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Tweaks for datadog compatibility #74

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Tweaks for datadog compatibility #74

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77a8653
try to make compatible with DD
vilterp Feb 3, 2022
285a963
guard lines from being -1
vilterp Oct 21, 2022
5795cd4
allocs: guard against -1
vilterp Oct 21, 2022
75cf270
update period
vilterp Oct 21, 2022
fbb81b5
add (bogus) CPU time sample time to flamegraph profile
vilterp Oct 25, 2022
aa0f960
add module name
vilterp Oct 27, 2022
785f7c1
comment
vilterp Oct 28, 2022
0ece3ea
use existing sampling_delay_ns variable
vilterp Oct 28, 2022
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10 changes: 5 additions & 5 deletions src/Allocs.jl
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Original file line number Diff line number Diff line change
Expand Up @@ -43,7 +43,7 @@ function pprof(alloc_profile::Profile.Allocs.AllocResults = Profile.Allocs.fetch
# Allocs-specific arguments:
frame_for_type::Bool = true,
)
period = UInt64(0x1)
period = sum(alloc.size for alloc in alloc_profile.allocs, init=0)
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🤔 this seems weird.. Isn't this supposed to basically represent how much whatever does one sample represent?

So for a CPU profile, this would be like how much time in between samples? So for an allocation profile, it should be 1 allocation per sample, right?

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Hm yeah I was misunderstanding this.

Looking at the proto, it says "The number of events between sampled occurrences": https://github.com/google/pprof/blob/131d412537eacd9973045c73835c3ac6ed696765/proto/profile.proto#L85-L86

So I guess it's basically supposed to be the sample interval? E.g. "every 1000th alloc" would be 1000?


@assert !isempty(basename(out)) "`out=` must specify a file path to write to. Got unexpected: '$out'"
if !endswith(out, ".pb.gz")
Expand Down Expand Up @@ -72,10 +72,10 @@ function pprof(alloc_profile::Profile.Allocs.AllocResults = Profile.Allocs.fetch
samples = Vector{Sample}()

sample_type = ValueType[
ValueType!("allocs", "count"), # Mandatory
ValueType!("size", "bytes")
ValueType!("alloc_objects", "count"), # Mandatory
ValueType!("alloc_space", "bytes")
]
period_type = ValueType!("heap", "bytes")
period_type = ValueType!("alloc_space", "bytes")
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oh maybe the period_type should actually be (alloc_objects", "count")? then maybe you could keep the period = 0x01?

drop_frames = isnothing(drop_frames) ? 0 : enter!(drop_frames)
keep_frames = isnothing(keep_frames) ? 0 : enter!(keep_frames)

Expand Down Expand Up @@ -136,7 +136,7 @@ function pprof(alloc_profile::Profile.Allocs.AllocResults = Profile.Allocs.fetch

push!(
locations,
Location(;id = loc_id, line=[Line(function_id, line_number)])
Location(;id = loc_id, line=[Line(function_id, line_number > 0 ? line_number : 1)])
)

return loc_id
Expand Down
13 changes: 8 additions & 5 deletions src/PProf.jl
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Expand Up @@ -140,8 +140,8 @@ function pprof(data::Union{Nothing, Vector{UInt}} = nothing,
samples = Vector{Sample}()

sample_type = [
ValueType!("events", "count"), # Mandatory
ValueType!("stack_depth", "count")
ValueType!("events", "count"), # Mandatory
ValueType!("cpu", "nanoseconds")
Comment on lines -143 to +144
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can we still emit stack-depth values, or does even their presence break the datadog viewer?

I'm fine to drop them though; i don't think they really added much, and they're just there because Valentin and i were trying to understand how the sample_types worked, i think

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I'm not sure if they break the DD viewer… I'm not sure why you'd need them though, since each sample itself is a full stack, so the depth information is already there

]

period_type = ValueType!("cpu", "nanoseconds")
Expand All @@ -163,7 +163,7 @@ function pprof(data::Union{Nothing, Vector{UInt}} = nothing,
# End of sample
value = [
1, # events
length(location_id), # stack_depth
60000000 # CPU ns
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what does this mean?

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Hm yeah, I think I found I needed to put some number here to get it to show up in DD, but this is just a bogus value. Not sure what it's supposed to be… Maybe it's supposed to correspond to the sample period? i.e. if you're taking a stack sample every 100ms, this is supposed to be 100ms (in ns)?

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ah, yes, that's right. i think that is exactly what it's supposed to be. it's supposed to be the value matching the value type:

        ValueType!("cpu", "nanoseconds")

👍

🤔 i think you should be able to ask Profile what it's current sample rate is, so that this can be an accurate number.

help?> Profile.init()
  init(; n::Integer, delay::Real)

  Configure the delay between backtraces (measured in seconds), and the number n of instruction pointers that may be stored per thread. Each instruction
  pointer corresponds to a single line of code; backtraces generally consist of a long list of instruction pointers. Note that 6 spaces for instruction
  pointers per backtrace are used to store metadata and two NULL end markers. Current settings can be obtained by calling this function with no arguments,
  and each can be set independently using keywords or in the order (n, delay).

  │ Julia 1.8
  │
  │  As of Julia 1.8, this function allocates space for n instruction pointers per thread being profiled. Previously this was n total.

julia> Profile.init()
(10000000, 0.001)

julia> Profile.init()[2]
0.001

]
push!(samples, Sample(;location_id, value))
location_id = Vector{eltype(data)}()
Expand Down Expand Up @@ -200,7 +200,8 @@ function pprof(data::Union{Nothing, Vector{UInt}} = nothing,

# Use a unique function id for the frame:
func_id = method_instance_id(frame)
push!(location.line, Line(function_id = func_id, line = frame.line))
line_struct = Line(function_id = func_id, line = frame.line > 0 ? frame.line : 1)
push!(location.line, line_struct)

# Known function
func_id in seen_funcs && continue
Expand All @@ -216,7 +217,9 @@ function pprof(data::Union{Nothing, Vector{UInt}} = nothing,
file = string(meth.file)
io = IOBuffer()
Base.show_tuple_as_call(io, meth.name, linfo.specTypes)
full_name_with_args = _escape_name_for_pprof(String(take!(io)))
call_str = String(take!(io))
# add module name as well
full_name_with_args = _escape_name_for_pprof("$(meth.module).$call_str")
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adding the module name here should be the only user-visible change in this PR — it's pretty essential to get frames to show up right in DD since it essentially does

package, func = split(name, "."; limit=2)

e.g. for this one:
image

Without the module name it would parse as

  • package: DatadogProfileUploader.profile_and_upload(DatadogProfileUploader
  • func: DDConfig, typeof(myfunc))

If people don't want the behavior to change though, I could put this behind an option.

start_line = convert(Int64, meth.line)
else
# frame.linfo either nothing or CodeInfo, either way fallback
Expand Down
4 changes: 3 additions & 1 deletion src/flamegraphs.jl
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Expand Up @@ -85,6 +85,7 @@ function pprof(fg::Node{NodeData},

sample_type = [
ValueType!("events", "count"), # Mandatory
ValueType!("cpu", "nanoseconds"),
]

period_type = ValueType!("cpu", "nanoseconds")
Expand Down Expand Up @@ -176,7 +177,8 @@ function pprof(fg::Node{NodeData},
end

value = [
length(span), # Number of samples in this frame.
1, # Number of samples in this frame.
60000000, # CPU ns (TODO: real number)
]
push!(samples, Sample(;location_id, value))

Expand Down