Does anyone use Linux perf here, with D symbols demangled?

I'm on Ubuntu 19.10, but I can't get perf to demangle the D symbols.

On Wednesday, 26 February 2020 at 07:20:03 UTC, Arun Chandrasekaran wrote:
> Does anyone use Linux perf here, with D symbols demangled?
>
> I'm on Ubuntu 19.10, but I can't get perf to demangle the D symbols.

I vaguely remember using ddemangle

On 2/26/20 10:20 AM, Arun Chandrasekaran wrote:
> Does anyone use Linux perf here, with D symbols demangled?
> 
> I'm on Ubuntu 19.10, but I can't get perf to demangle the D symbols.

If you use `perf report` then that currently is impossible I guess. But if you use flamegraph for example then ddemangle can help here:
```
git clone https://github.com/brendangregg/FlameGraph.git
perf script | FlameGraph/stackcollapse-perf.pl | FlameGraph/flamegraph.pl | ddemangle > perf.svg
```

but some symbols remain mangled

On Wednesday, 26 February 2020 at 07:20:03 UTC, Arun Chandrasekaran wrote:
> Does anyone use Linux perf here, with D symbols demangled?
>
> I'm on Ubuntu 19.10, but I can't get perf to demangle the D symbols.

For the non interactive version, you can just use `perf report | ddemangle`
As for the interactive version, I don't know. Other coreutils tools have a `--demangle=dlang` option (e.g. `nm`), but perf only have `--demangle` to prevent demangling of symbols:

```
        --demangle        Disable symbol demangling
        --demangle-kernel
                          Enable kernel symbol demangling
```

There's also an `objdump` option which you can set to a shell script that does `objdump --demangle=dlang $*` so you get symbols demangled in the disassembled code, but for the main interface, there doesn't seem to be a way to do it interactively. Perhaps raise the issue upstream?

On Wednesday, 26 February 2020 at 07:20:03 UTC, Arun Chandrasekaran wrote:
> Does anyone use Linux perf here, with D symbols demangled?
>
> I'm on Ubuntu 19.10, but I can't get perf to demangle the D symbols.

This is my sh script for performance monitoring on debian buster using Brendan Greggs flamegraph:

sudo perf record -F 99 -a --call-graph dwarf -- sleep 10
#sudo perf record -F 99 --call-graph dwarf -p 31984
sudo perf script > tree.perf
~/dev/FlameGraph/stackcollapse-perf.pl tree.perf > tree.folded
~/dev/FlameGraph/flamegraph.pl tree.folded > tree_.svg
cat tree_.svg | ./dfilt > tree.svg
firefox tree.svg

This is the source code in dfilt:

import std.ascii : isAlphaNum;
import std.algorithm;
import std.range;
import std.conv : to;
import std.demangle : demangle;
import std.functional : pipe;
import std.stdio;



string translateSymbol(string s)
{
	if (s[0..2] == "_D")
	{
		auto result = demangle(s);
		writefln("%s => %s",s,result);
	}
	return s;
}

string translateGroup(U)(U group)
{
	if ((group[0]))
		return demangle(group[1].to!string);
	else
		return group[1].to!string;
}

auto translateLine(string l)
{
	return l.chunkBy!(a => isAlphaNum(a) || a == '_').map!translateGroup.joiner;
}

void main()
{
    auto result = stdin.byLineCopy
        .map!translateLine
        .joiner("\n").array;
		
	result.copy(stdout.lockingTextWriter);
}


Hope this helps

On Wednesday, 26 February 2020 at 13:21:42 UTC, Alex Burton wrote:
> On Wednesday, 26 February 2020 at 07:20:03 UTC, Arun Chandrasekaran wrote:
>> [...]
>
> This is my sh script for performance monitoring on debian buster using Brendan Greggs flamegraph:
>
> [...]

These work-arounds work to some extent, but gets in the way too often as (I'm just lazy). I will see if I can check with upstream to include ddemangle.

Thanks everyone.