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When I wanted to run perf under WSL, I met the follow question:

WARNING: perf not found for kernel 4.4.0-18362

You may need to install the following packages for this specific kernel:

linux-tools-4.4.0-18362-Microsoft

linux-cloud-tools-4.4.0-18362-Microsoft

You may also want to install one of the following packages to keep up to date:

linux-tools-Microsoft

linux-cloud-tools-Microsoft

But I can't find packages called linux-tools-4.4.0-18362-Microsoft or linux-cloud-tools-4.4.0-18362-Microsoft. I guess the package names are generated automatically.

I also tried to use perf in docker container. However, docker container use the same kernel as the hosts.

Is there any method to run perf under WSL?

I heard that perf can be used in WSL2. But after I upgraded to WSL2, it shows the similar error message:

WARNING: perf not found for kernel 4.19.84-microsoft

You may need to install the following packages for this specific kernel:

linux-tools-4.19.84-microsoft-standard

linux-cloud-tools-4.19.84-microsoft-standard

You may also want to install one of the following packages to keep up to date:

linux-tools-standard

linux-cloud-tools-standard
yodahaji
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    In WSL2, perf can be used – Biswapriyo Feb 16 '20 at 20:53
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    @Biswapriyo Hi, I upgraded wsl1 to wsl2. However, it shows the semilar error message in wsl1: – yodahaji Feb 18 '20 at 07:59
  • Did you install any `linux*-tools*` package(s) that you can see in `aptitute` or whatever package-manager you use? Your 2nd error message even lists some package names to install. – Peter Cordes Feb 18 '20 at 08:32
  • @PeterCordes Hi, I searched for these packages but found nothing. I guess these names are generated automatically. I found the correct answer below. – yodahaji Feb 18 '20 at 09:13
  • It didn't say that in your question so it seemed like there'd be some hope that the distro would package `linux-tools` since the kernel supports `perf`. But apparently not. Silly Microsoft :/ – Peter Cordes Feb 18 '20 at 09:32

5 Answers5

73

WARNING: perf not found for kernel 4.19.84-microsoft

Because WSL2 uses custom Linux kernel. Its source code can be found here microsoft/WSL2-Linux-Kernel. We have to compile perf tools from it.

Procedure

  • Install required build packages. If you are using Ubuntu in WSL2 this is the required command:
sudo apt install build-essential flex bison libssl-dev libelf-dev
  • Clone the WSL2 Linux kernel repository:
git clone --depth=1 https://github.com/microsoft/WSL2-Linux-Kernel.git
  • Go to perf folder and compile it:
cd WSL2-Linux-Kernel/tools/perf
make

perf executable file will be in that folder.

Community
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Biswapriyo
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    Perf tool sources have standalone version at https://mirrors.edge.kernel.org/pub/linux/kernel/tools/perf/ which is easier to use than doing full linux kernel git checkout or download. This site have perf for several recent versions of upstream linux kernel; they should work for any kernel. Or you can try to generate same targz file from WSL2 git with `make perf-targz-src-pkg`. Also: did you check the generated perf executable - what works and what does not; what is in `perf list`, what says perf stat for simple "echo 1", are there hardware events? – osgx Feb 22 '20 at 08:04
  • @osgx I didn't check every options but `./perf stat` works as usual. – Biswapriyo Feb 22 '20 at 08:52
  • Make sure you have WSL 2 installed other wise you will get `perf_event_open(..., 0) failed unexpectedly with error 22 (Invalid argument) ` as described here: https://github.com/microsoft/WSL/issues/329#issuecomment-564454956 – joseph Mar 03 '21 at 00:43
  • I'm getting this:- Error: Unable to find debugfs/tracefs Hint: Was your kernel compiled with debugfs/tracefs support? Hint: Is the debugfs/tracefs filesystem mounted? Hint: Try 'sudo mount -t debugfs nodev /sys/kernel/debug' rebroad@J3PMPJP:~/bin$ sudo mount -t debugfs nodev /sys/kernel/debug mount: /sys/kernel/debug: unknown filesystem type 'debugfs'. – Rebroad May 03 '21 at 14:31
  • hello @Biswapriyo , can you help me about an issue. I have done all of these, but i get this msg in the perf folder: WARNING: perf not found for kernel 5.10.16.3-microsoft – codertryer Nov 30 '21 at 19:53
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    I succeed too run `perf`, but only generic event are available for me. No hardware events (like the number of AVX arithmetic operation or the amount of read/written MiB from/to RAM on Skylake). I used the version 5.10. Interestingly, `perf top` does not see Windows application. – Jérôme Richard Jan 31 '22 at 23:54
  • @JérômeRichard: When you say "generic events" worked, do you mean hardware PMU events like `cycles` and `instructions`, but not uarch-specific stuff like `mem_inst_retired.any`? Or do you only mean kernel software events like `task-clock`, `page-faults`, and `context-switches`, but not `instructions`? A recent answer installed a non-WLS2 version of `perf` and found no HW events were working. – Peter Cordes Nov 08 '22 at 13:40
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    @PeterCordes I should have said system events rather than generic events. `perf stat` reports: task-clock, context-switches, cpu-migrations, page-faults. But the others like instructions or cycles are unsupported. – Jérôme Richard Nov 08 '22 at 15:31
  • @JérômeRichard: Ok, that makes more sense, I'd expect either no PMU events or all of them. With none being most likely since it runs in a VM, thus the hypervisor would need to virtualize the PMU for it to work. – Peter Cordes Nov 08 '22 at 15:33
35

You can install linux-tools-generic.

apt install linux-tools-generic

Then run perf using the install path /usr/lib/linux-tools/<linux-version>-generic/perf.

