In addition to a CPU cache simulator, other analysis tools are available that operate on memory address traces. Which tool is used can be selected with the -simulator_type parameter. New, custom tools can also be created, as described in Creating New Analysis Tools.

Cache Simulator

This is the default tool. Here is an exmample of running it on an offline trace:

$ bin64/drrun -t drcachesim -offline -- ~/test/pi_estimator
Estimation of pi is 3.142425985001098
$ bin64/drrun -t drcachesim -indir drmemtrace.*.dir
Cache simulation results:
Core #0 (1 thread(s))
  L1I stats:
    Hits:                          258,433
    Misses:                          1,148
    Miss rate:                        0.44%
  L1D stats:
    Hits:                           93,654
    Misses:                          2,624
    Prefetch hits:                     458
    Prefetch misses:                 2,166
    Miss rate:                        2.73%
Core #1 (1 thread(s))
  L1I stats:
    Hits:                            8,895
    Misses:                             99
    Miss rate:                        1.10%
  L1D stats:
    Hits:                            3,448
    Misses:                            156
    Prefetch hits:                      26
    Prefetch misses:                   130
    Miss rate:                        4.33%
Core #2 (1 thread(s))
  L1I stats:
    Hits:                            4,150
    Misses:                            101
    Miss rate:                        2.38%
  L1D stats:
    Hits:                            1,578
    Misses:                            130
    Prefetch hits:                      25
    Prefetch misses:                   105
    Miss rate:                        7.61%
Core #3 (0 thread(s))
LL stats:
    Hits:                            1,414
    Misses:                          2,844
    Prefetch hits:                     824
    Prefetch misses:                 1,577
    Local miss rate:                 66.79%
    Child hits:                    370,667
    Total miss rate:                  0.76%

TLB Simulator

To simulate TLB devices instead of caches, pass TLB to -simulator_type:

$ bin64/drrun -t drcachesim -simulator_type TLB -- ~/test/pi_estimator
Estimation of pi is 3.142425985001098
---- <application exited with code 0> ----
TLB simulation results:
Core #0 (1 thread(s))
  L1I stats:
    Hits:                          252,412
    Misses:                            401
    Miss rate:                        0.16%
  L1D stats:
    Hits:                           87,132
    Misses:                          9,127
    Miss rate:                        9.48%
  LL stats:
    Hits:                            9,315
    Misses:                            213
    Local miss rate:                  2.24%
    Child hits:                    339,544
    Total miss rate:                  0.06%
Core #1 (1 thread(s))
  L1I stats:
    Hits:                            8,709
    Misses:                             20
    Miss rate:                        0.23%
  L1D stats:
    Hits:                            3,544
    Misses:                             55
    Miss rate:                        1.53%
  LL stats:
    Hits:                               15
    Misses:                             60
    Local miss rate:                 80.00%
    Child hits:                     12,253
    Total miss rate:                  0.49%
Core #2 (1 thread(s))
  L1I stats:
    Hits:                            1,622
    Misses:                             21
    Miss rate:                        1.28%
  L1D stats:
    Hits:                              689
    Misses:                             35
    Miss rate:                        4.83%
  LL stats:
    Hits:                                3
    Misses:                             53
    Local miss rate:                 94.64%
    Child hits:                      2,311
    Total miss rate:                  2.24%
Core #3 (0 thread(s))

Reuse Distance

To compute reuse distance metrics:

$ bin64/drrun -t drcachesim -simulator_type reuse_distance -reuse_distance_histogram -- ~/test/pi_estimator
Estimation of pi is 3.142425985001098
---- <application exited with code 0> ----
Reuse distance tool aggregated results:
Total accesses: 349632
Unique accesses: 196603
Unique cache lines accessed: 4235
 
Reuse distance mean: 14.64
Reuse distance median: 1
Reuse distance standard deviation: 104.10
Reuse distance histogram:
Distance       Count  Percent  Cumulative
       0      153029   44.36%   44.36%
       1      101294   29.37%   73.73%
       2       14116    4.09%   77.82%
       3       14248    4.13%   81.95%
       4        8894    2.58%   84.53%
       5        2733    0.79%   85.32%
...
==================================================
Reuse distance tool results for shard 29327 (thread 29327):
Total accesses: 335084
Unique accesses: 187927
Unique cache lines accessed: 4148
 
