metal : warp-based reduce for rms_norm

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Georgi Gerganov 2023-11-30 22:21:30 +02:00
parent 55717c98c4
commit c4db59230d
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GPG key ID: 449E073F9DC10735
2 changed files with 28 additions and 35 deletions

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@ -447,14 +447,13 @@ kernel void kernel_rms_norm(
constant int64_t & ne00,
constant uint64_t & nb01,
constant float & eps,
threadgroup float * sum [[threadgroup(0)]],
threadgroup float * buf [[threadgroup(0)]],
uint tgpig[[threadgroup_position_in_grid]],
uint tpitg[[thread_position_in_threadgroup]],
uint sgitg[[simdgroup_index_in_threadgroup]],
uint tiisg[[thread_index_in_simdgroup]],
uint ntg[[threads_per_threadgroup]]) {
device const float4 * x = (device const float4 *) ((device const char *) src0 + tgpig*nb01);
device const float * x_scalar = (device const float *) x;
device const float4 * x = (device const float4 *) ((device const char *) src0 + tgpig*nb01);
float4 sumf = 0;
float all_sum = 0;
@ -465,40 +464,30 @@ kernel void kernel_rms_norm(
}
all_sum = sumf[0] + sumf[1] + sumf[2] + sumf[3];
all_sum = simd_sum(all_sum);
if (tiisg == 0) {
sum[sgitg] = all_sum;
}
threadgroup_barrier(mem_flags::mem_threadgroup);
// broadcast, simd group number is ntg / 32
for (uint i = ntg / 32 / 2; i > 0; i /= 2) {
if (tpitg < i) {
sum[tpitg] += sum[tpitg + i];
}
}
if (tpitg == 0) {
for (int i = 4 * (ne00 / 4); i < ne00; i++) {
sum[0] += x_scalar[i];
if (ntg > N_SIMDWIDTH) {
if (sgitg == 0) {
buf[tiisg] = 0.0f;
}
sum[0] /= ne00;
threadgroup_barrier(mem_flags::mem_threadgroup);
if (tiisg == 0) {
buf[sgitg] = all_sum;
}
threadgroup_barrier(mem_flags::mem_threadgroup);
all_sum = buf[tiisg];
all_sum = simd_sum(all_sum);
}
threadgroup_barrier(mem_flags::mem_threadgroup);
const float mean = sum[0];
const float mean = all_sum/ne00;
const float scale = 1.0f/sqrt(mean + eps);
device float4 * y = (device float4 *) (dst + tgpig*ne00);
device float * y_scalar = (device float *) y;
for (int i00 = tpitg; i00 < ne00/4; i00 += ntg) {
y[i00] = x[i00] * scale;
}
if (tpitg == 0) {
for (int i00 = 4 * (ne00 / 4); i00 < ne00; i00++) {
y_scalar[i00] = x_scalar[i00] * scale;
}
}
}
// function for calculate inner product between half a q4_0 block and 16 floats (yl), sumy is SUM(yl[i])