DTrace Change Log

Below are lists of changes made to DTrace since its initial release in Solaris 10 (10/04). The first list notes the major features (new functions, variables, capabilities, etc.), and the second list includes every bug fix or RFE that was DTrace-related.

Solaris 10 7/05 includes all changes up to an including those in snv_17. Solaris 10 6/06 has only minor DTrace improvements. Future backports to Solaris 10 will similarly synchronize with a particular build.

• Features by Build
• Changes By Build

Features by Build

snv_109

• DTrace CPC Provider

snv_93

• DTrace IP Provider

snv_84

• DTrace NFS v3 Provider
• stddev() aggregating function

snv_80

• DTrace NFS v4 Provider

snv_69

• iSCSI target provider

snv_66

• inet_ntoa(), inet_ntoa6(), inet_ntop() subroutines

snv_58

• sysevent DTrace provider

snv_50

• htons(), htonl(), htonll(), ntohs(), ntohl(), and htohll() subroutines
• _DTRACE_VERSION defined in standard system headers
• dtrace(1M) -G 'guesses' the output bitness

snv_48

• DTrace test suite

snv_38

• is-enabled probes
• fsinfo provider

snv_37

• DTrace support in Zones

snv_35

• DTrace JNI Binding

snv_34

• USDT headergen

snv_30

• printa() with multiple aggregations
• aggregation sorting options

snv_23

• umod()/ufunc()/usym(), mod()/func()/sym()
• allow quantize()/lquantize() increments to be D expressions
• ucaller variable
• flowindent should operate on any probe ending in "-entry"/"-return"

snv_20

• stackdepth variable

snv_16

• fds[] array for file descriptor information

snv_15

• strtok(), strstr(), strchr(), strrchr(), substr(), index(), rindex() subroutines
• support for non-scalar clause-local variables
• optional limit parameter to copyinstr()

snv_11

• dtrace(1M) -lv to show probes argument types and stability

snv_09

• retained enablings to allow for run-time probe matching
• -x and other options for lockstat(1M) and plockstat(1M)

Changes By Build

snv_109

6486156 DTrace cpc provider

snv_108

6791723 Dtrace doesn't populate the fi_pathname in io provider whith UFS directio
6749441 intrstat(1M) shows zeroed values after suspend/resume
6786517 /usr/demo/dtrace/qtime.d tracks enqueue/dequeue times incorrectly

snv_107

No DTrace-related changes.

snv_106

6750659 drti.o crashes app due to corrupt environment

snv_105

No DTrace-related changes.

snv_104

No DTrace-related changes.

snv_103

6738982 Representative thread after DTrace stop() action is incorrect
6737974 DTrace probe module globbing doesn't work
6730287 tst/common/printf/tst.str.d needs to be updated for ZFS boot

snv_102

No DTrace-related changes.

snv_101

No DTrace-related changes.

snv_100

No DTrace-related changes.

snv_99

6737926 getAggregate() method fails to specify anonymous aggregation explicitly
6735480 race between probe enabling and provider registration

snv_98

No DTrace-related changes.

snv_97

6734627 protocmp complains about opt/SUNWdtrt/README after TW -> Hg switch

snv_96

6696397 NFS v3 provider reports all UDP clients as 0.0.0.0

snv_95

No DTrace-related changes.

snv_94

6721057 tst.sdtargs.d fails on 7th sdt arg on amd64
6721426 tst.sdtargs.d passes despite dtrace "invalid address" error
6718877 crgetzoneid() use can cause problems when forking processes with USDT providers in a non global zone

snv_93

6640019 DTrace IP Provider
6655707 sdt arguments are off-by-one past the 5th
6667364 /usr/demo/dtrace/index.html: URLs to dtrace guide chapters wrong

snv_92

6705554 dtrace_disx86() returns incorrect instruction size causing spurious watchpoint traps

snv_91

6685348 Hypervisor event provider for DTrace

snv_90

6677812 race between dtrace activities in non-local zones
6684076 is_enabled at -xO2 and greater causes a functions return value to be over-written

snv_89

6690973 assertion failure during test run (schrock)

snv_88

6583726 race between program and process destruction
6642281 substr() doesn't properly null-terminate
6642734 substr() can do the wrong thing for invalid index values
6642972 substr() is broken with a negative third argument
6646597 library load failures aren't properly propagated to dependents
6654396 new pid probes aren't attached to retained enablings
6654402 user provider clean up needs some work
6663020 fasttrap_pid_probe() wasn't fully updated for amd64
6672627 Code optimizer cause problems for dtrace -G

snv_87

No DTrace-related changes.

