From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49311) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1dBfyE-0004GR-Ei for qemu-devel@nongnu.org; Fri, 19 May 2017 07:21:23 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1dBfyA-0000sh-Ss for qemu-devel@nongnu.org; Fri, 19 May 2017 07:21:22 -0400 Received: from mail-wr0-x243.google.com ([2a00:1450:400c:c0c::243]:36315) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1dBfyA-0000sK-NM for qemu-devel@nongnu.org; Fri, 19 May 2017 07:21:18 -0400 Received: by mail-wr0-x243.google.com with SMTP id v42so2612876wrc.3 for ; Fri, 19 May 2017 04:21:18 -0700 (PDT) Sender: Paolo Bonzini From: Paolo Bonzini Date: Fri, 19 May 2017 13:20:53 +0200 Message-Id: <1495192872-27667-2-git-send-email-pbonzini@redhat.com> In-Reply-To: <1495192872-27667-1-git-send-email-pbonzini@redhat.com> References: <1495192872-27667-1-git-send-email-pbonzini@redhat.com> Subject: [Qemu-devel] [PULL 01/20] mc146818rtc: update periodic timer only if it is needed List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Xiao Guangrong From: Xiao Guangrong Currently, the timer is updated whenever RegA or RegB is written even if the periodic timer related configuration is not changed This patch optimizes it slightly to make the update happen only if its period or enable-status is changed, also later patches are depend on this optimization Signed-off-by: Xiao Guangrong Message-Id: <20170510083259.3900-2-xiaoguangrong@tencent.com> Signed-off-by: Paolo Bonzini --- hw/timer/mc146818rtc.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/hw/timer/mc146818rtc.c b/hw/timer/mc146818rtc.c index 93de3e1..7d78391 100644 --- a/hw/timer/mc146818rtc.c +++ b/hw/timer/mc146818rtc.c @@ -391,6 +391,7 @@ static void cmos_ioport_write(void *opaque, hwaddr addr, uint64_t data, unsigned size) { RTCState *s = opaque; + bool update_periodic_timer; if ((addr & 1) == 0) { s->cmos_index = data & 0x7f; @@ -423,6 +424,8 @@ static void cmos_ioport_write(void *opaque, hwaddr addr, } break; case RTC_REG_A: + update_periodic_timer = (s->cmos_data[RTC_REG_A] ^ data) & 0x0f; + if ((data & 0x60) == 0x60) { if (rtc_running(s)) { rtc_update_time(s); @@ -445,10 +448,17 @@ static void cmos_ioport_write(void *opaque, hwaddr addr, /* UIP bit is read only */ s->cmos_data[RTC_REG_A] = (data & ~REG_A_UIP) | (s->cmos_data[RTC_REG_A] & REG_A_UIP); - periodic_timer_update(s, qemu_clock_get_ns(rtc_clock)); + + if (update_periodic_timer) { + periodic_timer_update(s, qemu_clock_get_ns(rtc_clock)); + } + check_update_timer(s); break; case RTC_REG_B: + update_periodic_timer = (s->cmos_data[RTC_REG_B] ^ data) + & REG_B_PIE; + if (data & REG_B_SET) { /* update cmos to when the rtc was stopping */ if (rtc_running(s)) { @@ -475,7 +485,11 @@ static void cmos_ioport_write(void *opaque, hwaddr addr, qemu_irq_lower(s->irq); } s->cmos_data[RTC_REG_B] = data; - periodic_timer_update(s, qemu_clock_get_ns(rtc_clock)); + + if (update_periodic_timer) { + periodic_timer_update(s, qemu_clock_get_ns(rtc_clock)); + } + check_update_timer(s); break; case RTC_REG_C: -- 1.8.3.1