llama: refactor llama_decode_impl (#11381)

This fixes segmentation fault error when running tests when no metal
devices are available (for example, when not linked with Core Graphics
framework or otherwise).

.devops/vulkan.Dockerfile

@@ -1,4 +1,4 @@
-ARG UBUNTU_VERSION=jammy
+ARG UBUNTU_VERSION=22.04
 
 FROM ubuntu:$UBUNTU_VERSION AS build
 
@@ -34,7 +34,7 @@ RUN mkdir -p /app/full \
 FROM ubuntu:$UBUNTU_VERSION AS base
 
 RUN apt-get update \
-    && apt-get install -y libgomp1 curl\
+    && apt-get install -y libgomp1 curl libvulkan-dev \
     && apt autoremove -y \
     && apt clean -y \
     && rm -rf /tmp/* /var/tmp/* \

.github/workflows/docker.yml

@@ -32,10 +32,12 @@ jobs:
     env:
       COMMIT_SHA: ${{ github.sha }}
     strategy:
+      fail-fast: false
       matrix:
         config:
           # Multi-stage build
-          - { tag: "cpu", dockerfile: ".devops/cpu.Dockerfile", platforms: "linux/amd64,linux/arm64", full: true, light: true, server: true, freediskspace: false}
+          - { tag: "cpu", dockerfile: ".devops/cpu.Dockerfile", platforms: "linux/amd64", full: true, light: true, server: true, freediskspace: false}
+          - { tag: "cpu", dockerfile: ".devops/cpu.Dockerfile", platforms: "linux/arm64", full: true, light: true, server: true, freediskspace: false}
           - { tag: "cuda", dockerfile: ".devops/cuda.Dockerfile", platforms: "linux/amd64", full: true, light: true, server: true, freediskspace: false}
           - { tag: "musa", dockerfile: ".devops/musa.Dockerfile", platforms: "linux/amd64", full: true, light: true, server: true, freediskspace: false}
           - { tag: "intel", dockerfile: ".devops/intel.Dockerfile", platforms: "linux/amd64", full: true, light: true, server: true, freediskspace: false}

ggml/src/ggml-metal/ggml-metal.m

@@ -19,7 +19,10 @@
 // max number of MTLCommandBuffer used to submit a graph for processing
 #define GGML_METAL_MAX_COMMAND_BUFFERS 8
 
-#define UNUSED(x) (void)(x)
+// create residency sets only on macOS >= 15.0
+#if TARGET_OS_OSX && __MAC_OS_X_VERSION_MAX_ALLOWED >= 150000
+#define GGML_METAL_HAS_RESIDENCY_SETS 1
+#endif
 
 // globals
 
@@ -39,6 +42,7 @@ static struct ggml_backend_metal_device_context {
 
     bool has_simdgroup_reduction;
     bool has_simdgroup_mm;
+    bool has_residency_sets;
     bool has_bfloat;
     bool use_bfloat;
 
@@ -48,6 +52,7 @@ static struct ggml_backend_metal_device_context {
     /*.mtl_device_ref_count    =*/ 0,
     /*.has_simdgroup_reduction =*/ false,
     /*.has_simdgroup_mm        =*/ false,
+    /*.has_residency_sets      =*/ false,
     /*.has_bfloat              =*/ false,
     /*.use_bfloat              =*/ false,
     /*.name                    =*/ "",
@@ -59,12 +64,18 @@ static id<MTLDevice> ggml_backend_metal_device_acq(struct ggml_backend_metal_dev
 
     if (ctx->mtl_device == nil) {
         ctx->mtl_device = MTLCreateSystemDefaultDevice();
+    }
 
+    if (ctx->mtl_device) {
         ctx->has_simdgroup_reduction  = [ctx->mtl_device supportsFamily:MTLGPUFamilyApple7];
         ctx->has_simdgroup_reduction |= [ctx->mtl_device supportsFamily:MTLGPUFamilyMetal3_GGML];
 
         ctx->has_simdgroup_mm = [ctx->mtl_device supportsFamily:MTLGPUFamilyApple7];
 