snv_86

No DTrace-related changes.

snv_85

6545859 ERROR: /opt/SUNWdtrt/tst/common/java_api/tst.Bean.ksh stdout mismatch
6650894 'dtest -i java' errors
6652174 add "-target 1.5" javac flag to build dtest Java classes
6652183 add "-Xlint" javac flag to Java DTrace API build
6652217 Java DTrace API loses aggregation record order
6667597 Java DTrace API does not handle negative average in avg() action
6667606 Java DTrace API needs to support stddev() action
6668854 DTrace Java tests should run by default
6668856 dtest -u is useless

snv_84

6660173 PSARC 2008/050 DTrace NFS v3 Provider
6660179 fix stability of NFS v4 provider
6325485 A stddev() aggregator would be a nice adjunct to avg()
6618705 p*d123 doesn't cause pid probes to be created
6624541 dtrace aggregations should assume signed arguments
6639830 chkargs Makefile gets a binary from the build machine, and not the works
pace

snv_83

6657340 tst.helper.d on x86 was broken by 4947191

snv_82

6623226 lockstat(1M) causes a system panic

snv_81

No DTrace-related changes.

snv_80

6635086 DTrace NFS v4 Provider

snv_79

6600430 library dependencies for DTrace
6602183 names of all non USDT based providers should be able to end with a digit
6630135 symbols created for dtrace -G should be removed in the final link

snv_78

6624263 syscall/tst.args cannot fail

snv_77

No DTrace-related changes.

snv_76

No DTrace-related changes.

snv_75

6606981 the ucaller variable requires additional checks

snv_74

No DTrace-related changes.

snv_73

6543061 /opt/SUNWdtrt/tst/common/mib/tst.tcp.ksh can hang if fingerd is disabled
6581091 some DTrace test suite tests are not dstyle clean
6581196 many ksh scripts in the DTrace test suite use incorrect SCCS ID string
6581228 some DTrace test suite scripts need to specify a unit for cleanrate
6593038 some D scripts in the test suite contain multiple identical SCCS ident strings

snv_72

6546290 /opt/SUNWdtrt/tst/common/predicates/tst.predcache.ksh : could not unload dtrace
6573659 removing a USDT provider can undermine pid probes
6576041 ERROR: /opt/SUNWdtrt/tst/common/usdt/tst.dlclose1.ksh stdout mismatch
6581257 dtrace_lookup_by_type() can fail spuriously
6582425 tst/common/usdt/tst.forker.ksh can hang
6593326 dtrace test suite failures

snv_71

No DTrace-related changes.

snv_70

6468390 dtrace_canstore()'s mechanism for validating dynamic variable stores needs improving
6578110 The DIF 'ret' instruction doesn't work as advertised
6576371 Tail-call USDT probes can use wrong argument values

snv_69

6533833 A trapstat and ustack()/ustackdepth combination causes problems with invalid contexts
6573073 usdt args[] are incorrectly translated
6574850 dt_idhash_iter() needs to cache the array length
6573074 PSARC 2007/153 iSCSI target provider

snv_68

No DTrace-related changes.

snv_67

No DTrace-related changes.

snv_66

6535590 Pid provider doesn't work with probe "main:entry"
6551723 dtrace's mkdemo.pl causes false positive on inter-workspace wsdiff
6556673 potential deadlock with USDT tear-down and enable
6558517 need DTrace versions of IP address to string functions, like inet_ntop()
6560894 inet_nto* functions need DTrace version number bumped

snv_65

No DTrace-related changes.

snv_64

No DTrace-related changes.

