> ## Documentation Index
> Fetch the complete documentation index at: https://sdk.cerebras.ai/llms.txt
> Use this file to discover all available pages before exploring further.
# Release Notes
> Review the cumulative release notes for the Cerebras SDK, including new language features, bug fixes, and breaking changes for each version.
## Version 2.10.0
Released 15 March 2026
The SDK version numbering scheme has been updated to match the Cerebras ML
Software release numbering scheme. SDK 2.10 is the SDK version following
1.4.0, and has been tested for functionality with the Cerebras Wafer-Scale
Cluster appliance running Cerebras ML Software 2.10.
### New Features and Enhancements
* CSL language and compiler enhancements:
* Introduces `anyopaque` type, representing a value whose size and
representation is unknown. This is mostly useful to describe type-erased
pointers: `*anyopaque` is analogous to C's `void*`.
* Introduces arbitrary-width integers. `iN` and `uN` describe a signed or
unsigned integer of `N` bits, where `N` is any nonnegative integer, for
example `u3`, `i4`, `u1`, `i0`, and `u128`. Only integer types with bit
widths of 16 or 32 are ABI-sized. Non-ABI-sized integer types cannot be
used as task parameters, and certain hardware-specific operations, such as
DSD builtins, may require ABI-sized types.
* Introduces `packed struct`. Fields are arranged as a sequence of bits with
no gaps in between. All fields must have defined bit width. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
const some_struct = packed struct {
x: i16,
y: f32,
};
```
* Introduces union types. Untagged unions, analogous to `union` in C, are
supported. Unions may be `packed`, analogous to structs. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
const my_union = packed union {
full : u16,
bits: packed struct {
low: u8,
high: u8,
}
};
```
* Introduces integer and float widening coercions. Coercions among fixed-width
integer types are now supported if the destination type can represent all
possible values of the source type. Likewise for fixed-width float types.
For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
var medium: i16 = 42;
var large: i32 = medium; // OK: i16 can be widened to i32
var small: i8 = medium; // ERROR: i8 cannot represent all i16 values
```
* Introduces coercion of anonymous structs to named struct types. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
const Point = struct {
x: i32,
y: i32,
};
var p: Point = .{.x = 0, .y = 0};
```
* Introduces `*T` to `*[1]T` coercion and `*[N]T` to `[*]T` in peer type
resolution. The type `*T` will now automatically coerce to `*[1]T`, and the
type `*[N]T` will now automatically coerce to `[*]T`.
* Introduces `sr` type representing stride registers, and the `@get_sr`
builtin.
* Introduces `@load_to_dsr_xdsr_sr` builtin, used to load `mem4d_dsd` values
to explicit DSRs, XDSRs, and SRs. `@load_to_dsr` with just a `mem4d_dsd` is
no longer allowed; an XDSR and SR must also be allocated using
`@load_to_dsr_xdsr_sr`. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
const dsr = @get_dsr(dsr_dest, 0);
const xdsr = @get_xdsr(1);
const sr1 = @get_sr(0);
const sr2 = @get_sr(1);
const sr3 = @get_sr(2);
var dsd: mem4d_dsd;
task foo() void {
@load_to_dsr_xdsr_sr(dsr, xdsr, .{sr1, sr2, sr3}, dsd);
}
```
* Introduces FIFO full and empty actions via new `.full_action` (WSE-3 only)
and `.empty_action` fields of the `@allocate_fifo` config struct. These are
actions taken when a push occurs on a full FIFO or a pop occurs from an
empty FIFO, respectively. Accepts options `test_or_suspend`, `terminate`,
`suspend` (WSE-3 only), and `fault` (WSE-3 only). If omitted,
`test_or_suspend` is the default. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
var fifo_buffer = @zeros([32]i16);
const fifo = @allocate_fifo(
fifo_buffer,
.{ .empty_action = .{ .terminate = true },
.full_action = .{ .fault = true } }
);
```
* Introduces task rotation via `@bind_rotating_tasks`. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
const iq = @get_input_queue(0);
const main_id = @get_data_task_id(iq);
task main(data: u32) void {}
task alt() void {}
comptime {
@bind_rotating_tasks(main, alt, main_id, .{.limit = 10});
@initialize_queue(iq, .{.color = c});
@set_control_task_table();
}
```
* Introduces `src0` DSRs as operands of 1-source builtins on WSE-3.
* Introduces support for additional DSD builtin operand combinations on
WSE-3, including `dsr_src0, scalar, dsr_src0`. Additionally, removes the
restriction that `dsr_dest` and `dsr_src0` operands must have the same
number.
