Date: Thu, 13 Oct 2016 06:49:00 +0000 (UTC) From: Sepherosa Ziehau <sephe@FreeBSD.org> To: src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-stable@freebsd.org, svn-src-stable-10@freebsd.org Subject: svn commit: r307187 - stable/10/sys/dev/hyperv/utilities Message-ID: <201610130649.u9D6n0n6000266@repo.freebsd.org>
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Author: sephe Date: Thu Oct 13 06:49:00 2016 New Revision: 307187 URL: https://svnweb.freebsd.org/changeset/base/307187 Log: MFC 305111 hyperv/timesync: Rework time adjustment policy - By default, adjust time upon SYNC request. It can be disabled through hw.hvtimesync.ignore_sync_req. SYNC request will be sent by hypervisor the host is resumed, rebooted, etc. - By default, adjust time upon SAMPLE request, if there is 100ms difference between VM time and hypervisor time. This can be disabled through hw.hvtimesync.sample_drift. And nuke the unnecessary task, since channel callback is running in a Hyper-V taskqueue nowadays. Submitted by: YanZhe Chen <t-yachen microsoft com> Discussed with: Dexuan Cui <decui microsoft com>, Hongjiang Zhang <honzhan microsoft com>, sephe Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D7707 Modified: stable/10/sys/dev/hyperv/utilities/hv_timesync.c Directory Properties: stable/10/ (props changed) Modified: stable/10/sys/dev/hyperv/utilities/hv_timesync.c ============================================================================== --- stable/10/sys/dev/hyperv/utilities/hv_timesync.c Thu Oct 13 06:47:02 2016 (r307186) +++ stable/10/sys/dev/hyperv/utilities/hv_timesync.c Thu Oct 13 06:49:00 2016 (r307187) @@ -39,7 +39,7 @@ #include <sys/timetc.h> #include <sys/syscallsubr.h> #include <sys/systm.h> -#include <sys/taskqueue.h> +#include <sys/sysctl.h> #include <dev/hyperv/include/hyperv.h> #include <dev/hyperv/include/vmbus.h> @@ -52,11 +52,7 @@ #define HV_ICTIMESYNCFLAG_SYNC 1 #define HV_ICTIMESYNCFLAG_SAMPLE 2 #define HV_NANO_SEC_PER_SEC 1000000000 - -/* Time Sync data */ -typedef struct { - uint64_t data; -} time_sync_data; +#define HV_NANO_SEC_PER_MILLI_SEC 1000000 static const struct vmbus_ic_desc vmbus_timesync_descs[] = { { @@ -75,22 +71,43 @@ struct hv_ictimesync_data { uint8_t flags; } __packed; -typedef struct hv_timesync_sc { - hv_util_sc util_sc; - struct task task; - time_sync_data time_msg; -} hv_timesync_sc; +/* + * Globals + */ +SYSCTL_NODE(_hw, OID_AUTO, hvtimesync, CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, + "Hyper-V timesync interface"); + +/* Ignore the sync request when set to 1. */ +static int ignore_sync_req = 0; +SYSCTL_INT(_hw_hvtimesync, OID_AUTO, ignore_sync_req, CTLFLAG_RWTUN, + &ignore_sync_req, 0, + "Ignore the sync request when set to 1."); + +/* + * Trigger sample sync when drift exceeds threshold (ms). + * Ignore the sample request when set to 0. + */ +static int sample_drift = 100; +SYSCTL_INT(_hw_hvtimesync, OID_AUTO, sample_drift, CTLFLAG_RWTUN, + &sample_drift, 0, + "Threshold that makes sample request trigger the sync."); /** - * Set host time based on time sync message from host + * @brief Synchronize time with host after reboot, restore, etc. + * + * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM. + * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time + * message after the timesync channel is opened. Since the hv_utils module is + * loaded after hv_vmbus, the first message is usually missed. The other + * thing is, systime is automatically set to emulated hardware clock which may + * not be UTC time or in the same time zone. So, to override these effects, we + * use the first 50 time samples for initial system time setting. */ -static void -hv_set_host_time(void *context, int pending) +static inline +void hv_adj_guesttime(hv_util_sc *sc, uint64_t hosttime, uint8_t flags) { - hv_timesync_sc *softc = (hv_timesync_sc*)context; - uint64_t