+#if defined(GGML_METAL_HAS_RESIDENCY_SETS)
+        ctx->has_residency_sets = getenv("GGML_METAL_NO_RESIDENCY") == NULL;
+#endif
+
         ctx->has_bfloat  = [ctx->mtl_device supportsFamily:MTLGPUFamilyMetal3_GGML];
         ctx->has_bfloat |= [ctx->mtl_device supportsFamily:MTLGPUFamilyApple6];
 
@@ -90,8 +101,10 @@ static void ggml_backend_metal_device_rel(struct ggml_backend_metal_device_conte
     ctx->mtl_device_ref_count--;
 
     if (ctx->mtl_device_ref_count == 0) {
-        [ctx->mtl_device release];
-        ctx->mtl_device = nil;
+        if (ctx->mtl_device) {
+            [ctx->mtl_device release];
+            ctx->mtl_device = nil;
+        }
     }
 }
 
@@ -483,6 +496,11 @@ static struct ggml_backend_metal_context * ggml_metal_init(ggml_backend_dev_t de
     GGML_LOG_INFO("%s: picking default device: %s\n", __func__, [[device name] UTF8String]);
 
     ctx->queue  = [device newCommandQueue];
+    if (ctx->queue == nil) {
+        GGML_LOG_ERROR("%s: error: failed to create command queue\n", __func__);
+        return NULL;
+    }
+
     ctx->d_queue = dispatch_queue_create("ggml-metal", DISPATCH_QUEUE_CONCURRENT);
 
     id<MTLLibrary> metal_library;
@@ -649,6 +667,7 @@ static struct ggml_backend_metal_context * ggml_metal_init(ggml_backend_dev_t de
 
     GGML_LOG_INFO("%s: simdgroup reduction   = %s\n", __func__, ctx_dev->has_simdgroup_reduction     ? "true" : "false");
     GGML_LOG_INFO("%s: simdgroup matrix mul. = %s\n", __func__, ctx_dev->has_simdgroup_mm            ? "true" : "false");
+    GGML_LOG_INFO("%s: has residency sets    = %s\n", __func__, ctx_dev->has_residency_sets          ? "true" : "false");
     GGML_LOG_INFO("%s: has bfloat            = %s\n", __func__, ctx_dev->has_bfloat                  ? "true" : "false");
     GGML_LOG_INFO("%s: use bfloat            = %s\n", __func__, ctx_dev->use_bfloat                  ? "true" : "false");
     GGML_LOG_INFO("%s: hasUnifiedMemory      = %s\n", __func__, ctx_dev->mtl_device.hasUnifiedMemory ? "true" : "false");
@@ -1035,8 +1054,70 @@ struct ggml_backend_metal_buffer_context {
     // multiple buffers are used only to avoid the maximum buffer size limitation when using mmap
     int n_buffers;
     struct ggml_backend_metal_buffer buffers[GGML_METAL_MAX_BUFFERS];
+
+    // optional MTLResidencySet
+    id rset;
 };
 