* DSR, XDSR, and SR values now support `==` and `!=` comparison. `@get_int`
now supports DSR, XDSR, and SR values.
* `==` and `!=` can now compare `type`. The `@is_same_type` builtin is now
deprecated.
* DSD builtins are now restricted to no more than one `fabin_dsd` operand on
WSE-3, properly reflecting the WSE-3 architectural restriction.
* Introduces dense mode support for queues on WSE-3. See
[@initialize\_queue](/csl/language/builtins#@initialize_queue).
* Introduces support for `circbuf_dsd`. Currently only supported at comptime
and must be manually loaded to DSR+XDSR using `@load_to_dsr_xdsr`.
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
const circbuf = @get_dsd(circbuf_dsd, .{.base_address = &B,
.extent = A_size,
.wraparound = 5});
const src1 = @get_dsr(dsr_src1, 2);
const xdsr_id = @get_xdsr(3);
comptime {
@load_to_dsr_xdsr(src1, xdsr_id, circbuf);
}
```
Wraparound can be inferred from size of `base_address` if it is an array.
* Introduces support for `linksection` on functions. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
export fn has_special_section() linksection("dcache_sect") void {
gv = 42;
}
```
* Changed default SIMD setting on WSE-2 to `simd_32`. Changed behavior of
SIMD settings on WSE-3: the valid options are now `simd_off` and
`simd_max` (default).
* Trailing comma is now allowed in enum members.
* Change to export compatibility of integers and enums: only export
compatible when ABI-sized (16 or 32 bits). Removes export compatibility for
`i8`, `u8`, `i64`, `u64`.
* Default `--max-inlined-iterations` limit is increased.
* Improved pointer representation consistency: values of pointer type are now
always encoded as byte addresses.
* CSL library enhancements:
* Introduces `` library, providing utility functions `lo16`,
`hi16`, `lo32`, and `hi32`.
* Introduces `` library, providing `comptime_int_to_string` and `fmt`
functions.
* Introduces `` library, providing type introspection functions such as
`is_unsigned_int`, `is_signed_int`, `is_float`, `is_numeric`,
`word_size_of`, `byte_size_of`, `bit_size_of`, `is_dsd`, `is_dsr`, and
more.
* Introduces `math.subsat` for saturating subtraction, with `f16`, `f32`, and
generic variants.
* Introduces `tile_config.filters` functions for half-wavelets. Only
supported on WSE-3.
* `SdkRuntime` host runtime enhancements:
* Introduces `cslc_prefix` option in `SdkLayout`.
* Introduces `f16_type` option in `SdkLayout.compile` to specify the 16-bit
floating point format (`F16`, `BF16`, or `CB16`).
* Introduces `libs` option in `SdkLayout.compile` to specify additional
library search paths for the compiler.
* Example programs:
* Introduces a new tutorial example to demonstrate reusing output queues on
WSE-3 with `@queue_flush`. See
[topic-16-queue-flush](/csl/sdk-examples#topic-16-queue-flush).
### Resolved Issues
* Instruction traces in the SDK GUI are now supported on WSE-3.
* Fixes possible read-after-write hazard in `tile_config.teardown.exit()`.
* Fixes bug in which a runtime call to a function could cause incorrect
evaluation of comptime calls to the same function.
* Fixes bug where a dereference expression passed to `@set_dsd_base_address`
could crash the compiler.
* Fixes bug where DSDs could not be passed as comptime function parameters.
* Fixes `SdkLayout` crash with `simprint` library.
* Fixes exception propagation in `SdkRuntime` when a simulator failure occurs.
* Fixes potential segfault in `SdkLayout` caused by stale reference to
`CodeRegion`.
### Known Issues
* The `25-pt-stencil` and `histogram-torus` benchmark examples are not
supported on WSE-3.
* The bandwidth of memory transfers saturates at around 8 IO channels.
### Deprecations
* `fabric_color` in `@get_dsd` is no longer required, and emits a deprecation
warning for all `fabin_dsd` and `fabout_dsd` on WSE-3, and for `fabin_dsd`
that specify `input_queue` on WSE-2.
* Automatic input queue initialization for `fabin_dsd` operands of DSD/DSR
builtins has been removed.
* The `comptime_struct` type has been removed. See
[Migrating from comptime\_struct and @concat\_structs](/csl/comptime-struct-migration)
for a migration guide.
* The `@concat_structs` builtin has been removed. See
[Migrating from comptime\_struct and @concat\_structs](/csl/comptime-struct-migration)
for a migration guide.
