LLVM-PROFDATA(1)

📦
version 21.1.8 · 8 versions
, in fedora 44

💖 llvm-profdata — Profile data tool 💖

okay bestie, this is the LLVM manual page for the profile data tool. We are so back.

🌸 NAME 🌸

llvm-profdata — Profile data tool, from the LLVM manual, and yes she is iconic 🫶

✨ SYNOPSIS ✨

The whole vibe is:

llvm-profdata command [args...]

🦋 DESCRIPTION 🦋

The llvm-profdata tool is a small utility for working with profile data files. Small utility, huge slay. No cap.

👑 COMMANDS 👑

The commands are giving:

  • merge
  • show
  • overlap
  • order

🔥 MERGE 🔥

📜 SYNOPSIS 📜

llvm-profdata merge [options] [filename...]

🦋 DESCRIPTION 🦋

llvm-profdata merge takes several profile data files generated by PGO instrumentation and merges them together into a single indexed profile data file. Merging era. 💅

By default profile data is merged without modification. This means that the relative importance of each input file is proportional to the number of samples or counts it contains. In general, the input from a longer training run will be interpreted as relatively more important than a shorter run. Depending on the nature of the training runs it may be useful to adjust the weight given to each input file by using the -weighted-input option.

Profiles passed in via -weighted-input, -input-files, or via positional arguments are processed once for each time they are seen.

✨ OPTIONS ✨

  • --help — Print a summary of command line options. Short, sweet, helpful.
  • --output=<output>, -o — Specify the output file name. Output cannot be - as the resulting indexed profile data can't be written to standard output. Like, literally cannot.
  • --weighted-input=<weight,filename> — Specify an input file name along with a weight. The profile counts of the supplied filename will be scaled (multiplied) by the supplied weight, where weight is a decimal integer >= 1. Input files specified without using this option are assigned a default weight of 1. Examples are shown below.
  • --input-files=<path>, -f — Specify a file which contains a list of files to merge. The entries in this file are newline-separated. Lines starting with # are skipped. Entries may be of the form <filename> or <weight>,<filename>.
  • --remapping-file=<path>, -r — Specify a file which contains a remapping from symbol names in the input profile to the symbol names that should be used in the output profile. The file should consist of lines of the form <input-symbol> <output-symbol>. Blank lines and lines starting with # are skipped.

The llvm-cxxmap <> tool can be used to generate the symbol remapping file. iykyk

  • --instr (default) — Specify that the input profile is an instrumentation-based profile.
  • --sample — Specify that the input profile is a sample-based profile.

The format of the generated file can be generated in one of three ways:

