From nobody Tue Dec 16 21:00:24 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6FD54BE7F for ; Thu, 13 Jun 2024 00:32:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718238724; cv=none; b=F5UJqyVm//sDDUe6d7Faj3Q3p6K5dGILY7dHg6Ag64olBtNr7MqWxU9FUaef9yRf9q9qzyUPRH4TE9TKt6NaATstDIJLn+JXOGuD8qWzLWibvsmjgMRx3fML6QWWyPYBIWs0ECFBKwaPS1f6krC1wUlD3a44DuhlWzLmxFqM3Sc= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1718238724; c=relaxed/simple; bh=CzUcaUEwid9QP2s+ip8EXYQc/owNHwh0AeSROulmsmQ=; h=From:To:Cc:Subject:Date:Message-ID:MIME-Version; b=RYAbzm9OOxNh172sfo+WouRtBc4kI7/wll1wDCTiRH1O7AVIZzj4xLdUsTZvnNLvAULdE7YaRn4jNS4+w8i2S+3qp1lhpZJ9vk/9Ew/xiNef/2jckDlieH1OQ3l3hzhaS9H/2tKNzm5dh0hJ4TeSfNG+GsxEGmS/5U+qzou51xc= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=RP3f3zHl; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="RP3f3zHl" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D945DC4AF1D; Thu, 13 Jun 2024 00:32:02 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1718238723; bh=CzUcaUEwid9QP2s+ip8EXYQc/owNHwh0AeSROulmsmQ=; h=From:To:Cc:Subject:Date:From; b=RP3f3zHljgB69meR2mgyyG8IzWJoRo8SVqkFr5jfvu+xVTg/9RN/q30+sHnDWuMxl cOlOAXD7rIeLJKCCvtMVWLt31QrLWRSCcAch7K95GAH7Mnc8G3A4wMkATg977X20iB B+MLf8f0KbV/kqBoxlbbN6+gSMztY/CT1fFGniRjB+HV6/iIiM38HY0y0dxQJDP2Tn HCsE9Pp9aryZMOnBs/QgAmmtmWj72asyKJPsBCxG8LAtAv8LJPLxo5rrd0QtPjJBR0 RlRcvvz+zp5UFD2kSU2GUzfqgLdpXX3xs/Egop2Q/h6r7oizsqbu7GbHCqiuDGHOFA 3QXMDfaZ6ZFNg== From: Jisheng Zhang To: Catalin Marinas , Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: [PATCH] arm64/lib: copy_page: s/stnp/stp Date: Thu, 13 Jun 2024 08:18:12 +0800 Message-ID: <20240613001812.2141-1-jszhang@kernel.org> X-Mailer: git-send-email 2.43.0 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" stnp performs non-temporal store, give a hints to the memory system that caching is not useful for this data. But the scenario where copy_page() used may not have this implication, although I must admit there's such case where stnp helps performance(good). In this good case, we can rely on the HW write streaming mechanism in some implementations such as cortex-a55 to detect the case and take actions. testing with https://github.com/apinski-cavium/copy_page_benchmark this patch can reduce the time by about 3% on cortex-a55 platforms. Signed-off-by: Jisheng Zhang --- arch/arm64/lib/copy_page.S | 32 ++++++++++++++++---------------- 1 file changed, 16 insertions(+), 16 deletions(-) diff --git a/arch/arm64/lib/copy_page.S b/arch/arm64/lib/copy_page.S index 6a56d7cf309d..4c74fe2d8bd6 100644 --- a/arch/arm64/lib/copy_page.S +++ b/arch/arm64/lib/copy_page.S @@ -32,21 +32,21 @@ SYM_FUNC_START(__pi_copy_page) 1: tst x0, #(PAGE_SIZE - 1) =20 - stnp x2, x3, [x0, #-256] + stp x2, x3, [x0, #-256] ldp x2, x3, [x1] - stnp x4, x5, [x0, #16 - 256] + stp x4, x5, [x0, #16 - 256] ldp x4, x5, [x1, #16] - stnp x6, x7, [x0, #32 - 256] + stp x6, x7, [x0, #32 - 256] ldp x6, x7, [x1, #32] - stnp x8, x9, [x0, #48 - 256] + stp x8, x9, [x0, #48 - 256] ldp x8, x9, [x1, #48] - stnp x10, x11, [x0, #64 - 256] + stp x10, x11, [x0, #64 - 256] ldp x10, x11, [x1, #64] - stnp x12, x13, [x0, #80 - 256] + stp x12, x13, [x0, #80 - 256] ldp x12, x13, [x1, #80] - stnp x14, x15, [x0, #96 - 256] + stp x14, x15, [x0, #96 - 256] ldp x14, x15, [x1, #96] - stnp x16, x17, [x0, #112 - 256] + stp x16, x17, [x0, #112 - 256] ldp x16, x17, [x1, #112] =20 add x0, x0, #128 @@ -54,14 +54,14 @@ SYM_FUNC_START(__pi_copy_page) =20 b.ne 1b =20 - stnp x2, x3, [x0, #-256] - stnp x4, x5, [x0, #16 - 256] - stnp x6, x7, [x0, #32 - 256] - stnp x8, x9, [x0, #48 - 256] - stnp x10, x11, [x0, #64 - 256] - stnp x12, x13, [x0, #80 - 256] - stnp x14, x15, [x0, #96 - 256] - stnp x16, x17, [x0, #112 - 256] + stp x2, x3, [x0, #-256] + stp x4, x5, [x0, #16 - 256] + stp x6, x7, [x0, #32 - 256] + stp x8, x9, [x0, #48 - 256] + stp x10, x11, [x0, #64 - 256] + stp x12, x13, [x0, #80 - 256] + stp x14, x15, [x0, #96 - 256] + stp x16, x17, [x0, #112 - 256] =20 ret SYM_FUNC_END(__pi_copy_page) --=20 2.43.0