Some tools, like flamegraph, will use environment variable PERF as the perf path.

PERF=/usr/lib/linux-tools/<linux-version>-generic/perf flamegraph -- my_program
JamesThomasMoon
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Gloit
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  • Thanks for this answer. When I was typing perf in the cli it was using `/usr/bin/perf` instead of `/usr/lib/linux-tools/5.4.0-104-generic/perf` – Orion Mar 15 '22 at 15:03
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The accepted answer works. However, some features are missing.

In order to get useful and demangled information, I had to install the following libs and then run make again.

  • libbabeltrace-dev
  • libunwind-dev
  • libdw-dev
  • binutils-dev
  • libiberty-dev

I'm not sure if all of them are necessary. However, those are adequate for cargo-flamegraph (my usecase) to work.

cwhakes
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  • This does not really answer the question. If you have a different question, you can ask it by clicking [Ask Question](https://stackoverflow.com/questions/ask). To get notified when this question gets new answers, you can [follow this question](https://meta.stackexchange.com/q/345661). Once you have enough [reputation](https://stackoverflow.com/help/whats-reputation), you can also [add a bounty](https://stackoverflow.com/help/privileges/set-bounties) to draw more attention to this question. - [From Review](/review/late-answers/31250818) – Kerel Mar 14 '22 at 10:34
  • This is actually a really good hint. – scigor Apr 12 '22 at 18:43
  • This is helpful. thanks. I also had to install `libssl-dev` to enable the `libcrypto` requirement. – Frederic Jul 22 '22 at 19:31
  • Here's a bigger list: https://gist.github.com/LoganDark/8f9ba939bbe4b73d057ceee46b07e20f – nirvana-msu Feb 14 '23 at 22:14
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You could install some generic version of perf, rather than the WSL2 version, like:

sudo apt install linux-tools-5.4.0-126-generic linux-tools-common

And then when you run perf, it will error out, like:

$ perf
WARNING: perf not found for kernel 5.10.16.3-microsoft

  You may need to install the following packages for this specific kernel:
    linux-tools-5.10.16.3-microsoft-standard-WSL2
    linux-cloud-tools-5.10.16.3-microsoft-standard-WSL2

This is because script /usr/bin/perf always trying to get the perf binary from uname -r

$ grep uname `which perf`
full_version=`uname -r`

We could replace /usr/bin/perf with the actual perf :

mv /usr/bin/perf /usr/bin/perf.bk && ln -s /usr/lib/linux-tools/5.4.0-126-generic/perf /usr/bin/perf

and then:

$ perf stat ls 1>/dev/null

 Performance counter stats for 'ls':

              1.79 msec task-clock:u              #    0.827 CPUs utilized
                 0      context-switches:u        #    0.000 K/sec
                 0      cpu-migrations:u          #    0.000 K/sec
               112      page-faults:u             #    0.063 M/sec
   <not supported>      cycles:u
   <not supported>      instructions:u
   <not supported>      branches:u
   <not supported>      branch-misses:u

       0.002158900 seconds time elapsed

       0.002182000 seconds user
       0.000000000 seconds sys

I think it is expected the hardware/cache counters are not available on WSL2

Baiyan Huang
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    WSL2 runs inside a VM. For HW PMU events to work, the VM + hypervisor would need to support it, so it doesn't let you profile stuff outside of guest VM. (And potentially even get last-branch-record tracing). Last I read, there was some work happening to make KVM support PMU access for Linux-on-Linux virtualization, but IDK if that ever got completed. And clearly WSL2 doesn't do it. – Peter Cordes Nov 08 '22 at 13:34
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    This is exactly the kind of thing I get now on my machine too. Thank you for clarifying this long standing issue. This is sad most events do not work since it makes `perf` nearly useless in WSL... – Jérôme Richard Nov 08 '22 at 15:35
  • This is the only way I could get Hotspot to work on WSL2. – Herne Jun 29 '23 at 13:27
3

If you follow the accepted answer, make sure you read the complains the make command prints at the start, as it might be missing some headers and disables functionality.

For me it disabled tui, gtk and demangling to name a few features.

Jakob Ledermann
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    So which specific packages did you have to install to satisfy those optional dependencies and enable those features? That would make this answer more useful to future readers. – Peter Cordes Oct 17 '20 at 13:07