## Version 1.4.0
Released 26 May 2025
**Note**
The Cerebras Wafer-Scale Cluster appliance running Cerebras ML Software 2.4 supports SDK 1.3.
[See here for SDK 1.3 documentation](https://cerebras-sdk-docs-130.netlify.app).
The Cerebras Wafer-Scale Cluster appliance running Cerebras ML Software 2.5 supports SDK 1.4,
the current version of SDK software.
### New Features and Enhancements
* (beta) New `SdkLayout` program layout specification API:
* Introduces a new `SdkLayout` Python API for specifying program layout. This API
allows the user to define retangular code regions, define color routing and switching,
automatically allocate colors, and automatically route between code regions.
* Introduces several example programs demonstrating the use of the `SdkLayout` API. See the
list of new example programs below.
* Introduces new documentation for this API. See [SdkLayout API Reference](/api-docs/sdklayout-api).
* This API is in **beta**. The `memcpy` API for data transfers and remote kernel
launches is not currently supported. CSL libraries with their own internal color routing
are not currently supported.
* CSL language and compiler enhancements:
* `@map` now supports explicit DSR arguments. DSR input arguments must be `dsr_src1` and
DSR output arguments must be `dsr_dest`. All DSR arguments should be loaded with the
`single_step` property set. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
param inDSR: dsr_src1;
param outDSR: dsr_dest;
task foo() void {
// Compute the square-root of each element of `memDSD` and
// send it out to `faboutDSD`.
@load_to_dsr(inDSR, memDSD, .{.single_step = true});
@load_to_dsr(outDSR, faboutDSD, .{.single_step = true});
@map(math_lib.sqrt_f16, inDSR, outDSR);
}
```
* Introduces support for `cb16` (`cbfloat16`) and `bfloat16` (bfloat) 16-bit floating
point types, and the associated `@fp16()` builtin. See [@fp16](/csl/language/builtins#@fp16) and
[Type System in CSL](/csl/language/types). `cbfloat16` is a Cerebras-specific 16-bit floating point format with
a 6-bit exponent and 9-bit explicit mantissa.
* On WSE-3, introduces support for microthread priority via the `.priority` field in
`@get_dsd` for `fabin_dsd` and `fabout_dsd`, and in `@allocate_fifo`. See
[Data Structure Descriptors](/csl/language/dsds).
* CSL library enhancements:
* Introduces 3D FFT kernel library. See [``](/csl/language/libraries#\).
* Introduces `tile_config.input_queue_status` and `tile_config.output_queue_status`
to query input and output queue full/ empty status registers. See
[input\_queue\_status](/csl/language/libraries#input_queue_status) and
[output\_queue\_status](/csl/language/libraries#output_queue_status).
* `SdkRuntime` host runtime enhancements:
* Introduces the `SdkRuntime` direct link API functions `send` and `receive`, which are
used to stream data into or out of the wafer via program input and output ports. This API
can be used with `SdkLayout` as demonstrated in [SdkLayout 4: Host-to-device and device-to-host data streaming](/csl/sdk-examples#sdklayout-04-h2d-d2h).
See [SdkRuntime API Reference](/api-docs/sdkruntime-api).
* Example programs:
* Introduces a series of example programs demonstrating the new `SdkLayout` API:
* [SdkLayout 1: Introduction](/csl/sdk-examples#sdklayout-01-introduction) introduces the `SdkLayout` API with a
single-PE program.
* [SdkLayout 2: Basic routing](/csl/sdk-examples#sdklayout-02-routing) demonstrates color routing with the `SdkLayout`
API and automatic color allocation.
* [SdkLayout 3: Ports and connections](/csl/sdk-examples#sdklayout-03-ports-and-connections) demonstrates automatic routing between
code regions.
* [SdkLayout 4: Host-to-device and device-to-host data streaming](/csl/sdk-examples#sdklayout-04-h2d-d2h) demonstrates the use of the `SdkRuntime`
direct link API with `SdkLayout` to create host-to-device and device-to-host streams.
* [SdkLayout 5: Generalized matrix-vector multiplication (GEMV)](/csl/sdk-examples#sdklayout-05-gemv) implements a full GEMV program with the `SdkLayout`
API.
* Introduces an example using the 3D FFT kernel library. See [3D FFT](/csl/sdk-examples#fft-3d).
### Resolved Issues
* Fixes incorrect parsing of CSL if statements whose body is an assignment without braces
(e.g. `if (cond) lhs = rhs;`)
* On WSE-2, fixes bug in which `@set_color_config` did not support all 6 available filters.
Previously, only the first four were available.
* Fixes potential stall caused by sending many small data transfers via `SdkRuntime`.
