From patchwork Mon Feb 21 19:54:07 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Thomas Zimmermann X-Patchwork-Id: 544524 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B3654C43219 for ; Mon, 21 Feb 2022 19:54:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233278AbiBUTyi (ORCPT ); Mon, 21 Feb 2022 14:54:38 -0500 Received: from mxb-00190b01.gslb.pphosted.com ([23.128.96.19]:35662 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233249AbiBUTyh (ORCPT ); Mon, 21 Feb 2022 14:54:37 -0500 Received: from smtp-out2.suse.de (smtp-out2.suse.de [195.135.220.29]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F3B022B02 for ; Mon, 21 Feb 2022 11:54:14 -0800 (PST) Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by smtp-out2.suse.de (Postfix) with ESMTPS id AB5F91F391; Mon, 21 Feb 2022 19:54:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_rsa; t=1645473252; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N+GbnOGSeR3X9TVxFGABxV5nEPCZ3RUvOlA//TY0ScI=; b=KL9xTWa1qru2pt/2o5NaYPAF31VtzobhtB4DCKcO46MHYMtLVJ9v1JQXAsRi4qNCWee/Ax +uo2mVa124/nuZ9UKq0lhZyRwC9XAhS2q9hIfc7S2JQghiyuteSwpDy+mGpth33T7vQMDy fK4i19EYCSEG6iQAnN3mJEy3WL6IC7w= DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=suse.de; s=susede2_ed25519; t=1645473252; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=N+GbnOGSeR3X9TVxFGABxV5nEPCZ3RUvOlA//TY0ScI=; b=GqcygEyQxF2VAfckJt5rPpSClujgj9i4k5IdxZzJXKRB/FpAHBrWCZyQawDX3bv3bNdjy/ +VxWAvwHc4zDo5AA== Received: from imap2.suse-dmz.suse.de (imap2.suse-dmz.suse.de [192.168.254.74]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (P-521) server-digest SHA512) (No client certificate requested) by imap2.suse-dmz.suse.de (Postfix) with ESMTPS id 7615113BA4; Mon, 21 Feb 2022 19:54:12 +0000 (UTC) Received: from dovecot-director2.suse.de ([192.168.254.65]) by imap2.suse-dmz.suse.de with ESMTPSA id ENnhG+TtE2KVPwAAMHmgww (envelope-from ); Mon, 21 Feb 2022 19:54:12 +0000 From: Thomas Zimmermann To: daniel@ffwll.ch, deller@gmx.de, javierm@redhat.com, geert@linux-m68k.org, sam@ravnborg.org, kraxel@redhat.com Cc: dri-devel@lists.freedesktop.org, linux-fbdev@vger.kernel.org, Thomas Zimmermann Subject: [PATCH v2 2/5] fbdev: Improve performance of sys_imageblit() Date: Mon, 21 Feb 2022 20:54:07 +0100 Message-Id: <20220221195410.9172-3-tzimmermann@suse.de> X-Mailer: git-send-email 2.35.1 In-Reply-To: <20220221195410.9172-1-tzimmermann@suse.de> References: <20220221195410.9172-1-tzimmermann@suse.de> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Improve the performance of sys_imageblit() by manually unrolling the inner blitting loop and moving some invariants out. The compiler failed to do this automatically. The resulting binary code was even slower than the cfb_imageblit() helper, which uses the same algorithm, but operates on I/O memory. A microbenchmark measures the average number of CPU cycles for sys_imageblit() after a stabilizing period of a few minutes (i7-4790, FullHD, simpledrm, kernel with debugging). The value for CFB is given as a reference. sys_imageblit(), new: 25934 cycles sys_imageblit(), old: 35944 cycles cfb_imageblit(): 30566 cycles In the optimized case, sys_imageblit() is now ~30% faster than before and ~20% faster than cfb_imageblit(). v2: * move switch out of inner loop (Gerd) * remove test for alignment of dst1 (Sam) Signed-off-by: Thomas Zimmermann Reviewed-by: Javier Martinez Canillas Acked-by: Sam Ravnborg --- drivers/video/fbdev/core/sysimgblt.c | 49 +++++++++++++++++++++------- 1 file changed, 38 insertions(+), 11 deletions(-) diff --git a/drivers/video/fbdev/core/sysimgblt.c b/drivers/video/fbdev/core/sysimgblt.c index a4d05b1b17d7..722c327a381b 100644 --- a/drivers/video/fbdev/core/sysimgblt.c +++ b/drivers/video/fbdev/core/sysimgblt.c @@ -188,23 +188,29 @@ static void fast_imageblit(const struct fb_image *image, struct fb_info *p, { u32 fgx = fgcolor, bgx = bgcolor, bpp = p->var.bits_per_pixel; u32 ppw = 32/bpp, spitch = (image->width + 7)/8; - u32 bit_mask, end_mask, eorx, shift; + u32 bit_mask, eorx; const char *s = image->data, *src; u32 *dst; - const u32 *tab = NULL; + const u32 *tab; + size_t tablen; + u32 colortab[16]; int i, j, k; switch (bpp) { case 8: tab = fb_be_math(p) ? cfb_tab8_be : cfb_tab8_le; + tablen = 16; break; case 16: tab = fb_be_math(p) ? cfb_tab16_be : cfb_tab16_le; + tablen = 4; break; case 32: - default: tab = cfb_tab32; + tablen = 2; break; + default: + return; } for (i = ppw-1; i--; ) { @@ -218,19 +224,40 @@ static void fast_imageblit(const struct fb_image *image, struct fb_info *p, eorx = fgx ^ bgx; k = image->width/ppw; + for (i = 0; i < tablen; ++i) + colortab[i] = (tab[i] & eorx) ^ bgx; + for (i = image->height; i--; ) { dst = dst1; - shift = 8; src = s; - for (j = k; j--; ) { - shift -= ppw; - end_mask = tab[(*src >> shift) & bit_mask]; - *dst++ = (end_mask & eorx) ^ bgx; - if (!shift) { - shift = 8; - src++; + switch (ppw) { + case 4: /* 8 bpp */ + for (j = k; j; j -= 2, ++src) { + *dst++ = colortab[(*src >> 4) & bit_mask]; + *dst++ = colortab[(*src >> 0) & bit_mask]; + } + break; + case 2: /* 16 bpp */ + for (j = k; j; j -= 4, ++src) { + *dst++ = colortab[(*src >> 6) & bit_mask]; + *dst++ = colortab[(*src >> 4) & bit_mask]; + *dst++ = colortab[(*src >> 2) & bit_mask]; + *dst++ = colortab[(*src >> 0) & bit_mask]; + } + break; + case 1: /* 32 bpp */ + for (j = k; j; j -= 8, ++src) { + *dst++ = colortab[(*src >> 7) & bit_mask]; + *dst++ = colortab[(*src >> 6) & bit_mask]; + *dst++ = colortab[(*src >> 5) & bit_mask]; + *dst++ = colortab[(*src >> 4) & bit_mask]; + *dst++ = colortab[(*src >> 3) & bit_mask]; + *dst++ = colortab[(*src >> 2) & bit_mask]; + *dst++ = colortab[(*src >> 1) & bit_mask]; + *dst++ = colortab[(*src >> 0) & bit_mask]; } + break; } dst1 += p->fix.line_length; s += spitch;