snv_63

6542480 fix for 6534991 broke the nightly build with gcc

snv_62

6533678 dtrace incorrectly resumes execution in the middle of 2-byte int 3 instr
6534035 dtrace_user_probe fails to consider alternate code selectors when checking for int3 functions
6484266 fasttrap needs to check for duplicate offsets
6497891 dtrace -G can fail due to uninitialized data
6504328 mapid disabling isn't enough
6512813 calendar-based DTrace tests fail when not in US/Pacific
6513027 tst.[v]fork.d needs updating for forksys()
6534984 fasttrap emulation code could use some work
6534988 remove the lint work-around from fasttrap
6534991 prepare the DTrace test suite for PIT

snv_61

6479888 dtrace_detach() deadlocks with cpu_configure() via cpu_lock

snv_60

6524709 executables using /usr/lib/libc.so.1 as the ELF interpreter dump core

snv_59

6513018 tst.udp. needs updating
6517428 readObject() methods should call initCause() on InvalidObjectException
6517433 replace StringBuffer with StringBuilder
6521523 aggregation drops can hang the Java DTrace API
6479756 dtrace can cause "panic send mondo timeout"
6512250 dtrace_getustack_common() could be improved

snv_58

6507659 tsc differences between CPU's give dtrace_gethrtime() serious problems
6513863 java_api tests assume that PATH includes current directory
6515452 Program.File deserialization is broken
PSARC 2007/036 sysevent DTrace provider
6517131 sysevent DTrace provider

snv_57

6510395 Add "-target 1.5" to javac build
5030630 bcmp() on x86 cannot be dtraced

snv_56

6436284 ::dtrace dumps core if given anonymous trace state
6488973 Implement DTrace ECB walker
6504126 pid provider probemod test for DTrace test suite
6501469 xref should include dtrace scripts in cscope.out
6494827 OPL dtrace_blksuword32() needs to do a flush
6505802 test suite failure: tst.Bean.ksh
6505806 test suite failure: tst.MultiAggPrinta.ksh
6506495 -DJAVA_DTRACE_MAX_CONSUMERS=N for any N < 8 is treated as if it were 8

snv_55

No DTrace-related changes.

snv_54

6489516 fix up some Makefile issues for dtrace/test
6493158 pid provider having problems matching module names

snv_53

6478725 dtrace_load* are no longer as safe as they used to be.

snv_52

No DTrace-related changes.

snv_51

6458281 dtrace structure tracing problem
6474442 dtrace would benefit from a few extra safety tests
6296612 plockstat dumps core on second call
6478044 dtrace assert: kaddr >= kernelbase && kaddr + size >= kaddr in dtrace_copyin()
6479887 DTRACE_INRANGE incorrectly treats testsz as a signed quantity
6479991 some err.* test cases need work

snv_50

6282214 Byte Ordering Functions in libdtrace
6353438 syscall arguments past the 5th are incorrect
6432394 some sort of #define to denote the availability of USDT
6435862 dtrace -G can generate malformed string tables
6443592 dtrace(1M) leaves a breakpoint in rtld_db_dlactivity on error
6455174 assertion failed: new_pc != 0, file: ../../intel/dtrace/fasttrap_isa.c, line: 1606
6456626 dtrace -G should be able to 'guess' output format
6461522 Availability of dummy-macros for USDT probes in non-DTrace-supported environments
6462995 the syscall provider truncates return values on 32-bit x86 kernels
6465195 assertion failed: -1 <= rmindex && rmindex < tp->ftt_size
6472119 fasttrap should optimize the nop case on x86
6472121 dtest.pl should use the right compilers
6457918 Java DTrace API does not support umod()/ufunc()/usym(), mod()/func()/sym()
6467507 Java DTrace API javadoc links to DTrace guide broken
6468139 ufunc() aggregation key sorts strangely
6470482 Aggregation key integer representation and ordering differs between Java API and libdtrace
6470519 LocalConsumer CLOSED state reverts to STOPPED
6465302 integrate Java DTrace API tests with DTrace test suite
6467526 test suite: sched/tst.stackdepth.d fails in empty stack case

snv_49

6455612 DTrace proc provider should have inline for thread home lgroup

snv_48

6464285 integrate the DTrace test suite

snv_47

6387493 uid variable isn't available to non-root DTrace users
6436283 anonymous tracing is broken on MP systems
6458769 x86 anonymous tracing may not work on non-boot CPUs
6458770 x86 startup is confused for two seconds per slave CPU

snv_46

No DTrace-related changes.

snv_45

No DTrace-related changes.

snv_44

No DTrace-related changes.

snv_43

6430221 few memory leaks from dtrace
6436303 the old fasttrap static probe needs to go
6436364 race between creating and enabling USDT probes

snv_42

No DTrace-related changes.