Reuse distance mean: 14.77
Reuse distance median: 1
Reuse distance standard deviation: 106.02
Reuse distance histogram:
Distance       Count  Percent  Cumulative
       0      147157   44.47%   44.47%
       1       96820   29.26%   73.72%
       2       13613    4.11%   77.84%
       3       13834    4.18%   82.02%
       4        8666    2.62%   84.64%
       5        2552    0.77%   85.41%
...
    3658          29    0.01%  100.00%
    3851           1    0.00%  100.00%
 
Reuse distance threshold = 100 cache lines
Top 10 frequently referenced cache lines
        cache line:     #references   #distant refs
    0x7f2a86b3fd80:        27980,            0
    0x7f2a86b3fdc0:        18823,            0
    0x7f2a88388fc0:        16409,          111
    0x7f2a8838abc0:        15176,            6
    0x7f2a883884c0:         9930,           20
    0x7f2a88388480:         7944,           20
    0x7f2a88388500:         7574,           20
    0x7f2a88398d00:         7390,          100
    0x7f2a86b3fd40:         6668,            0
    0x7f2a88388440:         5717,           20
Top 10 distant repeatedly referenced cache lines
        cache line:     #references   #distant refs
    0x7f2a885a4180:          246,          132
    0x7f2a87504ec0:          202,          128
    0x7f2a875044c0:          323,          126
    0x7f2a885a4480:          220,          126
    0x7f2a87504f00:          293,          124
    0x7f2a86fd7e00:          289,          124
    0x7f2a875049c0:          221,          124
    0x7f2a875053c0:          270,          122
    0x7f2a86db9c00:          269,          122
    0x7f2a875047c0:          201,          122
 
==================================================
Reuse distance tool results for shard 29328 (thread 29328):
Total accesses: 12216
Unique accesses: 7251
Unique cache lines accessed: 319
 
Reuse distance mean: 12.98
Reuse distance median: 1
Reuse distance standard deviation: 38.19
Reuse distance histogram:
Distance       Count  Percent  Cumulative
       0        4965   41.73%   41.73%
       1        3758   31.59%   73.32%
       2         411    3.45%   76.78%
       3         348    2.93%   79.70%
       4         179    1.50%   81.21%
       5         152    1.28%   82.48%
...

Reuse Time

A reuse time tool is also provided, which counts the total number of memory accesses (without considering uniqueness) between accesses to the same address:

$ bin64/drrun -t drcachesim -simulator_type reuse_time -- ~/test/pi_estimator
Estimation of pi is 3.142425985001098
---- <application exited with code 0> ----
Reuse time tool aggregated results:
Total accesses: 88281
Total instructions: 261315
Mean reuse time: 433.47
Reuse time histogram:
Distance       Count  Percent  Cumulative
       1       27893   32.84%      32.84%
       2       10948   12.89%      45.73%
       3        5789    6.82%      52.54%
...
==================================================
Reuse time tool results for shard 29482 (thread 29482):
Total accesses: 84194
Total instructions: 250854
Mean reuse time: 450.01
Reuse time histogram:
Distance       Count  Percent  Cumulative
       1       26677   32.86%      32.86%
       2       10508   12.95%      45.81%
       3        5427    6.69%      52.50%
...
==================================================
Reuse time tool results for shard 29483 (thread 29483):
Total accesses: 3411
Total instructions: 8805
Mean reuse time: 86.36
Reuse time histogram:
Distance       Count  Percent  Cumulative
       1        1014   31.56%      31.56%
       2         363   11.30%      42.86%
       3         308    9.59%      52.44%

Event Counts

To simply see the counts of instructions and memory references broken down by thread use the basic counts tool:

$ bin64/drrun -t drcachesim -simulator_type basic_counts -- ~/test/pi_estimator
Estimation of pi is 3.142425985001098
---- <application exited with code 0> ----
Basic counts tool results:
Total counts:
      134566 total (fetched) instructions
       13838 total unique (fetched) instructions
         423 total non-fetched instructions
           0 total prefetches
       30919 total data loads
       13122 total data stores
           0 total icache flushes
           0 total dcache flushes
           3 total threads
        1134 total scheduling markers
           5 total transfer markers
          10 total function id markers
           0 total function return address markers
          30 total function argument markers
           5 total function return value markers
           0 total physical address + virtual address marker pairs
           0 total physical address unavailable markers
          75 total system call number markers
           0 total blocking system call markers
          12 total other markers
           0 total encodings
Thread 64951 counts:
      130900 (fetched) instructions
       13469 unique (fetched) instructions
         423 non-fetched instructions
           0 prefetches
       29844 data loads
       12594 data stores
           0 icache flushes
           0 dcache flushes
        1072 scheduling markers
           5 transfer markers
           4 function id markers
           0 function return address markers
          12 function argument markers
           2 function return value markers
           0 physical address + virtual address marker pairs
           0 physical address unavailable markers
          56 system call number markers
           0 blocking system call markers
           4 other markers
           0 encodings
Thread 64958 counts:
        1861 (fetched) instructions
        1009 unique (fetched) instructions
           0 non-fetched instructions
           0 prefetches
         538 data loads
         262 data stores
           0 icache flushes
           0 dcache flushes
          30 scheduling markers
           0 transfer markers
           2 function id markers
           0 function return address markers
           6 function argument markers
           1 function return value markers
           0 physical address + virtual address marker pairs
           0 physical address unavailable markers
           9 system call number markers
           0 blocking system call markers
           4 other markers
           0 encodings
Thread 64959 counts:
        1805 (fetched) instructions
         978 unique (fetched) instructions
           0 non-fetched instructions
           0 prefetches
         537 data loads
         266 data stores
           0 icache flushes
           0 dcache flushes
          32 scheduling markers
           0 transfer markers
           4 function id markers
           0 function return address markers
          12 function argument markers
           2 function return value markers
           0 physical address + virtual address marker pairs
           0 physical address unavailable markers
          10 system call number markers
           0 blocking system call markers
           4 other markers
           0 encodings

The non-fetched instructions are x86 string loop instructions, where subsequent iterations do not incur a fetch. They are included in the trace as a different type of trace entry to support core simulators in addition to cache simulators.

Opcode Mix

The opcode_mix tool uses the non-fetched instruction information along with the preserved libraries and binaries from the traced execution to gather more information on each executed instruction than was stored in the trace. To run on online traces, pass the -instr_encodings option. The results are broken down by the opcodes used in DR's IR, where for x86 mov is split into a separate opcode for load and store but both have the same public string "mov":

$ bin64/drrun -t drcachesim -offline -- ~/test/pi_estimator
Estimation of pi is 3.142425985001098
$ bin64/drrun -t drcachesim -simulator_type opcode_mix -indir drmemtrace.*.dir
Opcode mix tool results:
         267271 : total executed instructions
          36432 :       mov
          31075 :       mov
          24715 :       add
          22579 :      test
          22539 :       cmp
          12137 :       lea
          11136 :       jnz
          10568 :     movzx
          10243 :        jz
           9056 :       and
           8064 :       jnz
           7279 :        jz
           5659 :      push
           4528 :       sub
           4357 :       pop
           4001 :       shr
           3427 :      jnbe
           2634 :       mov
           2469 :       shl
           2344 :        jb
           2291 :       ret
           2178 :       xor
           2164 :      call
           2111 :   pcmpeqb
           1472 :    movdqa
...

Human-Readable View

The view tool prints out the contents of the trace for human viewing, including disassembling instructions in AT&T, Intel, Arm, or DR format (to see disassembly for online traces, pass the -instr_encodings option). The -skip_refs and -sim_refs flags can be used to set a start point and end point for the disassembled view. Note that these flags compute the number of trace entry records which are skipped or displayed which is distinct from the number of instruction records.

The tool displays loads and stores, as well as metadata marker entries for timestamps, on which core and thread the subsequent instruction sequence was executed, and kernel and system call transfers (these correspond to signal or event handler interruptions of the regular execution flow).

In its first two columns, the tool displays the trace record ordinal and the instruction fetch ordinal.