* Appliance mode compilation via `SdkCompiler` no longer allocates a system while compiling.
* Appliance mode SDK jobs launched via `SdkCompiler`, `SdkLauncher`, or `SdkRuntime` now
exit gracefully.
### Known Issues
* The `25-pt-stencil`, `histogram-torus`, and `spmv-hypersparse`
benchmark examples are not supported on WSE-3.
* Instruction traces in the SDK GUI are not supported on WSE-3.
* The bandwidth of memory transfers saturates at around 8 IO channels.
### Deprecations
* In CSL, calling a task is now an error. Only functions may be called. Tasks must
be activated.
* In CSL, dereference or access of pointers into config space is now illegal.
The `@get_config` and `@set_config` builtins should be used instead.
* WSE-1 is no longer supported.
## Version 1.3.0
Released 13 December 2024
### New Features and Enhancements
* CSL language and compiler enhancements:
* For DSD definitions, a tensor access expression is now shorthand for a `comptime_struct`
with `extent`, `stride`, and `base_address` fields. DSDs can now also be specified
using these fields directly, for example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
// These two definitions are equivalent:
var my_dsd = @get_dsd(mem1d_dsd, .{ .extent = 10, .stride = 2, .base_address = &my_arr });
var my_dsd = @get_dsd(mem1d_dsd, .{ .tensor_access = |i|{10} -> my_arr[2*i] });
```
`stride` is an optional parameter with default value 1.
See [tensor\_access](/csl/language/dsds#tensor_access) for more information.
* Memory DSD properties can now take runtime values when using the individual field
specification format. However, `mem4d_dsd` extent and stride must still be comptime known.
* Introduces inline functions, which are expanded during semantic analysis.
See [Syntax of CSL](/csl/language/syntax) for more information.
* Introduces labeled `break` and the ability to break values from blocks.
See [Syntax of CSL](/csl/language/syntax) for more information.
* Improves performance of CSL’s parser, potentially improving program compile times.
* Improves DSR allocation diagnostics when using DSDs. Upon failure to allocate, diagnostics now
contain information about operations that prevent a DSR from being allocated.
* CSL library enhancements:
* Introduces a `` library which provides wrappers around DSD op builtins that select
an appropriate builtin depending on the underlying data types, enabling more concise and
flexible code when supporting multiple data types.
See [``](/csl/language/libraries#\) for more information.
* `SdkRuntime` host runtime enhancements:
* Introduces a strided version of `memcpy_h2d` for strided host-to-device data transfers.
See `memcpy_h2d_stride` in [SdkRuntime API Reference](/api-docs/sdkruntime-api).
* Introduces row and column broadcast variants of `memcpy_h2d` for host-to-device row and
column broadcasts. See `memcpy_h2d_colbcast` and `memcpy_h2d_rowbcast` in
[SdkRuntime API Reference](/api-docs/sdkruntime-api).
Also see the example program [Host-to-Device Broadcast Test](/csl/sdk-examples#row-col-broadcast).
* Example programs:
* Introduces a new example program [Host-to-Device Broadcast Test](/csl/sdk-examples#row-col-broadcast) to demonstrate row and
column broadcasts for host-to-device data transfers.
### Resolved Issues
* Fixes an issue in the `` library where messages were limited to only 16
wavelets. The maximum message size is 32 wavelets.
* Fixes bugs in the `` library in which `encode_payload()` could index out of bounds,
and not set `NOCE` bit on unused commands.
* Fixes a bug in which sequential `@map` operations within a function would not be able to reuse
DSRs.
### Known Issues
* The `25-pt-stencil`, `histogram-torus`, and `spmv-hypersparse`
benchmark examples are not yet supported on WSE-3.
* Instruction traces in the SDK GUI are not yet supported on WSE-3.
* The bandwidth of memory transfers saturates at around 8 IO channels.
## Version 1.2.0
Released 28 June 2024
**Note**
The Cerebras Wafer-Scale Cluster appliance running Cerebras ML Software 2.2 supports SDK 1.1.
[See here for SDK 1.1 documentation](https://cerebras-sdk-docs-110.netlify.app).
The Cerebras Wafer-Scale Cluster appliance running Cerebras ML Software 2.3 supports SDK 1.2,
the current version of SDK software.
### New Features and Enhancements
* CSL language and compiler enhancements:
* Introduces `inline` `for`-loops, which are unrolled at compile time.
The body of an `inline` `for`-loop may assign to a `comptime`
variable. For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
fn length(comptime array: anytype) comptime_int {
comptime var result = 0;
// This loop will be inlined.
inline for (array) |v| {
result += 1;
}
return result;
}
```
* Introduces the `@queue_flush` and `@set_empty_queue_handler` builtin
for WSE-3. See [@queue\_flush](/csl/language/builtins_wse3#@queue_flush).