+// rset init
+static bool ggml_backend_metal_buffer_rset_init(
+        struct ggml_backend_metal_buffer_context * ctx,
+        struct ggml_backend_metal_device_context * ctx_dev,
+        id<MTLDevice> device) {
+    ctx->rset = nil;
+
+    if (!ctx_dev->has_residency_sets) {
+        return true;
+    }
+
+#if defined(GGML_METAL_HAS_RESIDENCY_SETS)
+    if (@available(macOS 15.0, *)) {
+        MTLResidencySetDescriptor * desc = [[MTLResidencySetDescriptor alloc] init];
+        desc.label = @"ggml_backend_metal";
+        desc.initialCapacity = ctx->n_buffers;
+
+        NSError * error;
+        ctx->rset = [device newResidencySetWithDescriptor:desc error:&error];
+        if (error) {
+            GGML_LOG_ERROR("%s: error: %s\n", __func__, [[error description] UTF8String]);
+            [desc release];
+            return false;
+        }
+
+        [desc release];
+
+        for (int i = 0; i < ctx->n_buffers; i++) {
+            [ctx->rset addAllocation:ctx->buffers[i].metal];
+        }
+
+        [ctx->rset commit];
+        [ctx->rset requestResidency];
+
+        return true;
+    }
+#else
+    GGML_UNUSED(ctx_dev);
+    GGML_UNUSED(device);
+#endif
+
+    return true;
+}
+
+// rset free
+static void ggml_backend_metal_buffer_rset_free(struct ggml_backend_metal_buffer_context * ctx) {
+#if defined(GGML_METAL_HAS_RESIDENCY_SETS)
+    if (@available(macOS 15.0, *)) {
+        if (ctx->rset) {
+            [ctx->rset endResidency];
+            [ctx->rset removeAllAllocations];
+            [ctx->rset release];
+        }
+    }
+#else
+    GGML_UNUSED(ctx);
+#endif
+}
+
 // finds the Metal buffer that contains the tensor data on the GPU device
 // the assumption is that there is 1-to-1 mapping between the host and device memory buffers, so we can find the
 // Metal buffer based on the host memory pointer
@@ -4176,6 +4257,8 @@ static void ggml_backend_metal_buffer_free_buffer(ggml_backend_buffer_t buffer)
     for (int i = 0; i < ctx->n_buffers; i++) {
         [ctx->buffers[i].metal release];
     }
+
+    ggml_backend_metal_buffer_rset_free(ctx);
     ggml_backend_metal_device_rel(buffer->buft->device->context);
 
     if (ctx->owned) {
@@ -4198,19 +4281,19 @@ static void * ggml_backend_metal_buffer_get_base(ggml_backend_buffer_t buffer) {
 static void ggml_backend_metal_buffer_memset_tensor(ggml_backend_buffer_t buffer, struct ggml_tensor * tensor, uint8_t value, size_t offset, size_t size) {
     memset((char *)tensor->data + offset, value, size);
 
-    UNUSED(buffer);
+    GGML_UNUSED(buffer);
 }
 
 static void ggml_backend_metal_buffer_set_tensor(ggml_backend_buffer_t buffer, struct ggml_tensor * tensor, const void * data, size_t offset, size_t size) {
     memcpy((char *)tensor->data + offset, data, size);
 
-    UNUSED(buffer);
+    GGML_UNUSED(buffer);
 }
 
 static void ggml_backend_metal_buffer_get_tensor(ggml_backend_buffer_t buffer, const struct ggml_tensor * tensor, void * data, size_t offset, size_t size) {
     memcpy(data, (const char *)tensor->data + offset, size);
 
-    UNUSED(buffer);
+    GGML_UNUSED(buffer);
 }
 
 static bool ggml_backend_metal_buffer_cpy_tensor(ggml_backend_buffer_t buffer, const struct ggml_tensor * src, struct ggml_tensor * dst) {
@@ -4220,7 +4303,7 @@ static bool ggml_backend_metal_buffer_cpy_tensor(ggml_backend_buffer_t buffer, c
     }
     return false;
 
-    UNUSED(buffer);
+    GGML_UNUSED(buffer);
 }
 
 static void ggml_backend_metal_buffer_clear(ggml_backend_buffer_t buffer, uint8_t value) {
@@ -4246,7 +4329,7 @@ static struct ggml_backend_buffer_i ggml_backend_metal_buffer_i = {
 static const char * ggml_backend_metal_buffer_type_get_name(ggml_backend_buffer_type_t buft) {
     return "Metal";
 