hosttime = softc->time_msg.data; struct timespec guest_ts, host_ts; - uint64_t host_tns; + uint64_t host_tns, guest_tns; int64_t diff; int error; @@ -99,37 +116,35 @@ hv_set_host_time(void *context, int pend host_ts.tv_nsec = (long)(host_tns%HV_NANO_SEC_PER_SEC); nanotime(&guest_ts); + guest_tns = guest_ts.tv_sec * HV_NANO_SEC_PER_SEC + guest_ts.tv_nsec; - diff = (int64_t)host_ts.tv_sec - (int64_t)guest_ts.tv_sec; + if ((flags & HV_ICTIMESYNCFLAG_SYNC) != 0 && ignore_sync_req == 0) { + if (bootverbose) { + device_printf(sc->ic_dev, "handle sync request " + "{host: %ju, guest: %ju}\n", + (uintmax_t)host_tns, (uintmax_t)guest_tns); + } - /* - * If host differs by 5 seconds then make the guest catch up - */ - if (diff > 5 || diff < -5) { error = kern_clock_settime(curthread, CLOCK_REALTIME, &host_ts); + return; } -} -/** - * @brief Synchronize time with host after reboot, restore, etc. - * - * ICTIMESYNCFLAG_SYNC flag bit indicates reboot, restore events of the VM. - * After reboot the flag ICTIMESYNCFLAG_SYNC is included in the first time - * message after the timesync channel is opened. Since the hv_utils module is - * loaded after hv_vmbus, the first message is usually missed. The other - * thing is, systime is automatically set to emulated hardware clock which may - * not be UTC time or in the same time zone. So, to override these effects, we - * use the first 50 time samples for initial system time setting. - */ -static inline -void hv_adj_guesttime(hv_timesync_sc *sc, uint64_t hosttime, uint8_t flags) -{ - sc->time_msg.data = hosttime; - - if (((flags & HV_ICTIMESYNCFLAG_SYNC) != 0) || - ((flags & HV_ICTIMESYNCFLAG_SAMPLE) != 0)) { - taskqueue_enqueue(taskqueue_thread, &sc->task); + if ((flags & HV_ICTIMESYNCFLAG_SAMPLE) != 0 && sample_drift != 0) { + if (bootverbose) { + device_printf(sc->ic_dev, "handle sample request " + "{host: %ju, guest: %ju}\n", + (uintmax_t)host_tns, (uintmax_t)guest_tns); + } + + diff = (int64_t)(host_tns - guest_tns) / HV_NANO_SEC_PER_MILLI_SEC; + if (diff > sample_drift || diff < -sample_drift) { + error = kern_clock_settime(curthread, CLOCK_REALTIME, + &host_ts); + if (bootverbose) + device_printf(sc->ic_dev, "trigger sample sync"); + } + return; } } @@ -145,12 +160,12 @@ hv_timesync_cb(struct vmbus_channel *cha int ret; uint8_t* time_buf; struct hv_ictimesync_data* timedatap; - hv_timesync_sc *softc; + hv_util_sc *softc; - softc = (hv_timesync_sc*)context; - time_buf = softc->util_sc.receive_buffer; + softc = (hv_util_sc*)context; + time_buf = softc->receive_buffer; - recvlen = softc->util_sc.ic_buflen; + recvlen = softc->ic_buflen; ret = vmbus_chan_recv(channel, time_buf, &recvlen, &requestId); KASSERT(ret != ENOBUFS, ("hvtimesync recvbuf is not large enough")); /* XXX check recvlen to make sure that it contains enough data */ @@ -162,7 +177,7 @@ hv_timesync_cb(struct vmbus_channel *cha if (icmsghdrp->icmsgtype == HV_ICMSGTYPE_NEGOTIATE) { int error; - error = vmbus_ic_negomsg(&softc->util_sc, time_buf, &recvlen); + error = vmbus_ic_negomsg(softc, time_buf, &recvlen); if (error) return; } else { @@ -190,18 +205,12 @@ hv_timesync_probe(device_t dev) static int hv_timesync_attach(device_t dev) { - hv_timesync_sc *softc = device_get_softc(dev); - - TASK_INIT(&softc->task, 1, hv_set_host_time, softc); return hv_util_attach(dev, hv_timesync_cb); } static int hv_timesync_detach(device_t dev) { - hv_timesync_sc *softc = device_get_softc(dev); - - taskqueue_drain(taskqueue_thread, &softc->task); return hv_util_detach(dev); } @@ -213,7 +222,7 @@ static device_method_t timesync_methods[ { 0, 0 } }; -static driver_t timesync_driver = { "hvtimesync", timesync_methods, sizeof(hv_timesync_sc)}; +static driver_t timesync_driver = { "hvtimesync", timesync_methods, sizeof(hv_util_sc)}; static devclass_t timesync_devclass;
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