snv_41

6426129 abort() after close() throws NoSuchElementException
6345226 iotime.d is off by 10
6426934 USDT providers should leave with their load objects
6431036 dtrace_helpers_duplicate() confuses dtrace_helpers_destroy()

snv_40

6419826 USDT DOF is rejected with a plurality of is-enabled probes

snv_39

6413280 lookupKernelFunction() & lookupUserFunction() truncate last char
6410027 ustack() on x86 doesn't match pstack(1)
6414721 it should be legal to have only is-enabled probes
6414729 USDT probes can't be enabled during fork
6414734 $dtrace... symbols appear for static functions containing USDT probes
6414740 processes without DTrace privileges don't auto-enable their USDT probes
6415612 core section headers can be corrupt
6415617 USDT providers with identical names can cause an assertion failure

snv_38

6405927 USDT is-enabled probes
6405929 USDT DOF with zero probes results in an unsatisfiable memory allocation
6405932 dead variables in usr/src/uts/common/dtrace/dtrace.c
6405939 ::dofdump doesn't use section sizes correctly
6399888 stop() hangs if listener calls synchronized Consumer method
6399897 Option class getOption() method should be renamed getName()
6399915 ProbeDescription single arg constructor should parse probedesc
PSARC 2006/196 DTrace Filesystem Info Provider
6405662 add DTrace fsinfo provider
6369582 dtrace fbt:procfs:prgetattr:return probe causes panic
6377362 killing a -xbufpolicy=ring dtrace consumer can panic the system 
6379717 dtrace_dynvar() lookup/dealloc race when dirty list is empty
6380434 dtrace_softstate items consume more space than required
6405658 "failed to grab process" when instrumenting many processes 
6408665 dtrace fails in nightly build

snv_37

4970596 RFE: should be able to run some DTrace programs in a zone
6231905 PRIV_DTRACE_PROC and PRIV_DTRACE_USER don't respect PRIV_PROC_ZONE
6388070 non-root non-global zone users can't get dtrace provider modules to load
6393431 dtrace_proc + proc_owner doesn't sufficiently enable destructive actions

snv_36

6390378 Java DTrace API javadoc permissions inconsistencies
6392748 Java DTrace API class diagram improve gif quality
6395902 use of USDT probes can cause plockstat and other scripts to fail

snv_35

PSARC 2006/054 DTrace JNI Binding
6384263 PSARC 2006/054 DTrace JNI Binding
6217718 plockstat(1m) should sort by total
6381059 libdtrace doesn't correctly detect all x64 jump tables
6381319 the compiler reuses aggregation IDs for disparate aggregations
6384324 plockstat output can be very confusing
6386262 DTrace version needs to be bumped for the update

snv_34

4864945 spelling error in usage message
6299947 ustack() needs to ignore the top 32 bits for 32-bit processes
6305794 libdtrace misses rtld notifications
6309681 USDT headergen
6349088 dtrace command, Assertion failed: dpr->dpr_refs != 0, file ../common/dt_proc.c, line 976
6375841 USDT providers shouldn't be allowed to end in a digit

snv_33

No DTrace-related changes.

snv_32

6198296 dtrace's printf() misses a corner case
6235357 dtrace(1M) can't ignore SIGINT and SIGTERM
6282866 D string behaviors need some cleanup
6304467 dtrace -G by itself does nothing and produces no output
6305443 dtrace falls for typedef fake
6312329 qlen.d example won't parse
6312678 D compiler needs to resolve direct_declarator IDENT/TNAME ambiguity
6320980 ctf_enum_value() returns NULL instead of CTF_ERR on failure
6368524 ctf_lookup_by_name() qualifier check can be made more efficient
6368529 Psetbkpt() is returning EBUSY instead of setting errno to EBUSY
6370454 dtrace should support USDT probes in static functions

snv_31

6356708 libdtrace should interrogate providers, open devices via /dev.