-    UNUSED(buft);
+    GGML_UNUSED(buft);
 }
 
 static void ggml_backend_metal_log_allocated_size(id<MTLDevice> device, size_t size_aligned) {
@@ -4270,8 +4353,8 @@ static void ggml_backend_metal_log_allocated_size(id<MTLDevice> device, size_t s
     }
 #endif
 #endif
-    UNUSED(device);
-    UNUSED(size_aligned);
+    GGML_UNUSED(device);
+    GGML_UNUSED(size_aligned);
 }
 
 static ggml_backend_buffer_t ggml_backend_metal_buffer_type_alloc_buffer(ggml_backend_buffer_type_t buft, size_t size) {
@@ -4284,7 +4367,8 @@ static ggml_backend_buffer_t ggml_backend_metal_buffer_type_alloc_buffer(ggml_ba
         size_aligned += (size_page - (size_aligned % size_page));
     }
 
-    id<MTLDevice> device = ggml_backend_metal_device_acq(buft->device->context);
+    struct ggml_backend_metal_device_context * ctx_dev = (struct ggml_backend_metal_device_context *)buft->device->context;
+    id<MTLDevice> device = ggml_backend_metal_device_acq(ctx_dev);
 
     ctx->all_data = ggml_metal_host_malloc(size_aligned);
     ctx->all_size = size_aligned;
@@ -4307,7 +4391,14 @@ static ggml_backend_buffer_t ggml_backend_metal_buffer_type_alloc_buffer(ggml_ba
     if (size_aligned > 0 && (ctx->all_data == NULL || ctx->buffers[0].metal == nil)) {
         GGML_LOG_ERROR("%s: error: failed to allocate buffer, size = %8.2f MiB\n", __func__, size_aligned / 1024.0 / 1024.0);
         free(ctx);
-        ggml_backend_metal_device_rel(buft->device->context);
+        ggml_backend_metal_device_rel(ctx_dev);
+        return NULL;
+    }
+
+    if (!ggml_backend_metal_buffer_rset_init(ctx, ctx_dev, device)) {
+        GGML_LOG_ERROR("%s: error: failed to initialize residency set\n", __func__);
+        free(ctx);
+        ggml_backend_metal_device_rel(ctx_dev);
         return NULL;
     }
 
@@ -4318,7 +4409,7 @@ static ggml_backend_buffer_t ggml_backend_metal_buffer_type_alloc_buffer(ggml_ba
 
 static size_t ggml_backend_metal_buffer_type_get_alignment(ggml_backend_buffer_type_t buft) {
     return 32;
-    UNUSED(buft);
+    GGML_UNUSED(buft);
 }
 
 static size_t ggml_backend_metal_buffer_type_get_max_size(ggml_backend_buffer_type_t buft) {
@@ -4328,13 +4419,13 @@ static size_t ggml_backend_metal_buffer_type_get_max_size(ggml_backend_buffer_ty
 
     return max_size;
 
-    UNUSED(buft);
+    GGML_UNUSED(buft);
 }
 
 static bool ggml_backend_metal_buffer_type_is_host(ggml_backend_buffer_type_t buft) {
     return true;
 
-    UNUSED(buft);
+    GGML_UNUSED(buft);
 }
 
 ggml_backend_buffer_type_t ggml_backend_metal_buffer_type(void) {
@@ -4357,7 +4448,7 @@ ggml_backend_buffer_type_t ggml_backend_metal_buffer_type(void) {
 static const char * ggml_backend_metal_buffer_from_ptr_type_get_name(ggml_backend_buffer_type_t buft) {
     return "Metal_Mapped";
 
-    UNUSED(buft);
+    GGML_UNUSED(buft);
 }
 
 static ggml_backend_buffer_type_t ggml_backend_metal_buffer_from_ptr_type(void) {
@@ -4400,7 +4491,8 @@ ggml_backend_buffer_t ggml_backend_metal_buffer_from_ptr(void * data, size_t siz
         size_aligned += (size_page - (size_aligned % size_page));
     }
 
