Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030286AbVIVUAI (ORCPT ); Thu, 22 Sep 2005 16:00:08 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030303AbVIVUAH (ORCPT ); Thu, 22 Sep 2005 16:00:07 -0400 Received: from e33.co.us.ibm.com ([32.97.110.151]:37523 "EHLO e33.co.us.ibm.com") by vger.kernel.org with ESMTP id S1030286AbVIVUAB (ORCPT ); Thu, 22 Sep 2005 16:00:01 -0400 Subject: [RFC][PATCH 2/2] Reduced NTP rework (part 2) From: john stultz To: Roman Zippel Cc: lkml , Thomas Gleixner , George Anzinger , Ulrich Windl In-Reply-To: <1127419120.8195.7.camel@cog.beaverton.ibm.com> References: <1127419120.8195.7.camel@cog.beaverton.ibm.com> Content-Type: text/plain Date: Thu, 22 Sep 2005 12:59:58 -0700 Message-Id: <1127419198.8195.10.camel@cog.beaverton.ibm.com> Mime-Version: 1.0 X-Mailer: Evolution 2.2.3 (2.2.3-2.fc4) Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 6840 Lines: 241 Roman, All, Here is the second of two patches which try a minimized version of my ntp rework patches. This patch further changes the interrupt time NTP code, breaking out the leapsecond processing and introduces an accessor to a shifted ppm adjustment value. Again, this patch should not affect the existing behavior, but just separate the logical functionality so it can be re-used by my timeofday patches. thanks -john linux-2.6.14-rc2_timeofday-ntp-part2_B6test.patch ============================================ diff --git a/kernel/timer.c b/kernel/timer.c --- a/kernel/timer.c +++ b/kernel/timer.c @@ -620,6 +620,78 @@ static long time_adj; /* tick adjust ( long time_reftime; /* time at last adjustment (s) */ long time_adjust; long time_next_adjust; +long time_adjust_step; /* per tick time_adjust step */ + +long total_sppm; /* shifted ppm sum of all NTP adjustments */ +long offset_adj_ppm; +long tick_adj_ppm; +long singleshot_adj_ppm; + +#define MAX_SINGLESHOT_ADJ 500 /* (ppm) */ +#define SEC_PER_DAY 86400 + +/** + * ntp_leapsecond - NTP leapsecond processing code. + * now: the current time + * + * Returns the number of seconds (-1, 0, or 1) that + * should be added to the current time to properly + * adjust for leapseconds. + */ +int ntp_leapsecond(struct timespec now) +{ + /* + * Leap second processing. If in leap-insert state at + * the end of the day, the system clock is set back one + * second; if in leap-delete state, the system clock is + * set ahead one second. + */ + static time_t leaptime = 0; + + switch (time_state) { + + case TIME_OK: + if (time_status & STA_INS) + time_state = TIME_INS; + else if (time_status & STA_DEL) + time_state = TIME_DEL; + + /* calculate end of today (23:59:59)*/ + leaptime = now.tv_sec + SEC_PER_DAY - + (now.tv_sec % SEC_PER_DAY) - 1; + break; + + case TIME_INS: + /* Once we are at (or past) leaptime, insert the second */ + if (now.tv_sec >= leaptime) { + time_state = TIME_OOP; + printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n"); + return -1; + } + break; + + case TIME_DEL: + /* Once we are at (or past) leaptime, delete the second */ + if (now.tv_sec >= leaptime) { + time_state = TIME_WAIT; + printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n"); + return 1; + } + break; + + case TIME_OOP: + /* Wait for the end of the leap second*/ + if (now.tv_sec > (leaptime + 1)) + time_state = TIME_WAIT; + time_state = TIME_WAIT; + break; + + case TIME_WAIT: + if (!