* Runtime `on_control` values in DSD operations are now supported.
For example:
```csl theme={"languages":{"custom":["/languages/csl-tmlanguage.json"]}}
fn f(out: fabout_dsd, in: fabin_dsd, act_id: local_task_id) void {
@fmovh(out, in, .{
.async = true, .on_control = .{ .activate = act_id }});
}
```
* Improves `void` type semantics, enabling optionally specified module
parameters and function arguments.
* Significantly improves compile times for large programs. Compilation time
for full-wafer programs may be improved as much as 10x.
* CSL library enhancements:
* Introduces a `` library for runtime debug printing to the
simulator log. See [``](/csl/language/libraries#\).
* Introduces a `` library for creating control wavelet payloads.
See [``](/csl/language/libraries#\).
* Introduces a `` library for WSE-3 point-to-point
communication. See [``](/csl/language/libraries_wse3#\).
* Introduces the `queue_flush` module within the `` library
for WSE-3, which can be used for querying when a queue is flushed and to
exit the flushed state.
See [queue\_flush](/csl/language/libraries_wse3#queue_flush).
* Adds WSE-3 support to the `collectives_2d` library.
* `SdkRuntime` host runtime enhancements:
* Adds WSE-3 support for `memcpy` streaming mode.
* Example programs:
* Reorganizes and updates all tutorial example programs with WSE-3 support.
* Introduces two new tutorial examples for switches, demonstrating use of
the `` library. See [Topic 6: Switches](/csl/sdk-examples#topic-06-switches) and
[Topic 7: Switches and Control Entrypoints](/csl/sdk-examples#topic-07-switches-entrypt).
* Introduces a new tutorial example to demonstrate the ``
library. See [Topic 13: Simprint Library](/csl/sdk-examples#topic-13-simprint).
* Introduces a new tutorial example to demonstrate color swapping on WSE-2.
See [Topic 14: Color Swap](/csl/sdk-examples#topic-14-color-swap).
* Adds WSE-3 support to the `wide-multiplication`, `residual`,
`mandelbrot`, `gemv-collectives_2d`, `gemv-checkerboard-pattern`,
`gemm-collectives_2d`, `7pt-stencil-spmv`, `bicgstab`,
`conjugateGradient`, `preconditionedConjugateGradient`, and
`powerMethod` benchmark example programs.
### Resolved Issues
* Adds `memcpy` streaming support for WSE-3.
* Adds WSE-3 support for the `` library.
* Fixes potential bug in the `` library related to
reconfiguring the library’s colors.
* Fixes potential bug in the `` library related to reconfiguring
the library’s colors.
### Known Issues
* The `25-pt-stencil`, `histogram-torus`, and `spmv-hypersparse`
benchmark examples are not yet supported on WSE-3.
* The SDK GUI is not yet supported on WSE-3.
* The bandwidth of memory transfers saturates at around 8 IO channels.
### Deprecations
* The deprecated `@get_color_id` builtin to get the numerical value of a
color is now removed. Use `@get_int` instead.
* Use of `@get_color` on any ID other than a routable color ID is no longer
supported.
* `tile_config.reg_ptr` has been removed. Use `@get_config` and
`@set_config` for direct manipulation of config space addresses.
## Version 1.1.0
Released 10 April 2024
This version of the Cerebras SDK is the first with experimental support
for the WSE-3, the third generation Cerebras architecture.
The WSE-3 is the wafer-scale processor powering the CS-3 Cerebras system.
**Note**
The Cerebras Wafer-Scale Cluster appliance running Cerebras ML Software 2.0 supports SDK 0.9.
[See here for SDK 0.9 documentation](https://cerebras-sdk-docs-090.netlify.app).
The Cerebras Wafer-Scale Cluster appliance running Cerebras ML Software 2.1 supports SDK 1.0.
[See here for SDK 1.0 documentation](https://cerebras-sdk-docs-100.netlify.app).
The Cerebras Wafer-Scale Cluster appliance running Cerebras ML Software 2.2 supports SDK 1.1,
the current version of SDK software.
### New Features and Enhancements
* CSL language and compiler enhancements:
* Introduces initial support for WSE-3.
* Introduces `ut_id` type and `@get_ut_id` builtin for representing
microthread IDs. This feature is WSE-3 only.
* Introduces runtime `@get_config` and `@set_config` support.
* Introduces `i64` and `u64` types, and support in `