-    id<MTLDevice> device = ggml_backend_metal_device_acq(&g_ggml_ctx_dev_main);
+    struct ggml_backend_metal_device_context * ctx_dev = &g_ggml_ctx_dev_main;
+    id<MTLDevice> device = ggml_backend_metal_device_acq(ctx_dev);
 
     // the buffer fits into the max buffer size allowed by the device
     if (size_aligned <= device.maxBufferLength) {
@@ -4453,6 +4545,13 @@ ggml_backend_buffer_t ggml_backend_metal_buffer_from_ptr(void * data, size_t siz
         }
     }
 
+    if (!ggml_backend_metal_buffer_rset_init(ctx, ctx_dev, device)) {
+        GGML_LOG_ERROR("%s: error: failed to initialize residency set\n", __func__);
+        free(ctx);
+        ggml_backend_metal_device_rel(ctx_dev);
+        return NULL;
+    }
+
     return ggml_backend_buffer_init(ggml_backend_metal_buffer_from_ptr_type(), ggml_backend_metal_buffer_i, ctx, size);
 }
 
@@ -4461,7 +4560,7 @@ ggml_backend_buffer_t ggml_backend_metal_buffer_from_ptr(void * data, size_t siz
 static const char * ggml_backend_metal_name(ggml_backend_t backend) {
     return "Metal";
 
-    UNUSED(backend);
+    GGML_UNUSED(backend);
 }
 
 static void ggml_backend_metal_free(ggml_backend_t backend) {
@@ -4766,6 +4865,13 @@ static ggml_backend_buffer_t ggml_backend_metal_device_buffer_from_ptr(ggml_back
         }
     }
 
+    if (!ggml_backend_metal_buffer_rset_init(ctx, ctx_dev, device)) {
+        GGML_LOG_ERROR("%s: error: failed to initialize residency set\n", __func__);
+        free(ctx);
+        ggml_backend_metal_device_rel(ctx_dev);
+        return NULL;
+    }
+
     return ggml_backend_buffer_init(ggml_backend_metal_buffer_from_ptr_type(), ggml_backend_metal_buffer_i, ctx, size);
 }
 
@@ -4779,7 +4885,7 @@ static bool ggml_backend_metal_device_supports_buft(ggml_backend_dev_t dev, ggml
     return buft->iface.get_name == ggml_backend_metal_buffer_type_get_name ||
             buft->iface.get_name == ggml_backend_metal_buffer_from_ptr_type_get_name;
 
-    UNUSED(dev);
+    GGML_UNUSED(dev);
 }
 
 static bool ggml_backend_metal_device_offload_op(ggml_backend_dev_t dev, const struct ggml_tensor * op) {

src/llama.cpp

@@ -8432,13 +8432,141 @@ static enum ggml_status llama_graph_compute(
     return status;
 }
 
