Restrict the capacity of first argument to `append()` to force an allocation.
This is for the slice implementation only.
Signed-off-by: Domantas Jadenkus <djadenkus@gmail.com>
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Restrict the capacity of first argument to `append()` to force an allocation.
This is for the slice implementation only.
Signed-off-by: Domantas Jadenkus <djadenkus@gmail.com>
This function is called very frequently when executing PromQL functions,
and we can do it much more efficiently inside Labels.
In the common case that `__name__` comes first in the labels, we simply
re-point to start at the next label, which is nearly free.
`DropMetricName` is now so cheap I removed the cache - benchmarks show
everything still goes faster.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This reduces bulk and should avoid issues if a fix is made in one file
and not the other.
A few methods now call `Range()` instead of `range`, but nothing
performance-sensitive.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Labels: reduce allocations when creating from TSDB
When reading the WAL, by passing references into the buffer we can avoid
copying strings under `-tags stringlabels`.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* labels: respect Set after Del in Builder (#12322)
The implementations are not symmetric between `Set()` and `Del()`, so
we must be careful. Add tests for this, both in labels and in relabel
where the issue was reported.
Also make the slice implementation consistent re `slices.Contains`.
* Create v2.43.1 with bugfix
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Co-authored-by: Julius Volz <julius.volz@gmail.com>
* labels: respect Set after Del in Builder
The implementations are not symmetric between `Set()` and `Del()`, so
we must be careful. Add tests for this, both in labels and in relabel
where the issue was reported.
Also make the slice implementation consistent re `slices.Contains`.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Wiser coders than myself have come to the conclusion that a `switch`
statement is almost always superior to a statement that includes any
`else if`.
The exceptions that I have found in our codebase are just these two:
* The `if else` is followed by an additional statement before the next
condition (separated by a `;`).
* The whole thing is within a `for` loop and `break` statements are
used. In this case, using `switch` would require tagging the `for`
loop, which probably tips the balance.
Why are `switch` statements more readable?
For one, fewer curly braces. But more importantly, the conditions all
have the same alignment, so the whole thing follows the natural flow
of going down a list of conditions. With `else if`, in contrast, all
conditions but the first are "hidden" behind `} else if `, harder to
spot and (for no good reason) presented differently from the first
condition.
I'm sure the aforemention wise coders can list even more reasons.
In any case, I like it so much that I have found myself recommending
it in code reviews. I would like to make it a habit in our code base,
without making it a hard requirement that we would test on the CI. But
for that, there has to be a role model, so this commit eliminates all
`if else` occurrences, unless it is autogenerated code or fits one of
the exceptions above.
Signed-off-by: beorn7 <beorn@grafana.com>
This is a method used by some downstream projects; it was created to
optimize the implementation in `labels_string.go` but we should have one
for both implementations so the same code works with either.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Deleted labels are remembered, even if they were not in `base` or were
removed from `add`, so `base+add-del` could go negative.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Go spends some time initializing all the elements of these arrays to
zero, so reduce the size from 1024 to 128. This is still much bigger
than we ever expect for a set of labels.
(If someone does have more than 128 labels it will still work, but via
heap allocation.)
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
It took a `Labels` where the memory could be re-used, but in practice
this hardly ever benefitted. Especially after converting `relabel.Process`
to `relabel.ProcessBuilder`.
Comparing the parameter to `nil` was a bug; `EmptyLabels` is not `nil`
so the slice was reallocated multiple times by `append`.
Lastly `Builder.Labels()` now estimates that the final size will depend
on labels added and deleted.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Although we had a different slice, the underlying memory was the same so
any changes meant we could skip some values.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Although we had a different slice, the underlying memory was the same so
any changes meant we could skip some values.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This lets relabelling work on a `Builder` rather than converting to and
from `Labels` on every rule.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
The difference is modest, but we've used `slices.Sort` in lots of other
places so why not here.
name old time/op new time/op delta
Builder 1.04µs ± 3% 0.95µs ± 3% -8.27% (p=0.008 n=5+5)
name old alloc/op new alloc/op delta
Builder 312B ± 0% 288B ± 0% -7.69% (p=0.008 n=5+5)
name old allocs/op new allocs/op delta
Builder 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.008 n=5+5)
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
This commit adds an alternate implementation for `labels.Labels`, behind
a build tag `stringlabels`.
Instead of storing label names and values as individual strings, they
are all concatenated into one string in this format:
[len][name0][len][value0][len][name1][len][value1]...
The lengths are varint encoded so usually a single byte.
The previous `[]string` had 24 bytes of overhead for the slice and 16
for each label name and value; this one has 16 bytes overhead plus 1
for each name and value.
