Am 19.07.2014 14:37, schrieb Grigori Goronzy:
On 19.07.2014 13:57, Christian König wrote:
Yeah, I'm still playing a bit with this.
You need to consider the page directory size as well. If we have 4GB
address space (32bits) and 12bits in the page, 12bits in the page tables
then there are only 8bits for the page directory, right?
Now 8bits for the page directory means we have 256 entries with 8bytes
for each entry that makes 2048 bytes for the page directory. But since
we allocate 4096 bytes for the page directory anyway we could support
8GB address space as well.
Yes, that's right... good idea. Larger VM space should also help a bit
with fragmentation under memory pressure, right?
Only when the application really needs a lot of RAM. Twice as much
address space than memory should be perfectly sufficient in most cases.
How about the v2 I've just send out to the list? It also adjusts the
vm_size to a default of 8GB and let you get vm_block_sizes according to
the following table:
Looks good, I think.
Does that mean that I have you're rb on the v2 of the patch? A bit of
testing might be a good idea as well, cause I just hacked together the
patch in a bit spare time.
If all is well CC Alex as well, so he can replace the original patch
with the v2 in hist 3.17-wip branch.
Regards,
Christian.
vm_size vm_block_size
1GB = 9
2GB = 10
4GB = 11
8GB = 12
16GB = 12
32GB = 13
64GB = 13
128GB = 14
256GB = 14
512GB = 15
1TB = 15
Regards,
Christian.
Am 18.07.2014 22:03, schrieb Grigori Goronzy:
On 18.07.2014 11:38, Christian König wrote:
From: Christian König <christian.koenig@xxxxxxx>
Signed-off-by: Christian König <christian.koenig@xxxxxxx>
---
drivers/gpu/drm/radeon/radeon_device.c | 6 +++++-
drivers/gpu/drm/radeon/radeon_drv.c | 4 ++--
2 files changed, 7 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/radeon/radeon_device.c
b/drivers/gpu/drm/radeon/radeon_device.c
index 03686fa..a2960db 100644
--- a/drivers/gpu/drm/radeon/radeon_device.c
+++ b/drivers/gpu/drm/radeon/radeon_device.c
@@ -1077,7 +1077,11 @@ static void radeon_check_arguments(struct
radeon_device *rdev)
/* defines number of bits in page table versus page directory,
* a page is 4KB so we have 12 bits offset, minimum 9 bits in the
* page table and the remaining bits are in the page directory */
- if (radeon_vm_block_size < 9) {
+ if (radeon_vm_block_size == -1) {
+ radeon_vm_block_size = (ilog2(radeon_vm_size) + 10) / 2;
+ radeon_vm_block_size = max(radeon_vm_block_size, 9);
+
+ } else if (radeon_vm_block_size < 9) {
Hm, that automatic calculation seems strange. Is there any particular
reason why you haven chosen this? This will use vm_block_size=11 for
4096 MB VM space. I have used vm_block_size=12 with good results. This
manages 16 MB of VM space per page table, which seems reasonable. I also
see a noticeable CPU overhead reduction between 11 and 12.
Grigori
dev_warn(rdev->dev, "VM page table size (%d) to small\n",
radeon_vm_block_size);
radeon_vm_block_size = 9;
diff --git a/drivers/gpu/drm/radeon/radeon_drv.c
b/drivers/gpu/drm/radeon/radeon_drv.c
index cb14213..fef5320 100644
--- a/drivers/gpu/drm/radeon/radeon_drv.c
+++ b/drivers/gpu/drm/radeon/radeon_drv.c
@@ -174,7 +174,7 @@ int radeon_aspm = -1;
int radeon_runtime_pm = -1;
int radeon_hard_reset = 0;
int radeon_vm_size = 4096;
-int radeon_vm_block_size = 9;
+int radeon_vm_block_size = -1;
int radeon_deep_color = 0;
MODULE_PARM_DESC(no_wb, "Disable AGP writeback for scratch
registers");
@@ -246,7 +246,7 @@ module_param_named(hard_reset, radeon_hard_reset,
int, 0444);
MODULE_PARM_DESC(vm_size, "VM address space size in megabytes
(default 4GB)");
module_param_named(vm_size, radeon_vm_size, int, 0444);
-MODULE_PARM_DESC(vm_block_size, "VM page table size in bits
(default 9)");
+MODULE_PARM_DESC(vm_block_size, "VM page table size in bits (default
depending on vm_size)");
module_param_named(vm_block_size, radeon_vm_block_size, int, 0444);
MODULE_PARM_DESC(deep_color, "Deep Color support (1 = enable, 0 =
disable (default))");
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