$ $ bin64/drrun -t drcachesim -simulator_type view -indir drmemtrace.*.dir -sim_refs 20
Output format:
<--record#-> <--instr#->: <---tid---> <record details>
------------------------------------------------------------
           1           0:     3256418 <marker: version 6>
           2           0:     3256418 <marker: filetype 0x240>
           3           0:     3256418 <marker: cache line size 64>
           4           0:     3256418 <marker: chunk instruction count 1024>
           5           0:     3256418 <marker: page size 4096>
           6           0:     3256418 <marker: timestamp 13312410768080478>
           7           0:     3256418 <marker: tid 3256418 on core 7>
           8           1:     3256418 ifetch       3 byte(s) @ 0x00007fc205a61940 48 89 e7             mov    %rsp, %rdi
           9           2:     3256418 ifetch       5 byte(s) @ 0x00007fc205a61943 e8 b8 0c 00 00       call   $0x00007fc205a62600
          10           2:     3256418 write        8 byte(s) @ 0x00007fff9a9e3528 by PC 0x00007fc205a61943
          11           3:     3256418 ifetch       1 byte(s) @ 0x00007fc205a62600 55                   push   %rbp
          12           3:     3256418 write        8 byte(s) @ 0x00007fff9a9e3520 by PC 0x00007fc205a62600
          13           4:     3256418 ifetch       3 byte(s) @ 0x00007fc205a62601 48 89 e5             mov    %rsp, %rbp
          14           5:     3256418 ifetch       2 byte(s) @ 0x00007fc205a62604 41 57                push   %r15
          15           5:     3256418 write        8 byte(s) @ 0x00007fff9a9e3518 by PC 0x00007fc205a62604
          16           6:     3256418 ifetch       2 byte(s) @ 0x00007fc205a62606 41 56                push   %r14
          17           6:     3256418 write        8 byte(s) @ 0x00007fff9a9e3510 by PC 0x00007fc205a62606
          18           7:     3256418 ifetch       2 byte(s) @ 0x00007fc205a62608 41 55                push   %r13
          19           7:     3256418 write        8 byte(s) @ 0x00007fff9a9e3508 by PC 0x00007fc205a62608
          20           8:     3256418 ifetch       2 byte(s) @ 0x00007fc205a6260a 41 54                push   %r12
View tool results:
              8 : total instructions

An example of thread switches:

------------------------------------------------------------
       46        0:  3264758 <marker: timestamp 13312413437398055>
       47        0:  3264758 <marker: tid 3264758 on core 2>
       48        1:  3264758 ifetch       3 byte(s) @ 0x00007f4ea89e4940 48 89 e7             mov    %rsp, %rdi
       49        2:  3264758 ifetch       5 byte(s) @ 0x00007f4ea89e4943 e8 b8 0c 00 00       call   $0x00007f4ea89e5600
       50        2:  3264758 write        8 byte(s) @ 0x00007ffd93a0cf18 by PC 0x00007f4ea89e4943
...
  2854543  2149665:  3264758 ifetch       5 byte(s) @ 0x00007f4ea7c87f8c b8 0e 00 00 00       mov    $0x0000000e, %eax
  2854544  2149666:  3264758 ifetch       2 byte(s) @ 0x00007f4ea7c87f91 0f 05                syscall
------------------------------------------------------------
  2854545  2149666:  3264760 <marker: timestamp 13312413438835999>
  2854546  2149666:  3264760 <marker: tid 3264760 on core 11>
  2854547  2149667:  3264760 ifetch       3 byte(s) @ 0x00007f4ea7d0b099 48 85 c0             test   %rax, %rax
  2854548  2149668:  3264760 ifetch       2 byte(s) @ 0x00007f4ea7d0b09c 7c 18                jl     $0x00007f4ea7d0b0b6
...