snv_30

6340196 Probe effect when using strings in aggregations could be reduced
6350217 printa() refuses to use %Y/%T format specifiers
6350219 aggregation/assoc. array error messages should use "key" nomenclature
6350221 undefined behavior when lquantize() is used inconsistently
6350223 printa() should support multiple aggregations
6350224 need aggregation sorting options
6350225 need private dtrace(1M) option for buffered handler debugging
6357600 zero value in AGGKEY bufhandler does not match buffered output
6357949 lockstat fails with "bad quantize size in aggregation record"
6309410 gcc and SPARC-specific dtrace code don't get along

snv_29

6332949 V240 panics with kmem_flags set, buffer corruption in streams/Dtrace while testing arbitrary patches
6340028 assertion failed: dtrace_deferred_pid != NULL, file: ../../common/dtrace/dtrace.c, line: 12485

snv_28

No DTrace-related changes.

snv_27

No DTrace-related changes.

snv_26

6334302 dtrace panic the system when enabling probes.

snv_25

5094814 dtrace user return probe trap causes assertion failure
6322760 dt_pid.c needs to rework its use of xyerror()
6327139 pid provider link map handling is inconsistent
6330782 ustackdepth may not always match the depth of ustack()
6330787 threads with no user context can report bogus ustacks

snv_24

5072038 binaries shouldn't be stripped
6319069 multiple providers can't instrument the same user-land instruction
6254145 Assertion failed: dpr != NULL, file ../common/dt_proc.c, line 629
6304960 Instrumentation of "ret" needs to be more sophisticated
6324319 runtime dtrace options work only by chance

snv_23

6256581 System got a hang or a panic with dtrace+kmdb
6264573 unanchored dtrace_getpcstack is rather imprecise toward function end
6289517 dtrace doesn't like fd_intr anymore 
6291378 dtrace helpers can interfere with the use of kmdb     
6295554 dtrace doesn't report errors in ERROR probes
6311947 add umod()/ufunc()/usym(), mod()/func()/sym()
6311952 buffered handler should be called after printing each tuple element
6311956 drops induced by END are not recorded
6311958 should indicate missing jstack() frames due to string table overflows
6311960 allow some DTrace options to be set dynamically
6311963 jstack() produces stacks packed with "StubRoutines"
6311975 allow boolean DTrace options to be unset
6315028 allow quantize()/lquantize() increments to be D expressions
6315033 add dtrace_addr2str()/dtrace_uaddr2str() to libdtrace API
6315034 add ucaller variable
6315035 enablings containing USDT probes are not dynamically reevaluated
6315037 cannot aggregate on the return value of some subroutines
6315039 including  in a D script induces compile-time error
6315087 stack() not correctly printed for 32-bit consumers on amd64 kernel
6315975 flowindent should operate on any probe ending in "-entry"/"-return"
6317350 symbol tables should not be discarded for UNDEAD processes
6320437 ::difo doesn't always properly align its output
6320438 helper tracing should trace detailed error information
6320439 aggregations with negative values are not properly sorted
6320440 quantizations with values in zero bucket are not properly sorted
6320443 linear quantizations with values beyond range aren't properly printed
6320445 need mechanism for ustack helpers to annotate frames
6320447 %d doesn't work properly for printa() of aggregation w/ negative values
6320449 helpers should be able to call string-related subroutines

snv_22

6303188 some dtrace scripts with speculations fail to load
6304654 predicates containing args[] references may be incorrectly cached
6272865 race condition between SIGKILL and /proc PCAGENT
6295588 intrstat reports statistics incorrectly

snv_21

6275414 unary operator * doesn't work properly when applied to args[] elements
6282291 D compiler core dumps in dt_node_dynamic() for inline parameter
6295808 dtrace could warn about /* w/i a comment
6301080 dtrace debugging support should be easier to maintain
6301082 mdb should provide raw target support for DOF
6301083 dt_probe_discover() fails assertion when matching unpublished provider
6301086 dtrace(1M) should always dtrace_close() before returning
6301087 dtrace_close() deadlock in dt_proc_destroy() when processes are idle
6301088 dtrace_program_link() leaks ELF handles for object files
6301091 D compiler support for USDT translators (part 2)
6303053 pid provider panic under low memory conditions

snv_20

4970475 There should be a stackdepth equivalent for userland
5084954 value of dip can be incorrect in autovec
6181505 dtrace sysinfo:::modload probe does not fire when using 'modload'
6265417 schedctl-yield isn't listed in sdt_subr.c
6272558 gcc and dtrace don't get along
6276101 dtrace -G behaves strangely with multiple scripts
6284880 intrstat can leak dynamic variable state
6295662 plockstat needs more characters for stack addresses
6296903 invalid memory accesses clear other DTrace error bits

snv_19

No DTrace-related changes.

