From 3df9c9d5c2d54a41711f44c6afed1abd0c878297 Mon Sep 17 00:00:00 2001
From: Andreas Kloeckner <inform@tiker.net>
Date: Tue, 31 Jul 2012 00:49:53 -0500
Subject: [PATCH] Be smarter about finding work partitions in the scan.
---
pyopencl/scan.py | 17 +++++++++++------
1 file changed, 11 insertions(+), 6 deletions(-)
diff --git a/pyopencl/scan.py b/pyopencl/scan.py
index 526f679c..03bfef17 100644
--- a/pyopencl/scan.py
+++ b/pyopencl/scan.py
@@ -988,8 +988,10 @@ class GenericScanKernel(_GenericScanKernelBase):
# (about the widest vector a CPU can support, also taking
# into account that CPUs don't hide latency by large work groups
max_scan_wg_size = 16
+ wg_size_multiples = 16
else:
max_scan_wg_size = min(dev.max_work_group_size for dev in self.devices)
+ wg_size_multiples = 64
avail_local_mem = min(
dev.local_mem_size
@@ -998,14 +1000,17 @@ class GenericScanKernel(_GenericScanKernelBase):
# k_group_size should be a power of two because of in-kernel
# division by that number.
- k_group_size = 128
+ solutions = []
+ for k_exp in range(0, 7):
+ for wg_size in range(wg_size_multiples, max_scan_wg_size+1,
+ wg_size_multiples):
- while (
- self.get_local_mem_use(
- max_scan_wg_size, k_group_size) + 256 > avail_local_mem):
- k_group_size //= 2
+ k_group_size = 2**k_exp
+ if (self.get_local_mem_use(
+ wg_size, k_group_size) + 256 <= avail_local_mem):
+ solutions.append((wg_size*k_group_size, k_group_size, wg_size))
- assert k_group_size > 1
+ _, k_group_size, max_scan_wg_size = max(solutions)
while True:
candidate_scan_info = self.build_scan_kernel(
--
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