Here is an example of a signal handler interrupting the regular flow, with metadata showing that the signal was delivered just after an untaken conditional branch:

801343      601827:     1159769 ifetch       2 byte(s) @ 0x00007fc2c3aa5c70 75 57                jnz    $0x00007fc2c3aa5cc9 (untaken)
801344      601827:     1159769 <marker: kernel xfer from 0x7fc2c3aa5c72 to handler>
801345      601827:     1159769 <marker: timestamp 13335923552684013>
801346      601827:     1159769 <marker: tid 1159769 on core 7>
801347      601828:     1159769 ifetch       1 byte(s) @ 0x00007fc2c03fa259 55                   push   %rbp
801348      601828:     1159769 write        8 byte(s) @ 0x00007fff8044e930 by PC 0x00007fc2c03fa259
801349      601829:     1159769 ifetch       3 byte(s) @ 0x00007fc2c03fa25a 48 89 e5             mov    %rsp, %rbp
801350      601830:     1159769 ifetch       3 byte(s) @ 0x00007fc2c03fa25d 89 7d fc             mov    %edi, -0x04(%rbp)
801351      601830:     1159769 write        4 byte(s) @ 0x00007fff8044e92c by PC 0x00007fc2c03fa25d
801352      601831:     1159769 ifetch       4 byte(s) @ 0x00007fc2c03fa260 48 89 75 f0          mov    %rsi, -0x10(%rbp)
801353      601831:     1159769 write        8 byte(s) @ 0x00007fff8044e920 by PC 0x00007fc2c03fa260
801354      601832:     1159769 ifetch       4 byte(s) @ 0x00007fc2c03fa264 48 89 55 e8          mov    %rdx, -0x18(%rbp)
801355      601832:     1159769 write        8 byte(s) @ 0x00007fff8044e918 by PC 0x00007fc2c03fa264
801356      601833:     1159769 ifetch       4 byte(s) @ 0x00007fc2c03fa268 83 7d fc 1a          cmp    -0x04(%rbp), $0x1a
801357      601833:     1159769 read         4 byte(s) @ 0x00007fff8044e92c by PC 0x00007fc2c03fa268
801358      601834:     1159769 ifetch       2 byte(s) @ 0x00007fc2c03fa26c 75 0f                jnz    $0x00007fc2c03fa27d (untaken)
801359      601835:     1159769 ifetch       6 byte(s) @ 0x00007fc2c03fa26e 8b 05 c0 3e 00 00    mov    <rel> 0x00007fc2c03fe134, %eax
801360      601835:     1159769 read         4 byte(s) @ 0x00007fc2c03fe134 by PC 0x00007fc2c03fa26e
801361      601836:     1159769 ifetch       3 byte(s) @ 0x00007fc2c03fa274 83 c0 01             add    $0x01, %eax
801362      601837:     1159769 ifetch       6 byte(s) @ 0x00007fc2c03fa277 89 05 b7 3e 00 00    mov    %eax, <rel> 0x00007fc2c03fe134
801363      601837:     1159769 write        4 byte(s) @ 0x00007fc2c03fe134 by PC 0x00007fc2c03fa277
801364      601838:     1159769 ifetch       1 byte(s) @ 0x00007fc2c03fa27d 90                   nop
801365      601839:     1159769 ifetch       1 byte(s) @ 0x00007fc2c03fa27e 5d                   pop    %rbp
801366      601839:     1159769 read         8 byte(s) @ 0x00007fff8044e930 by PC 0x00007fc2c03fa27e
801367      601840:     1159769 ifetch       1 byte(s) @ 0x00007fc2c03fa27f c3                   ret (target 0x7fc2c3a5af90)
801368      601840:     1159769 read         8 byte(s) @ 0x00007fff8044e938 by PC 0x00007fc2c03fa27f
801369      601841:     1159769 ifetch       7 byte(s) @ 0x00007fc2c3a5af90 48 c7 c0 0f 00 00 00 mov    $0x0000000f, %rax
801370      601842:     1159769 ifetch       2 byte(s) @ 0x00007fc2c3a5af97 0f 05                syscall
801371      601842:     1159769 <marker: system call 15>
801372      601842:     1159769 <marker: timestamp 13335923552684023>
801373      601842:     1159769 <marker: tid 1159769 on core 7>
801374      601842:     1159769 <marker: syscall xfer from 0x7fc2c3a5af99>
801375      601842:     1159769 <marker: timestamp 13335923552684029>
801376      601842:     1159769 <marker: tid 1159769 on core 7>
801377      601843:     1159769 ifetch       4 byte(s) @ 0x00007fc2c3aa5c72 48 83 c4 48          add    $0x48, %rsp

View Function Calls

The func_view tool records function argument and return values for function names specified at tracing time. See Tracing Function Calls for more information.