(time_status & (STA_INS | STA_DEL))) + time_state = TIME_OK; + } + return 0; +} /* * this routine handles the overflow of the microsecond field @@ -642,59 +714,6 @@ static void second_overflow(void) } /* - * Leap second processing. If in leap-insert state at - * the end of the day, the system clock is set back one - * second; if in leap-delete state, the system clock is - * set ahead one second. The microtime() routine or - * external clock driver will insure that reported time - * is always monotonic. The ugly divides should be - * replaced. - */ - switch (time_state) { - - case TIME_OK: - if (time_status & STA_INS) - time_state = TIME_INS; - else if (time_status & STA_DEL) - time_state = TIME_DEL; - break; - - case TIME_INS: - if (xtime.tv_sec % 86400 == 0) { - xtime.tv_sec--; - wall_to_monotonic.tv_sec++; - /* The timer interpolator will make time change gradually instead - * of an immediate jump by one second. - */ - time_interpolator_update(-NSEC_PER_SEC); - time_state = TIME_OOP; - clock_was_set(); - printk(KERN_NOTICE "Clock: inserting leap second 23:59:60 UTC\n"); - } - break; - - case TIME_DEL: - if ((xtime.tv_sec + 1) % 86400 == 0) { - xtime.tv_sec++; - wall_to_monotonic.tv_sec--; - /* Use of time interpolator for a gradual change of time */ - time_interpolator_update(NSEC_PER_SEC); - time_state = TIME_WAIT; - clock_was_set(); - printk(KERN_NOTICE "Clock: deleting leap second 23:59:59 UTC\n"); - } - break; - - case TIME_OOP: - time_state = TIME_WAIT; - break; - - case TIME_WAIT: - if (!(time_status & (STA_INS | STA_DEL))) - time_state = TIME_OK; - } - - /* * Compute the phase adjustment for the next second. In * PLL mode, the offset is reduced by a fixed factor * times the time constant. In FLL mode the offset is @@ -711,6 +730,13 @@ static void second_overflow(void) time_offset -= ltemp; time_adj = ltemp << (SHIFT_SCALE - SHIFT_HZ - SHIFT_UPDATE); + offset_adj_ppm = shift_right(ltemp, SHIFT_UPDATE); /* ppm */ + + /* first calculate usec/user_tick offset */ + tick_adj_ppm = ((USEC_PER_SEC + USER_HZ/2)/USER_HZ) - tick_usec; + /* multiply by user_hz to get usec/sec => ppm */ + tick_adj_ppm *= USER_HZ; + /* * Compute the frequency estimate and additional phase * adjustment due to frequency error for the next @@ -742,9 +768,17 @@ static void second_overflow(void) #endif } -long time_adjust_step; -static void ntp_advance(unsigned long interval_ns) +/** + * ntp_get_ppm_adjustment - Returns Shifted PPM adjustment + * + */ +long ntp_get_ppm_adjustment(void) +{ + return total_sppm; +} + +void ntp_advance(unsigned long interval_ns) { static unsigned long interval_sum; @@ -772,6 +806,7 @@ static void ntp_advance(unsigned long in } interval_ns -= tick_nsec; } + singleshot_adj_ppm = time_adjust_step*(1000000/HZ); /* usec/tick => ppm */ /* Changes by adjtime() do not take effect till next tick. */ if (time_next_adjust) { @@ -783,6 +818,12 @@ static void ntp_advance(unsigned long in interval_sum -= NSEC_PER_SEC; second_overflow(); } + + /* calculate the total continuous ppm adjustment */ + total_sppm = time_freq; /* already shifted by SHIFT_USEC */ + total_sppm += offset_adj_ppm << SHIFT_USEC; + total_sppm += tick_adj_ppm << SHIFT_USEC; + total_sppm += singleshot_adj_ppm << SHIFT_USEC; } /* @@ -817,8 +858,18 @@ static void update_wall_time(unsigned lo xtime.tv_nsec += delta_nsec; if (xtime.tv_nsec >= 1000000000) { + int leapsecond; xtime.tv_nsec -= 1000000000; xtime.tv_sec++; + /* process leapsecond */ + leapsecond = ntp_leapsecond(xtime); + if (leapsecond) { + xtime.tv_sec += leapsecond; + wall_to_monotonic.tv_sec -= leapsecond; + /* Use of time interpolator for a gradual change of time */ + time_interpolator_update(leapsecond*NSEC_PER_SEC); + clock_was_set(); + } } ntp_advance(tick_nsec); time_interpolator_update(delta_nsec); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/