+static int llama_prepare_sbatch(
+        llama_context     & lctx,
+        const llama_batch & batch,
+        uint32_t          & n_outputs) {
+    const auto & model   = lctx.model;
+    const auto & hparams = model.hparams;
+    const auto & cparams = lctx.cparams;
+
+    const uint32_t n_tokens_all = batch.n_tokens;
+    const  int64_t n_embd       = hparams.n_embd;
+
+    // this indicates we are doing pooled embedding, so we ignore batch.logits and output all tokens
+    const bool embd_pooled = cparams.embeddings && cparams.pooling_type != LLAMA_POOLING_TYPE_NONE;
+
+    GGML_ASSERT((!batch.token && batch.embd) || (batch.token && !batch.embd)); // NOLINT
+    if (batch.token) {
+        for (uint32_t i = 0; i < n_tokens_all; ++i) {
+            if (batch.token[i] < 0 || uint32_t(batch.token[i]) >= model.vocab.n_tokens()) {
+                LLAMA_LOG_ERROR("%s: invalid token[%d] = %d\n", __func__, i, batch.token[i]);
+                return -1;
+            }
+        }
+    }
+    GGML_ASSERT(n_tokens_all <= cparams.n_batch);
+    GGML_ASSERT((cparams.causal_attn || cparams.n_ubatch >= n_tokens_all) && "non-causal attention requires n_ubatch >= n_tokens");
+
+    lctx.n_queued_tokens += n_tokens_all;
+    lctx.embd_seq.clear();
+
+    // count outputs
+    if (batch.logits && !embd_pooled) {
+        for (uint32_t i = 0; i < n_tokens_all; ++i) {
+            n_outputs += batch.logits[i] != 0;
+        }
+    } else if (lctx.logits_all || embd_pooled) {
+        n_outputs = n_tokens_all;
+    } else {
+        // keep last output only
+        n_outputs = 1;
+    }
+
+    lctx.sbatch.from_batch(batch, n_embd,
+        /* simple_split */ !lctx.kv_self.recurrent,
+        /* logits_all   */ n_outputs == n_tokens_all);
+
+    // reserve output buffer
+    if (llama_output_reserve(lctx, n_outputs) < n_outputs) {
+        LLAMA_LOG_ERROR("%s: could not reserve space for batch with %u outputs\n", __func__, n_outputs);
+        return -2;
+    };
+
+    return 0;
+}
+
+static int llama_prepare_ubatch(
+        llama_context          & lctx,
+        llama_kv_slot_restorer & kv_slot_restorer,
+        llama_ubatch           & ubatch,
+        const uint32_t           n_outputs,
+        const uint32_t           n_tokens_all) {
+    GGML_ASSERT(lctx.sbatch.n_tokens > 0);
+
+    auto       & kv_self = lctx.kv_self;
+    const auto & cparams = lctx.cparams;
+    const auto & hparams = lctx.model.hparams;
+
+    // this indicates we are doing pooled embedding, so we ignore batch.logits and output all tokens
+    const bool embd_pooled = cparams.embeddings && cparams.pooling_type != LLAMA_POOLING_TYPE_NONE;
+
+    if (lctx.kv_self.recurrent) {
+        if (embd_pooled) {
+            // Pooled embeddings cannot be split across ubatches (yet)
+            ubatch = lctx.sbatch.split_seq(cparams.n_ubatch);
+        } else {
+            // recurrent model architectures are easier to implement
+            // with equal-length sequences
+            ubatch = lctx.sbatch.split_equal(cparams.n_ubatch);
+        }
+    } else {
+        ubatch = lctx.sbatch.split_simple(cparams.n_ubatch);
+    }
+
+    // count the outputs in this u_batch
+    {
+        int32_t n_outputs_new = 0;
+
+        if (n_outputs == n_tokens_all) {
+            n_outputs_new = ubatch.n_tokens;
+        } else {
+            GGML_ASSERT(ubatch.output);
+            for (uint32_t i = 0; i < ubatch.n_tokens; i++) {
+                n_outputs_new += int32_t(ubatch.output[i] != 0);
+            }
+        }
+
+        // needs to happen before the graph is built
+        lctx.n_outputs = n_outputs_new;
+    }
+
+    // non-causal masks do not use the KV cache
+    if (hparams.causal_attn) {
+        llama_kv_cache_update(&lctx);
+
+        // if we have enough unused cells before the current head ->
+        //   better to start searching from the beginning of the cache, hoping to fill it
+        if (kv_self.head > kv_self.used + 2*ubatch.n_tokens) {
+            kv_self.head = 0;
+        }
+
+        const auto slot = llama_kv_cache_find_slot(kv_self, ubatch);
+        if (!slot) {
+            return 1;
+        }
+        kv_slot_restorer.save(slot);
+
+        if (!kv_self.recurrent) {
+            // a heuristic, to avoid attending the full cache if it is not yet utilized
+            // after enough generations, the benefit from this heuristic disappears
+            // if we start defragmenting the cache, the benefit from this will be more important
+            const uint32_t pad = llama_kv_cache_get_padding(cparams);
+            kv_self.n = std::min(kv_self.size, std::max(pad, GGML_PAD(llama_kv_cache_cell_max(kv_self), pad)));
+            //kv_self.n = llama_kv_cache_cell_max(kv_self);
+        }
+    }
+
+    return 0;
+}
+
 // decode a batch of tokens by evaluating the transformer
 // in case of unsuccessful decoding (error or warning),
 // the kv_cache state will be returned to its original state
 // (for non-recurrent models) or cleaned (for recurrent models)
 //
 //   - lctx:      llama context
-//   - batch:     batch to evaluate
+//   - inp_batch: batch to evaluate
 //
 // return 0 on success
 // return positive int on warning
@@ -8455,37 +8583,18 @@ static int llama_decode_impl(
         return -1;
     }
 