snv_18

No DTrace-related changes.

snv_17

6258738 fbt refuses to instrument functions starting with branches
6264469 fbt is confused by jump tables in code
6264473 fbt is confused by the return instruction
6276979 dtrace needs some clean up
6278983 SDT misbehaves for gcc-compiled kernel modules on SPARC

snv_16

6267117 Arguments are incorrectly printed for fbt provider on amd64
5108961 vestigial kadb turds left in dtrace
6214615 Conversion of bufinfo_t's b_resid is not defined in the io.d translator
6225650 D compiler can't resolve past implicit forward declarations
6267670 dt_type_pointer() should report reason for failure
6267671 ctf_add_type() fails when definition added after forward declaration
6267680 D compiler should not permit void parameters to have names
6267682 D compiler is not checking array redeclarations properly
6267693 D compiler support for inline associative array references
6267695 DTrace should provide a fds[] array for file descriptor information

snv_15

6259805 Enabling compilation of ON with Studio 10 compilers for x86
6265086 DTrace has anemic string handling facilities
6265087 clause-local D variables can only be scalars
6265088 storing NULL to by-reference static variables induces an error
6265090 need mechanism to redirect stdout from within a D script
6265094 copyinstr() should take optional limit parameter

snv_14

6254258 dtrace doesn't pick up usdt probes in dlopened objects
6254741 usdt generation can do the wrong thing with tail calls

snv_13

6217821 dtrace cmd fails assertion in dt_proc_lock()
6219195 lockstat under Solaris10 unacceptably degrades performance
6223379 lockstat fails to report one stack frame
6253027 bufpolicy of "fill" or "ring" causes dtrace(1M) to consume 100% of CPU
6253028 dtrace_probe()/dtrace_state_go() race can induce D data corruption
6253030 adding an action to an ECB takes quadratic time
6253031 dtrace_consume() can (still) call record callbacks with bad argument
6253033 aggregations should be sorted on key as well as value

snv_12

No DTrace-related changes.

snv_11

6234072 pid provider mishandles recursive returns
6232748 pid provider can miss recursive function returns
5029967 dtrace should provide an option to show probe argument types, stability
6231207 libdtrace is not able to properly resolve some probe argument types
6234004 libctf should support interfaces for client data in ctf_file_t's
6234033 ctf_type_name() should return NULL if input fp is NULL
6234037 D strchr2esc() incorrectly includes sign extension bit
6234063 D compiler support for USDT translators (part 1)
6234449 ctf_lookup_by_name() fails when typedef is a qualifier substring
6236617 D compiler support for restrict keyword
6236726 ustack() at pid provider return probes can be confusing
6237196 pmap does not label thread stacks as documented
6238322 fasttrap::fasttrap:fasttrap args are broken on amd64
6239626 helpers aren't backward compatible with S10

snv_10

6216776 wrong function name for sysinfo:::modunload
6226263 usdt probes will fail to instantiate if pid probes are specified first
6228044 the pid provider can miss some function returns
6229159 dtrace should be able to trace dynamically loaded objects
6230315 pid123::ioctl:return finds the wrong instruction

snv_09

6226302 must allow enablings to be retained and rematched
6226320 must allow enablings to be duplicated after tracing is enabled
6226345 dtrace_consume() can call record callbacks with incorrect argument
PSARC 2005/052 plockstat(1M) and lockstat(1M) options
6197606 plockstat could have a lower overhead
6221490 plockstat(1M) needs options to set aggsize and aggrate
6221495 plockstat(1M) needs a verbose option to report when tracing has
6221496 plockstat(1M) should have an option to exit after a time limit
6221498 plockstat(1M) should have an option to limit number of entries
6223603 the pid provider is willing to instrument things it shouldn't

snv_08

6218854 USDT and the jstack() action don't work on processes on a zone
6220843 dt_pid should look for PR_OBJ_LDSO rather than ld.so

snv_07

6213962 dtrace -G doesn't work on sparcv8+ object files

snv_06

No DTrace-related changes.

snv_05

No DTrace-related changes.

snv_04

No DTrace-related changes.

snv_03

No DTrace-related changes.

snv_02

No DTrace-related changes.

snv_01

No DTrace-related changes.