  • --binary (default) — Emit the profile using a binary encoding. For instrumentation-based profile the output format is the indexed binary format.
  • --extbinary — Emit the profile using an extensible binary encoding. This option can only be used with sample-based profile. The extensible binary encoding can be more compact with compression enabled and can be loaded faster than the default binary encoding.
  • --text — Emit the profile in text mode. This option can also be used with both sample-based and instrumentation-based profile. When this option is used the profile will be dumped in the text format that is parsable by the profile reader.
  • --gcc — Emit the profile using GCC's gcov format (Not yet supported).
  • --sparse[=true|false] — Do not emit function records with 0 execution count. Can only be used in conjunction with -instr. Defaults to false, since it can inhibit compiler optimization during PGO. Careful, bestie.
  • --num-threads=<N>, -j — Use N threads to perform profile merging. When N=0, llvm-profdata auto-detects an appropriate number of threads to use. This is the default. Multithreading moment.
  • --failure-mode=[any|all] — Set the failure mode. There are two options: 'any' causes the merge command to fail if any profiles are invalid, and 'all' causes the merge command to fail only if all profiles are invalid. If 'all' is set, information from any invalid profiles is excluded from the final merged product. The default failure mode is 'any'.
  • --prof-sym-list=<path> — Specify a file which contains a list of symbols to generate profile symbol list in the profile. This option can only be used with sample-based profile in extbinary format. The entries in this file are newline-separated.
  • --compress-all-sections=[true|false] — Compress all sections when writing the profile. This option can only be used with sample-based profile in extbinary format.
  • --use-md5=[true|false] — Use MD5 to represent string in name table when writing the profile. This option can only be used with sample-based profile in extbinary format.
  • --gen-partial-profile=[true|false] — Mark the profile to be a partial profile which only provides partial profile coverage for the optimized target. This option can only be used with sample-based profile in extbinary format.
  • --split-layout=[true|false] — Split the profile data section to two with one containing sample profiles with inlined functions and the other not. This option can only be used with sample-based profile in extbinary format.
  • --convert-sample-profile-layout=[nest|flat] — Convert the merged profile into a profile with a new layout. Supported layout are nest (Nested profile, the input should be CS flat profile) and flat (Profile with nested inlinees flattened out).
  • --supplement-instr-with-sample=<file> — Supplement an instrumentation profile with sample profile. The sample profile is the input of the flag. Output will be in instrumentation format (only works with -instr).
  • --zero-counter-threshold=<float> — For the function which is cold in instr profile but hot in sample profile, if the ratio of the number of zero counters divided by the total number of counters is above the threshold, the profile of the function will be regarded as being harmful for performance and will be dropped.
  • --instr-prof-cold-threshold=<int> — User specified cold threshold for instr profile which will override the cold threshold got from profile summary.
  • --suppl-min-size-threshold=<int> — If the size of a function is smaller than the threshold, assume it can be inlined by PGO early inliner and it will not be adjusted based on sample profile.
  • --debug-info=<path> — Specify the executable or .dSYM that contains debug info for the raw profile. When --debug-info-correlate or --profile-correlate=debug-info was used for instrumentation, use this option to correlate the raw profile.
  • --binary-file=<path> — Specify the executable that contains profile data and profile name sections for the raw profile. When -profile-correlate=binary was used for instrumentation, use this option to correlate the raw profile.
  • --debuginfod — Use debuginfod to find the associated executables that contain profile data and name sections for the raw profiles to correlate them. When -profile-correlate=binary was used for instrumentation, this option can be used for correlation.
  • --debug-file-directory=<dir> — Use provided local directories to search for executables that contain profile data and name sections for the raw profiles to correlate them. When -profile-correlate=binary was used for instrumentation, this option can be used for correlation.
  • --correlate=<kind> — Specify the correlation kind (debug_info or binary) to use when -debuginfod or -debug-file-directory=<dir> option is provided.
  • --temporal-profile-trace-reservoir-size — The maximum number of temporal profile traces to be stored in the output profile. If more traces are added, we will use reservoir sampling to select which traces to keep. Note that changing this value between different merge invocations on the same indexed profile could result in sample bias. The default value is 100.
  • --temporal-profile-max-trace-length — The maximum number of functions in a single temporal profile trace. Longer traces will be truncated. The default value is 1000.
  • --function=<string> — Only keep functions matching the regex in the output, all others are erased from the profile.
  • --no-function=<string> — Remove functions matching the regex from the profile. If both --function and --no-function are specified and a function matches both, it is removed.

🌈 EXAMPLES 🌈

💫 Basic Usage 💫

Merge three profiles:

llvm-profdata merge foo.profdata bar.profdata baz.profdata -output merged.profdata

🎀 Weighted Input 🎀

The input file foo.profdata is especially important, multiply its counts by 10:

llvm-profdata merge --weighted-input=10,foo.profdata bar.profdata baz.profdata --output merged.profdata

Exactly equivalent to the previous invocation (explicit form; useful for programmatic invocation):

llvm-profdata merge --weighted-input=10,foo.profdata --weighted-input=1,bar.profdata --weighted-input=1,baz.profdata --output merged.profdata

🌟 SHOW 🌟

✨ SYNOPSIS ✨

llvm-profdata show [options] [filename]

💅 DESCRIPTION 💅

So llvm-profdata show takes a profile data file and, like, displays the info about the profile counters for that file — and for any function(s) you specify 💖. It's the "let me see what's in here" command, no cap.

And if you omit filename, or if you just pass -? Then llvm-profdata show reads its input from standard input. Iconic, honestly.