-    // temporary allocate memory for the input batch if needed
+    // temporarily allocate memory for the input batch if needed
     llama_batch_allocr batch_allocr(inp_batch, inp_batch.pos ? -1 : lctx.kv_self.max_pos() + 1);
-
     const llama_batch & batch = batch_allocr.batch;
-    const uint32_t n_tokens_all = batch.n_tokens;
 
     const auto & model   = lctx.model;
     const auto & vocab   = model.vocab;
     const auto & hparams = model.hparams;
     const auto & cparams = lctx.cparams;
 
-    GGML_ASSERT((!batch.token && batch.embd) || (batch.token && !batch.embd)); // NOLINT
-
-    if (batch.token) {
-        for (uint32_t i = 0; i < n_tokens_all; ++i) {
-            if (batch.token[i] < 0 || (uint32_t) batch.token[i] >= model.vocab.n_tokens()) {
-                LLAMA_LOG_ERROR("%s: invalid token[%d] = %d\n", __func__, i, batch.token[i]);
-                return -1;
-            }
-        }
-    }
-
-    GGML_ASSERT(n_tokens_all <= cparams.n_batch);
-
-    GGML_ASSERT((cparams.causal_attn || cparams.n_ubatch >= n_tokens_all) && "non-causal attention requires n_ubatch >= n_tokens");
-
     if (lctx.t_compute_start_us == 0) {
         lctx.t_compute_start_us = ggml_time_us();
     }
-    lctx.n_queued_tokens += n_tokens_all;
-
     auto & kv_self = lctx.kv_self;
     llama_kv_slot_restorer kv_slot_restorer(kv_self);
 
@@ -8495,99 +8604,27 @@ static int llama_decode_impl(
     uint32_t n_outputs = 0;
     uint32_t n_outputs_prev = 0;
 
-    const auto n_ubatch = cparams.n_ubatch;
-
-    // this indicates we are doing pooled embedding, so we ignore batch.logits and output all tokens
-    const bool embd_pooled = cparams.embeddings && cparams.pooling_type != LLAMA_POOLING_TYPE_NONE;
-
-    lctx.embd_seq.clear();
-
-    // count outputs
-    if (batch.logits && !embd_pooled) {
-        for (uint32_t i = 0; i < n_tokens_all; ++i) {
-            n_outputs += batch.logits[i] != 0;
+    {
+        const int ret = llama_prepare_sbatch(lctx, batch, n_outputs);
+        if (ret != 0) {
+            return ret;
         }
-    } else if (lctx.logits_all || embd_pooled) {
-        n_outputs = n_tokens_all;
-    } else {
-        // keep last output only
-        n_outputs = 1;
     }
 