In `ScratchBuilder.Overwrite` and `Labels.Hash` we use an unsafe
conversion from string to byte slice. `Overwrite` is explicitly unsafe,
but for `Hash` this is a pure performance hack.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Instead of passing in a `ScratchBuilder` and `Labels`, just pass the
builder and the caller can extract labels from it. In many cases the
caller didn't use the Labels value anyway.
Now in `Labels.ScratchBuilder` we need a slightly different API: one
to assign what will be the result, instead of overwriting some other
`Labels`. This is safer and easier to reason about.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Without changing the definition of `labels.Labels`, add methods which
enable code using it to work without knowledge of the internals.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
For performance reasons we may use a different implementation of Hash()
in future, so note this so callers can be warned.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Replacing code which assumes the internal structure of `Labels`.
Add a convenience function `EmptyLabels()` which is more efficient than
calling `New()`.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* model/relabel: Add benchmark
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* model/relabel: re-use Builder across relabels
Saves memory allocations.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* labels.Builder: allow re-use of result slice
This reduces memory allocations where the caller has a suitable slice available.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* model/relabel: re-use source values slice
To reduce memory allocations.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Unwind one change causing test failures
Restore original behaviour in PopulateLabels, where we must not overwrite the input set.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* relabel: simplify values optimisation
Use a stack-based array for up to 16 source labels, which will be the
vast majority of cases.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* lint
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Labels: create signature with/without labels
Instead of creating a new Labels slice then converting to signature,
go directly to the signature and save time.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Labels: refactor Builder tests
Have one test with a range of cases, and have them check the final
output rather than checking the internal structure of the Builder.
Also add a couple of cases where the value is "", which should be
interpreted as 'delete'.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
* Labels: add 'Keep' function to Builder
This lets us replace `Labels.WithLabels` with the more general `Builder`.
In `engine.resultMetric()` we can call `Keep()` instead of checking
and calling `Del()`.
Avoid calling `Sort()` in `Builder.Labels()` if we didn't add anything,
so that `Keep()` has the same performance as `WithLabels()`.
Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
We know the max size of our map so we can create it with that information and avoid extra allocations
Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
* labels.Equal benchmark for equal, not equal, and differing lengths
Signed-off-by: Nick Pillitteri <nick.pillitteri@grafana.com>
* Compare equality of label.Label structs directly
Compare the structs using `==` instead of the name and value
of each label. This is functionally equivalent and about ~10%
faster in my testing.
Signed-off-by: Nick Pillitteri <nick.pillitteri@grafana.com>
* Use longer more realistic names and values in benchmark
Signed-off-by: Nick Pillitteri <nick.pillitteri@grafana.com>
This creates a new `model` directory and moves all data-model related
packages over there:
exemplar labels relabel rulefmt textparse timestamp value
All the others are more or less utilities and have been moved to `util`:
gate logging modetimevfs pool runtime
Signed-off-by: beorn7 <beorn@grafana.com>
* Use go1.14 new hash/maphash to hash both RHS and LHS instead of XOR'ing
which has been resulting in hash collisions.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Refactor engine labelset signature generation, just use labels.Labels
instead of hashes.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments; function comments + store result of
lhs.String+rhs.String as key.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Replace all signatureFunc usage with signatureFuncString.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Make optimizations to labels String function and generation of rhs+lhs
as string in resultMetric.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Use separate string functions that don't use strconv just for engine
maps.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Use a byte invalid separator instead of quoting and have a buffer
attached to EvalNodeHelper instead of using a global pool in the labels
package.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address review comments.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Address more review comments, labels has a function that now builds a
byte slice without turning it into a string.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* Use two different non-ascii hex codes as byte separators between labels
and between sets of labels when building bytes of a Labels struct.
Signed-off-by: Callum Styan <callumstyan@gmail.com>
* We only need the 2nd byte invalid sep. at the beginning of a
labels.Bytes
Signed-off-by: Callum Styan <callumstyan@gmail.com>
strings.Compare isn't meant to be used, and this way we save one
comparison which is thus very slightly cheaper.
benchmark old ns/op new ns/op delta
BenchmarkPostingsForMatchers/Head/n="1"-4 236305440 233515705 -1.18%
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
This function is only used in one place to format an error message when
encountering multiple matches on the "one" side of a
one-to-many/many-to-one vector match, which is probably why nobodoy has
noticed this before. The hashing is already done correctly and excludes
the metric name label when using the "ignoring" matching modifier.
Signed-off-by: Julius Volz <julius.volz@gmail.com>
Fixes https://github.com/prometheus/common/issues/36
Move logic handling this into the labels package,
so all the cases are handled in one place and we're
less likely to have this come up again.
Signed-off-by: Brian Brazil <brian.brazil@robustperception.io>
Domantas