Attachment 49752 Details for Bug 37922 – Enable xfer only when we need it to save power

[patch] Enable xfer only when we need it to save power

0001-drm-nv50-ctxprog-enable-xfer-only-when-we-need-it-to.patch (text/plain), 1.83 KB, created by Martin Peres on 2011-07-30 14:18:52 UTC

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Creator: Martin Peres

Created: 2011-07-30 14:18:52 UTC

Size: 1.83 KB

patch

obsolete

>From 2f2a89723681eb86e83ca353fcee64d39b21d225 Mon Sep 17 00:00:00 2001
>From: Martin Peres <martin.peres@ensi-bourges.fr>
>Date: Sat, 30 Jul 2011 23:08:45 +0200
>Subject: [PATCH] drm/nv50/ctxprog: enable xfer only when we need it to save
> power
>
>This patch adds instructions to ctxprog and by doing, impact context-switching performance.
>My testcase showed a 1% performance cost using glxgears that is a context-switch bound application.
>
>Please test and report bugs/performance/power/other.
>---
> drivers/gpu/drm/nouveau/nv50_grctx.c |    5 +++++
> 1 files changed, 5 insertions(+), 0 deletions(-)
>
>diff --git a/drivers/gpu/drm/nouveau/nv50_grctx.c b/drivers/gpu/drm/nouveau/nv50_grctx.c
>index e04fb44..d05c2c3 100644
>--- a/drivers/gpu/drm/nouveau/nv50_grctx.c
>+++ b/drivers/gpu/drm/nouveau/nv50_grctx.c
>@@ -40,6 +40,9 @@
> #define CP_FLAG_UNK0B                 ((0 * 32) + 0xb)
> #define CP_FLAG_UNK0B_CLEAR           0
> #define CP_FLAG_UNK0B_SET             1
>+#define CP_FLAG_XFER_SWITCH           ((0 * 32) + 0xe)
>+#define CP_FLAG_XFER_SWITCH_DISABLE   0
>+#define CP_FLAG_XFER_SWITCH_ENABLE    1
> #define CP_FLAG_STATE                 ((0 * 32) + 0x1c)
> #define CP_FLAG_STATE_STOPPED         0
> #define CP_FLAG_STATE_RUNNING         1
>@@ -199,6 +202,7 @@ nv50_grctx_init(struct nouveau_grctx *ctx)
> 	}
> 
> 	cp_set (ctx, STATE, RUNNING);
>+	cp_set (ctx, XFER_SWITCH, ENABLE);
> 	/* decide whether we're loading/unloading the context */
> 	cp_bra (ctx, AUTO_SAVE, PENDING, cp_setup_save);
> 	cp_bra (ctx, USER_SAVE, PENDING, cp_setup_save);
>@@ -265,6 +269,7 @@ nv50_grctx_init(struct nouveau_grctx *ctx)
> 	cp_name(ctx, cp_exit);
> 	cp_set (ctx, USER_SAVE, NOT_PENDING);
> 	cp_set (ctx, USER_LOAD, NOT_PENDING);
>+	cp_set (ctx, XFER_SWITCH, DISABLE);
> 	cp_set (ctx, STATE, STOPPED);
> 	cp_out (ctx, CP_END);
> 	ctx->ctxvals_pos += 0x400; /* padding... no idea why you need it */
>-- 
>1.7.6
>

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