$ bin64/drrun -t drcachesim -offline -record_function 'fib|1' -- ~/test/fib 5
Estimation of pi is 3.142425985001098
$ bin64/drrun -t drcachesim -simulator_type func_view -indir drmemtrace.*.dir
0x7fc06d2288eb => common.fib!fib(0x5)
    0x7fc06d22888e => common.fib!fib(0x4)
        0x7fc06d22888e => common.fib!fib(0x3)
            0x7fc06d22888e => common.fib!fib(0x2)
                0x7fc06d22888e => common.fib!fib(0x1) => 0x1
                0x7fc06d22889d => common.fib!fib(0x0) => 0x1
            => 0x2
            0x7fc06d22889d => common.fib!fib(0x1) => 0x1
        => 0x3
        0x7fc06d22889d => common.fib!fib(0x2)
            0x7fc06d22888e => common.fib!fib(0x1) => 0x1
            0x7fc06d22889d => common.fib!fib(0x0) => 0x1
        => 0x2
    => 0x5
    0x7fc06d22889d => common.fib!fib(0x3)
        0x7fc06d22888e => common.fib!fib(0x2)
            0x7fc06d22888e => common.fib!fib(0x1) => 0x1
            0x7fc06d22889d => common.fib!fib(0x0) => 0x1
        => 0x2
        0x7fc06d22889d => common.fib!fib(0x1) => 0x1
    => 0x3
=> 0x8
Function view tool results:
Function id=0: common.fib!fib
       15 calls
       15 returns

Cache Line Histogram

The top referenced cache lines are displayed by the histogram tool:

$ bin64/drrun -t drcachesim -simulator_type histogram -- ~/test/pi_estimator
Estimation of pi is 3.142425985001098
---- <application exited with code 0> ----
Cache line histogram tool results:
icache: 1134 unique cache lines
dcache: 3062 unique cache lines
icache top 10
    0x7facdd013780: 30929
    0x7facdb789fc0: 27664
    0x7facdb78a000: 18629
    0x7facdd003e80: 18176
    0x7facdd003500: 11121
    0x7facdd0034c0: 9763
    0x7facdd005940: 8865
    0x7facdd003480: 8277
    0x7facdb789f80: 6660
    0x7facdd003540: 5888
dcache top 10
    0x7ffcc35e7d80: 4088
    0x7ffcc35e7d40: 3497
    0x7ffcc35e7e00: 3478
    0x7ffcc35e7f40: 2919
    0x7ffcc35e7dc0: 2837
    0x7facdbe2e980: 2452
    0x7facdbe2ec80: 2273
    0x7ffcc35e7e80: 2194
    0x7facdb6625c0: 2016
    0x7ffcc35e7e40: 1997

Invariant Checker

The invariant_checker tool performs sanity checks on a trace, focusing on program counter continuity and guarantees around kernel control transfer interruptions. It optionally checks for restricted behavior that technically is legal but is not expected to happen in the target trace, helping to identify tracing problems and suitability for use of a trace for core simulation.

System Call Mix

The system call mix tool counts the frequency of system calls in a trace. It works for both online and offline traces. It uses the dynamorio::drmemtrace::TRACE_MARKER_TYPE_SYSCALL markers that store the system call number. This works only with traces that have these markers; that is, offline traces must have dynamorio::drmemtrace::OFFLINE_FILE_TYPE_SYSCALL_NUMBERS in their file type.

$ bin64/drrun -t drcachesim -indir drmemtrace.ls.*.dir -simulator_type syscall_mix
Syscall mix tool results:
          count : syscall_num
             17 :         9
             16 :         1
              8 :         3
              7 :       262
              6 :       257
              5 :         0
              5 :        10
              3 :        12
              2 :       217
              2 :        16
              2 :        17
              2 :       137
              2 :        21
              1 :       158
              1 :       302
              1 :       334
              1 :       218
              1 :       231
              1 :       318
              1 :        11
              1 :       273