Bug 15533 - LD_AUDIT introduces an avoidable performance degradation
Summary: LD_AUDIT introduces an avoidable performance degradation
Status: RESOLVED FIXED
Alias: None
Product: glibc
Classification: Unclassified
Component: dynamic-link (show other bugs)
Version: unspecified
: P2 normal
Target Milestone: 2.35
Assignee: Not yet assigned to anyone
URL:
Keywords:
Depends on:
Blocks:
 
Reported: 2013-05-24 23:56 UTC by Alexander Monakov
Modified: 2021-12-28 11:51 UTC (History)
2 users (show)

See Also:
Host:
Target:
Build:
Last reconfirmed:
fweimer: security-

Attachments
testcase (439 bytes, application/x-gtar)
2013-05-24 23:56 UTC, Alexander Monakov 		Details
View All Add an attachment (proposed patch, testcase, etc.)

Note You need to log in before you can comment on or make changes to this bug.
Description Alexander Monakov 2013-05-24 23:56:08 UTC 
Created attachment 7044 [details]
testcase

Introducing an audit library currently force-enables instrumenting for profiling in the dynamic linker (as if LD_AUDIT implied LD_PROFILE).  However, this is not necessary if the audit library does not provide la_plt{enter,exit} symbols.

Attached testcase demonstrates the performance hit:

$ make test
time ./main
0.47user 0.00system 0:00.48elapsed 99%CPU (0avgtext+0avgdata 1984maxresident)k
0inputs+0outputs (0major+170minor)pagefaults 0swaps
time env LD_AUDIT=./libaudit.so ./main
8.96user 0.00system 0:08.97elapsed 99%CPU (0avgtext+0avgdata 3264maxresident)k
0inputs+0outputs (0major+442minor)pagefaults 0swaps
Comment 1 Alexander Monakov 2013-05-25 00:27:35 UTC 
Patch: http://sourceware.org/ml/libc-alpha/2013-05/msg00888.html
Comment 2 Nathan Nye 2021-10-05 20:11:44 UTC 
This patch causes la_symbind64 to no longer run (also I assume la_symbind32), so the scope isn't limited to just the la_plt{enter,exit} functions.
Comment 3 Adhemerval Zanella 2021-12-28 11:51:58 UTC 
Fixed on 2.35 (063f9ba220f434c7f30dd65c4cff17c0c458a7cf).