-    lctx.sbatch.from_batch(batch, n_embd,
-        /* simple_split */ !kv_self.recurrent,
-        /* logits_all   */ n_outputs == n_tokens_all);
-
-    // reserve output buffer
-    if (llama_output_reserve(lctx, n_outputs) < n_outputs) {
-        LLAMA_LOG_ERROR("%s: could not reserve space for batch with %u outputs\n", __func__, n_outputs);
-        return -2;
-    };
-
     while (lctx.sbatch.n_tokens > 0) {
         llama_ubatch ubatch;
-        if (kv_self.recurrent) {
-            if (embd_pooled) {
-                // Pooled embeddings cannot be split across ubatches (yet)
-                ubatch = lctx.sbatch.split_seq(n_ubatch);
-            } else {
-                // recurrent model architectures are easier to implement
-                // with equal-length sequences
-                ubatch = lctx.sbatch.split_equal(n_ubatch);
-            }
-        } else {
-            ubatch = lctx.sbatch.split_simple(n_ubatch);
-        }
-        const uint32_t n_tokens = ubatch.n_tokens;
-
-        // count the outputs in this u_batch
         {
-            int32_t n_outputs_new = 0;
-
-            if (n_outputs == n_tokens_all) {
-                n_outputs_new = n_tokens;
-            } else {
-                GGML_ASSERT(ubatch.output);
-                for (uint32_t i = 0; i < n_tokens; i++) {
-                    n_outputs_new += (int32_t) (ubatch.output[i] != 0);
-                }
+            const int ret = llama_prepare_ubatch(lctx, kv_slot_restorer, ubatch, n_outputs, batch.n_tokens);
+            if (ret != 0) {
+                return ret;
             }
-
-            // needs to happen before the graph is built
-            lctx.n_outputs = n_outputs_new;
         }
 
-        int n_threads = n_tokens == 1 ? cparams.n_threads : cparams.n_threads_batch;
-        ggml_threadpool_t threadpool = n_tokens == 1 ? lctx.threadpool : lctx.threadpool_batch;
+        const int         n_threads  = ubatch.n_tokens == 1 ? cparams.n_threads : cparams.n_threads_batch;
+        ggml_threadpool_t threadpool = ubatch.n_tokens == 1 ? lctx.threadpool   : lctx.threadpool_batch;
 
         GGML_ASSERT(n_threads > 0);
 
-        // non-causal masks do not use the KV cache
-        if (hparams.causal_attn) {
-            llama_kv_cache_update(&lctx);
-
-            // if we have enough unused cells before the current head ->
-            //   better to start searching from the beginning of the cache, hoping to fill it
-            if (kv_self.head > kv_self.used + 2*n_tokens) {
-                kv_self.head = 0;
-            }
-
-            const auto slot = llama_kv_cache_find_slot(kv_self, ubatch);
-            if (!slot) {
-                return 1;
-            }
-            kv_slot_restorer.save(slot);
-
-            if (!kv_self.recurrent) {
-                // a heuristic, to avoid attending the full cache if it is not yet utilized
-                // after enough generations, the benefit from this heuristic disappears
-                // if we start defragmenting the cache, the benefit from this will be more important
-                const uint32_t pad = llama_kv_cache_get_padding(cparams);
-                kv_self.n = std::min(kv_self.size, std::max(pad, GGML_PAD(llama_kv_cache_cell_max(kv_self), pad)));
-                //kv_self.n = llama_kv_cache_cell_max(kv_self);
-            }
-        }
-
         //printf("kv_self.n = %5d, kv_self.used = %5d, kv_self.head = %5d\n", kv_self.n, kv_self.used, kv_self.head);
 
         ggml_backend_sched_reset(lctx.sched.get());
@@ -8640,7 +8677,7 @@ static int llama_decode_impl(
 
         // update the kv ring buffer
         {
-            kv_self.head += n_tokens;
+            kv_self.head += ubatch.n_tokens;
 
             // Ensure kv cache head points to a valid index.
             if (kv_self.head >= kv_self.size) {