From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dave Airlie Subject: [PATCH] drm: micro optimise cache flushing Date: Wed, 19 Sep 2012 11:12:41 +1000 Message-ID: <1348017161-27475-1-git-send-email-airlied@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mx1.redhat.com (mx1.redhat.com [209.132.183.28]) by gabe.freedesktop.org (Postfix) with ESMTP id E27E59E75D for ; Tue, 18 Sep 2012 18:12:43 -0700 (PDT) Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id q8J1Chr5003195 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 18 Sep 2012 21:12:43 -0400 Received: from prime.bne.redhat.com (dhcp-40-183.bne.redhat.com [10.64.40.183]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id q8J1Cftv025698 for ; Tue, 18 Sep 2012 21:12:42 -0400 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org Errors-To: dri-devel-bounces+sf-dri-devel=m.gmane.org@lists.freedesktop.org To: dri-devel@lists.freedesktop.org List-Id: dri-devel@lists.freedesktop.org From: Dave Airlie We hit this a lot with i915 and although we'd like to engineer things to hit it a lot less, this commit at least makes it consume a few less cycles. from something containing movzwl 0x0(%rip),%r10d to add %r8,%rdx I only noticed it while using perf to profile something else. Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_cache.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/gpu/drm/drm_cache.c b/drivers/gpu/drm/drm_cache.c index 08758e0..3dbc7f1 100644 --- a/drivers/gpu/drm/drm_cache.c +++ b/drivers/gpu/drm/drm_cache.c @@ -37,12 +37,13 @@ drm_clflush_page(struct page *page) { uint8_t *page_virtual; unsigned int i; + const int size = boot_cpu_data.x86_clflush_size; if (unlikely(page == NULL)) return; page_virtual = kmap_atomic(page); - for (i = 0; i < PAGE_SIZE; i += boot_cpu_data.x86_clflush_size) + for (i = 0; i < PAGE_SIZE; i += size) clflush(page_virtual + i); kunmap_atomic(page_virtual); } -- 1.7.12