From patchwork Sun Jun 27 09:09:56 2010 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marko Ristola X-Patchwork-Id: 108249 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by demeter.kernel.org (8.14.4/8.14.3) with ESMTP id o5R9AHSS001993 for ; Sun, 27 Jun 2010 09:10:17 GMT Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753454Ab0F0JKE (ORCPT ); Sun, 27 Jun 2010 05:10:04 -0400 Received: from emh01.mail.saunalahti.fi ([62.142.5.107]:48033 "EHLO emh01.mail.saunalahti.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752701Ab0F0JKB (ORCPT ); Sun, 27 Jun 2010 05:10:01 -0400 Received: from saunalahti-vams (vs3-11.mail.saunalahti.fi [62.142.5.95]) by emh01-2.mail.saunalahti.fi (Postfix) with SMTP id 8A2E28C413 for ; Sun, 27 Jun 2010 12:09:59 +0300 (EEST) Received: from emh07.mail.saunalahti.fi ([62.142.5.117]) by vs3-11.mail.saunalahti.fi ([62.142.5.95]) with SMTP (gateway) id A010AB849F2; Sun, 27 Jun 2010 12:09:59 +0300 Received: from kuusi.koti (a88-114-153-83.elisa-laajakaista.fi [88.114.153.83]) by emh07.mail.saunalahti.fi (Postfix) with ESMTP id 595951C6382; Sun, 27 Jun 2010 12:09:57 +0300 (EEST) Message-ID: <4C271564.2020501@kolumbus.fi> Date: Sun, 27 Jun 2010 12:09:56 +0300 From: Marko Ristola User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.10) Gecko/20100621 Fedora/3.0.5-1.fc13 Lightning/1.0b2pre Thunderbird/3.0.5 MIME-Version: 1.0 To: Marko Ristola CC: Linux Media Mailing List Subject: Re: [PATCH] Avoid unnecessary data copying inside dvb_dmx_swfilter_204() function References: <4C2615FB.2000805@kolumbus.fi> In-Reply-To: <4C2615FB.2000805@kolumbus.fi> X-Antivirus: VAMS Sender: linux-media-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-media@vger.kernel.org X-Greylist: IP, sender and recipient auto-whitelisted, not delayed by milter-greylist-4.2.3 (demeter.kernel.org [140.211.167.41]); Sun, 27 Jun 2010 09:10:17 +0000 (UTC) diff --git a/drivers/media/dvb/dvb-core/dvb_demux.c b/drivers/media/dvb/dvb-core/dvb_demux.c index 977ddba..2ddaaaa 100644 --- a/drivers/media/dvb/dvb-core/dvb_demux.c +++ b/drivers/media/dvb/dvb-core/dvb_demux.c @@ -478,95 +478,78 @@ void dvb_dmx_swfilter_packets(struct dvb_demux *demux, const u8 *buf, EXPORT_SYMBOL(dvb_dmx_swfilter_packets); -void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count) +static inline int findNextSyncByte(const u8 *buf, int pos, size_t count, const int pktsize) +{ + while(likely(pos < count)) { + if (likely(buf[pos] == 0x47 || (pktsize == 204 && buf[pos] == 0xB8))) + break; + pos++; + } + + return pos; +} + +/* pktsize must be either 204 or 188. If pktsize is 204, 0xB8 must be accepted for SYNC byte too, but then convert it into 0x47. + * Designed pktsize so, that compiler would remove 204 related code during inlining. */ +static inline void _dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count, const int pktsize) { int p = 0, i, j; + const u8 *q; spin_lock(&demux->lock); - if (demux->tsbufp) { + if (likely(demux->tsbufp)) { /* tsbuf[0] is now 0x47. */ i = demux->tsbufp; - j = 188 - i; - if (count < j) { + j = pktsize - i; + if (unlikely(count < j)) { memcpy(&demux->tsbuf[i], buf, count); demux->tsbufp += count; goto bailout; } memcpy(&demux->tsbuf[i], buf, j); - if (demux->tsbuf[0] == 0x47) + if (likely(demux->tsbuf[0] == 0x47)) /* double check */ dvb_dmx_swfilter_packet(demux, demux->tsbuf); demux->tsbufp = 0; p += j; } - while (p < count) { - if (buf[p] == 0x47) { - if (count - p >= 188) { - dvb_dmx_swfilter_packet(demux, &buf[p]); - p += 188; - } else { - i = count - p; - memcpy(demux->tsbuf, &buf[p], i); - demux->tsbufp = i; - goto bailout; - } - } else - p++; + while (likely((p = findNextSyncByte(buf, p, count, pktsize)) < count)) { + if (unlikely(count - p < pktsize)) + break; + + q = &buf[p]; + + if (unlikely(pktsize == 204 && (*q == 0xB8))) { + memcpy(demux->tsbuf, q, 188); + demux->tsbuf[0] = 0x47; + q = demux->tsbuf; + } + dvb_dmx_swfilter_packet(demux, q); + p += pktsize; + } + + i = count - p; + if (likely(i)) { + memcpy(demux->tsbuf, &buf[p], i); + demux->tsbufp = i; + if (unlikely(pktsize == 204 && demux->tsbuf[0] == 0xB8)) + demux->tsbuf[0] = 0x47; } bailout: spin_unlock(&demux->lock); } +void dvb_dmx_swfilter(struct dvb_demux *demux, const u8 *buf, size_t count) +{ + _dvb_dmx_swfilter(demux, buf, count, 188); +} + EXPORT_SYMBOL(dvb_dmx_swfilter); void dvb_dmx_swfilter_204(struct dvb_demux *demux, const u8 *buf, size_t count) { - int p = 0, i, j; - u8 tmppack[188]; - - spin_lock(&demux->lock); - - if (demux->tsbufp) { - i = demux->tsbufp; - j = 204 - i; - if (count < j) { - memcpy(&demux->tsbuf[i], buf, count); - demux->tsbufp += count; - goto bailout; - } - memcpy(&demux->tsbuf[i], buf, j); - if ((demux->tsbuf[0] == 0x47) || (demux->tsbuf[0] == 0xB8)) { - memcpy(tmppack, demux->tsbuf, 188); - if (tmppack[0] == 0xB8) - tmppack[0] = 0x47; - dvb_dmx_swfilter_packet(demux, tmppack); - } - demux->tsbufp = 0; - p += j; - } - - while (p < count) { - if ((buf[p] == 0x47) || (buf[p] == 0xB8)) { - if (count - p >= 204) { - memcpy(tmppack, &buf[p], 188); - if (tmppack[0] == 0xB8) - tmppack[0] = 0x47; - dvb_dmx_swfilter_packet(demux, tmppack); - p += 204; - } else { - i = count - p; - memcpy(demux->tsbuf, &buf[p], i); - demux->tsbufp = i; - goto bailout; - } - } else { - p++;