starlingx/integ
Code Issues Proposed changes
f3a6361ce3
integ/base/systemd/centos/patches/916-sd-event-don-t-provide-priority-stability.patch
Li Zhou ccfeeef59d systemd: Prevent excessive /proc/1/mountinfo reparsing 
Backport the patches for this issue:
https://bugzilla.redhat.com/show_bug.cgi?id=1819868

We met such an issue:
When testing a large number of pods (> 230), occasionally observed a
number of issues related to systemd process:
    systemd ran continually 90-100% cpu usage
    systemd memory usage started increasing rapidly (20GB/hour)
    systemctl commands would always timeout (Failed to get properties:
        Connection timed out)
    sm services failed and can't recover: open-ldap,
        registry-token-server, docker-distribution, etcd
    new pods can't start, and got stuck in state ContainerCreating

Those patches work to prevent excessive /proc/1/mountinfo reparsing.
It has been verified that those patches can improve this performance
greatly.

16 commits are listed in sequence (from [1] to [16]) at below link
for the issue:
https://github.com/systemd-rhel/rhel-8/pull/154/commits

[16](10)core: prevent excessive /proc/self/mountinfo parsing
[15][Dropped-6]test: add ratelimiting test
[14](9)sd-event: add ability to ratelimit event sources
[13](8)sd-event: increase n_enabled_child_sources just once
[12](7)sd-event: update state at the end in event_source_enable
[11](6)sd-event: remove earliest_index/latest_index into common part of
event source objects
[10][Dropped-5]sd-event: follow coding style with naming return
parameter
[9] [Dropped-4]sd-event: ref event loop while in sd_event_prepare() ot
sd_event_run()
[8] (5)sd-event: refuse running default event loops in any other thread
than the one they are default for
[7] [Dropped-3]sd-event: let's suffix last_run/last_log with "_usec"
[6] [Dropped-2]sd-event: fix delays assert brain-o (#17790)
[5] (4)sd-event: split out code to add/remove timer event sources to
earliest/latest prioq
[4] (3)sd-event: split clock data allocation out of sd_event_add_time()
[3] [Dropped-1]sd-event: mention that two debug logged events are
ignored
[2] (2)sd-event: split out enable and disable codepaths from
sd_event_source_set_enabled()
[1] (1)sd-event: split out helper functions for reshuffling prioqs

I ported 10 of them back (from (1) to (10)) to fix this issue
and dropped the other 6 (from [Dropped-1] to [Dropped-6]) for those
reasons:
[Dropped-1]Only changes error log.
[Dropped-2]Fixes a bug introduced in a commit which doesn't exist in
this version.
[Dropped-3]Only changes vars' names and there is no functional change.
[Dropped-4]More commits are needed for merging it, while I don't see
any help on adding the rate-limiting ability.
[Dropped-5]Change coding style for a function which isn't really used
by anyone.
[Dropped-6]Add test cases.

Closes-Bug: #1924686
Signed-off-by: Li Zhou <li.zhou@windriver.com>
Change-Id: Ia4c8f162cb1a47b40d1b26cf4d604976b97e92d6
2021-04-22 22:09:33 -04:00

98 lines
2.9 KiB
Diff
Raw Blame History

From 2d07173304abd3f1d3fae5e0f01bf5874b1f04db Mon Sep 17 00:00:00 2001
From: David Herrmann <dh.herrmann@gmail.com>
Date: Tue, 29 Sep 2015 20:56:17 +0200
Subject: [PATCH 16/20] sd-event: don't provide priority stability
Currently, we guarantee that if two event-sources with the same priority
fire at the same time, they're always dispatched in the same order. While
this might sound nice in theory, there's is little benefit in providing
stability on that level. We have no control over the order the events are
reported, hence, we cannot guarantee that we get notified about both at
the same time.
By dropping the stability guarantee, we loose roughly 10% Heap swaps in
the prioq on a desktop cold-boot. Krzysztof Kotlenga even reported up to
20% on his tests. This sounds worth optimizing, so drop the stability
guarantee.
[commit 6fe869c251790a0e3cef5b243169dda363723f49 from
https://github.com/systemd-rhel/rhel-8/]
Signed-off-by: Li Zhou <li.zhou@windriver.com>
---
src/libsystemd/sd-event/sd-event.c | 30 ------------------------------
1 file changed, 30 deletions(-)
diff --git a/src/libsystemd/sd-event/sd-event.c b/src/libsystemd/sd-event/sd-event.c
index e34fd0b..6304991 100644
--- a/src/libsystemd/sd-event/sd-event.c
+++ b/src/libsystemd/sd-event/sd-event.c
@@ -243,12 +243,6 @@ static int pending_prioq_compare(const void *a, const void *b) {
if (x->pending_iteration > y->pending_iteration)
return 1;
- /* Stability for the rest */
- if (x < y)
- return -1;
- if (x > y)
- return 1;
-
return 0;
}
@@ -278,12 +272,6 @@ static int prepare_prioq_compare(const void *a, const void *b) {
if (x->priority > y->priority)
return 1;
- /* Stability for the rest */
- if (x < y)
- return -1;
- if (x > y)
- return 1;
-
return 0;
}
@@ -311,12 +299,6 @@ static int earliest_time_prioq_compare(const void *a, const void *b) {
if (x->time.next > y->time.next)
return 1;
- /* Stability for the rest */
- if (x < y)
- return -1;
- if (x > y)
- return 1;
-
return 0;
}
@@ -344,12 +326,6 @@ static int latest_time_prioq_compare(const void *a, const void *b) {
if (x->time.next + x->time.accuracy > y->time.next + y->time.accuracy)
return 1;
- /* Stability for the rest */
- if (x < y)
- return -1;
- if (x > y)
- return 1;
-
return 0;
}
@@ -371,12 +347,6 @@ static int exit_prioq_compare(const void *a, const void *b) {
if (x->priority > y->priority)
return 1;
- /* Stability for the rest */
- if (x < y)
- return -1;
- if (x > y)
- return 1;
-
return 0;
}
--
2.17.1
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