docs: README should mention MacOS support

[nrc]

Whether flamegraph supports MacOS or not, the README should say so.

[mimoo]

it doesn't : (

[jonhoo]

It does support it using dtrace, though I don't know how standard that is on macOS?

[mimoo]

dtrace: system integrity protection is on, some features will not be available
dtrace: failed to initialize dtrace: DTrace requires additional privileges
failed to sample program

[davidrusu]

You'll need to disable SIP on your mac to have dtrace work.

Mentioning this in the readme would be nice, and maybe also with a link to how to disable it:

https://developer.apple.com/library/archive/documentation/Security/Conceptual/System_Integrity_Protection_Guide/ConfiguringSystemIntegrityProtection/ConfiguringSystemIntegrityProtection.html#//apple_ref/doc/uid/TP40016462-CH5-SW1

reboot into recovery mode and run csrutil disable

[benhannel]

I have system integrity protection off, and flamegraph still can't use dtrace:

bens-mbp-4:program bhannel$ csrutil status
System Integrity Protection status: disabled.
bens-mbp-4:program bhannel$ cargo flamegraph --bin=bench
warning: `panic` setting is ignored for `test` profile
    Finished release [optimized] target(s) in 0.02s

WARNING: building without debuginfo. Enable symbol information by adding the following lines to Cargo.toml:

[profile.release]
debug = true

dtrace: failed to initialize dtrace: DTrace requires additional privileges
failed to sample program

[bjorn3]

You need to use sudo.

[benhannel]

Thanks! I was trying sudo su and had issues but just sudo cargo flamegraph --bin=bench works.

[bjorn3]

You can also use cargo flamegraph --sudo --bin=bench to prevent any rustc invocations being performed as root.

[capnfabs]

As at 20 Feb, the above invocation should be cargo flamegraph --root --bin=bench, but I can confirm that it works ✨

[rsqv]

As at 20 Feb, the above invocation should be cargo flamegraph --root --bin=bench, but I can confirm that it works ✨

This should definitely be added to the README!

[djc]

@rsqv would you like to submit a PR? I'd be happy to review it!

[mimoo]

the --sudo flag doesn't work anymore.

EDIT: sorry for bumping, the --root command threw me off as it's usually used to change the root of the workspace or something