🎀 OPTIONS 🎀

  • --all-functions — prints the details for every single function. All of them. No filtering, bestie, we're seeing everybody 🫶
  • --binary-ids — prints the embedded binary IDs that are chillin' inside a profile.
  • --counts — prints out the counter values for the functions being displayed.
  • --show-format=<text|json|yaml> — emits the output in whichever format you picked, if the provided profile type supports it. So text, json, or yaml — vibes your choice ✨
  • --function=<string> — prints the details for a function when that function's name contains the given string. Substring match, iykyk.
  • --help — prints a summary of command line options. The classic.
  • --output=<output>, -o — specifies the output file name. If output is -, or if you just don't specify it at all, then the output goes to standard output 💫
  • --instr (this is the default!) — says "hey, the input profile is an instrumentation-based profile."
  • --text — tells the profile dumper to show the profile counts in the text format of the instrumentation-based profile data representation. By default the profile info gets dumped in a more human readable form (also in text!) with annotations. Cute either way 🌸
  • --topn=<n> — tells the profile dumper to show the top n functions with the hottest basic blocks in the summary section 🔥 By default, the topn functions are not dumped.
  • --sample — says the input profile is a sample-based profile.
  • --memop-sizes — shows the profiled sizes of the memory intrinsic calls for the functions being shown.
  • --value-cutoff=<n> — shows only those functions whose max count values are greater than or equal to n. By default, the value-cutoff is set to 0.
  • --list-below-cutoff — outputs only the names of functions whose max count value is below the cutoff value. Just the names bestie, that's it.
  • --profile-version — prints the profile version.
  • --showcs — only shows context sensitive profile counts. The default is to filter all context sensitive profile counts 🙈
  • --show-prof-sym-list=[true|false] — shows the profile symbol list if it exists in the profile. Heads up: this option is only meaningful for sample-based profile in extbinary format.
  • --show-sec-info-only=[true|false] — shows basic info about each section in the profile. Same deal — only meaningful for sample-based profile in extbinary format.
  • --debug-info=<path> — specifies the executable or .dSYM that contains debug info for the raw profile 🐛 When --debug-info-correlate or --profile-correlate=debug-info was used for instrumentation, use this option to show the correlated functions from the raw profile.
  • --covered — shows only the functions that have actually been executed, i.e. functions with non-zero counts. Main character functions only 👑

🦋 OVERLAP 🦋

✨ SYNOPSIS ✨

llvm-profdata overlap [options] [base profile file] [test profile file]

💅 DESCRIPTION 💅

llvm-profdata overlap takes two profile data files and displays the overlap of counter distribution — both between the whole files and between any of the specified functions 🫶

Okay so in this command, overlap is defined like this. Suppose the base profile file has the following counts: {c1_1, c1_2, ..., c1_n, c1_u_1, c2_u_2, ..., c2_u_s}, and the test profile file has {c2_1, c2_2, ..., c2_n, c2_v_1, c2_v_2, ..., c2_v_t}. Here c{1|2}_i (i = 1 .. n) are the matched counters, and c1_u_i (i = 1 .. s) and c2_v_i (i = 1 .. v) are the unmatched counters (or, like, counters that only exist in) the base profile file and the test profile file respectively. Let sum_1 = c1_1 + c1_2 + ... + c1_n + c1_u_1 + c2_u_2 + ... + c2_u_s, and sum_2 = c2_1 + c2_2 + ... + c2_n + c2_v_1 + c2_v_2 + ... + c2_v_t. Then overlap = min(c1_1/sum_1, c2_1/sum_2) + min(c1_2/sum_1, c2_2/sum_2) + ... + min(c1_n/sum_1, c2_n/sum_2).

The result overlap distribution is a percentage number, ranging from 0.0% to 100.0% — where 0.0% means there's no overlap and 100.0% means a perfect overlap 💯

Here's an example, fr: if the base profile file has counts of {400, 600}, and the test profile file has matched counts of {60000, 40000}, the overlap is 80%. Slay.

🎀 OPTIONS 🎀

  • --function=<string> — prints details for a function if the function's name contains the given string.
  • --help — prints a summary of command line options.
  • --output=<output>, -o — specifies the output file name. If output is -, or it isn't specified, then the output heads to standard output 💫
  • --value-cutoff=<n> — shows only those functions whose max count values are greater than or equal to n. By default, the value-cutoff is set to the max of unsigned long long. Big number energy.
  • --cs — only shows overlap for the context sensitive profile counts. The default is to show non-context sensitive profile counts.

🌈 ORDER 🌈

✨ SYNOPSIS ✨

llvm-profdata order [options] [filename]

💅 DESCRIPTION 💅

llvm-profdata order uses temporal profiling traces from a profile and finds a function order that reduces the number of page faults for those traces 😭✨ This output can be passed directly to lld via --symbol-ordering-file= for ELF, or -order-file for Mach-O. And if the traces found in the profile are actually representative of the real world, then this order should improve startup performance. Obsessed with a performance win, honestly.

🎀 OPTIONS 🎀

  • --help — prints a summary of command line options.
  • --output=<output>, -o — specifies the output file name. If output is -, or it isn't specified, then the output is sent to standard output 💖

⭐ EXIT STATUS ⭐

llvm-profdata returns 1 if the command is omitted or is invalid, if it can't read input files, or if there's a mismatch between their data. So if you see a 1, something's giving "not it" 💀

👑 Author 👑

Maintained by the LLVM Team (https://llvm.org/). Love that for them 🫶

2003-2026, LLVM Project

And that's a wrap bestie!! 🦋✨ This whole page is brought to you by the LLVM Team, dated 2026-05-15, and it's page 21 of the LLVM-PROFDATA(1) manual — go forth and profile responsibly 💅💖

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