors; use ASan, valgrind, or similar
* mwrap is reasonably fast, fast enough for the author to run on
production-facing Perl daemons
* the AF_UNIX HTTP interface allows inspecting live processes without
interruption instead of waiting for an exit dump
== Known problems
* 32-bit machines are prone to overflow (WONTFIX)
* signalfd(2)-reliant code will need latest URCU with commit
ea3a28a3f71dd02f (Disable signals in URCU background threads, 2022-09-23)
* Perl source files over 16.7 million lines long are not supported :P
* large C backtraces (off by default) are expensive for large programs
== Public mail archives (HTTP, Atom feeds, IMAP mailbox, NNTP group, POP3):
https://80x24.org/mwrap-perl/
imaps://;AUTH=ANONYMOUS@80x24.org/inbox.comp.lang.perl.mwrap.0
nntps://80x24.org/inbox.comp.lang.perl.mwrap
https://80x24.org/mwrap-perl/_/text/help/#pop3
No subscription nor real identities will ever be required to obtain
support or contribute, HTML mail is rejected. Memory usage reductions
start with you; only send plain-text mail to us and do not top-post.
HTML mail and top-posting costs everybody memory and bandwidth.
mwrap-perl@80x24.org
== Hacking
git clone https://80x24.org/mwrap-perl.git
Send all patches ("git format-patch" + "git send-email") and
pull requests (use "git request-pull" to format) via email
to mwrap-perl@80x24.org. We do not and will not use
proprietary messaging systems.
== License
GPL-3.0+ <https://www.gnu.org/licenses/gpl-3.0.txt>
# heads (aka `branches'):
$ git for-each-ref --sort=-creatordate refs/heads \
--format='%(HEAD) %(refname:short) %(subject) (%(creatordate:short))'
* master support malloc tracing and replay (2024-04-06)
# tags:
$ git for-each-ref --sort=-creatordate refs/tags \
--format='%(refname:short) %(subject) (%(creatordate:short))'
# no tags, yet...
# associated public inboxes:
# (number on the left is used for dev purposes)
https://80x24.org/mwrap-perl
git clone https://80x24.org/mwrap-perl.git