76 lines
2.7 KiB
Diff
76 lines
2.7 KiB
Diff
From 52444dc478fe38b5b69a771923ab429a41927aa5 Mon Sep 17 00:00:00 2001
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From: Lennart Poettering <lennart@poettering.net>
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Date: Mon, 24 Mar 2014 23:54:21 +0100
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Subject: [PATCH] sd-event: initialization perturbation value right before we
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use it
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That way, we don't forget to initialize it when the watchdog is
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initialized before all event sources.
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---
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src/libsystemd/sd-event/sd-event.c | 34 +++++++++++++++++++++-------------
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1 file changed, 21 insertions(+), 13 deletions(-)
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--- src/libsystemd/sd-event/sd-event.c
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+++ src/libsystemd/sd-event/sd-event.c 2014-03-28 12:44:05.652327044 +0000
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@@ -648,13 +648,31 @@ _public_ int sd_event_add_io(
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return 0;
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}
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+static void initialize_perturb(sd_event *e) {
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+ sd_id128_t bootid = {};
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+
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+ /* When we sleep for longer, we try to realign the wakeup to
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+ the same time wihtin each minute/second/250ms, so that
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+ events all across the system can be coalesced into a single
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+ CPU wakeup. However, let's take some system-specific
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+ randomness for this value, so that in a network of systems
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+ with synced clocks timer events are distributed a
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+ bit. Here, we calculate a perturbation usec offset from the
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+ boot ID. */
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+
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+ if (_likely_(e->perturb != (usec_t) -1))
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+ return;
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+
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+ if (sd_id128_get_boot(&bootid) >= 0)
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+ e->perturb = (bootid.qwords[0] ^ bootid.qwords[1]) % USEC_PER_MINUTE;
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+}
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+
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static int event_setup_timer_fd(
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sd_event *e,
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EventSourceType type,
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int *timer_fd,
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clockid_t id) {
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- sd_id128_t bootid = {};
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struct epoll_event ev = {};
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int r, fd;
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@@ -677,18 +695,6 @@ static int event_setup_timer_fd(
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return -errno;
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}
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- /* When we sleep for longer, we try to realign the wakeup to
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- the same time wihtin each minute/second/250ms, so that
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- events all across the system can be coalesced into a single
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- CPU wakeup. However, let's take some system-specific
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- randomness for this value, so that in a network of systems
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- with synced clocks timer events are distributed a
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- bit. Here, we calculate a perturbation usec offset from the
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- boot ID. */
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-
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- if (sd_id128_get_boot(&bootid) >= 0)
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- e->perturb = (bootid.qwords[0] ^ bootid.qwords[1]) % USEC_PER_MINUTE;
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-
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*timer_fd = fd;
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return 0;
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}
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@@ -1506,6 +1512,8 @@ static usec_t sleep_between(sd_event *e,
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if (b <= a + 1)
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return a;
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+ initialize_perturb(e);
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+
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/*
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Find a good time to wake up again between times a and b. We
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have two goals here:
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