git: 70201cc45dc7 - stable/13 - Reduce minimum idle hardclock rate from 2Hz to 1Hz.

[Alexander Motin]

The branch stable/13 has been updated by mav:

URL: 
https://cgit.FreeBSD.org/src/commit/?id=70201cc45dc7c3466a852e6b93e02dfd13fc8f59

commit 70201cc45dc7c3466a852e6b93e02dfd13fc8f59
Author:     Alexander Motin <m...@freebsd.org>
AuthorDate: 2022-01-10 00:17:43 +0000
Commit:     Alexander Motin <m...@freebsd.org>
CommitDate: 2022-01-24 02:35:58 +0000

    Reduce minimum idle hardclock rate from 2Hz to 1Hz.
    
    On idle 80-thread system it allows to improve package-level idle state
    residency and so power consumption by several percent.
    
    MFC after:      2 weeks
    
    (cherry picked from commit cb1f5d11366dc9b803f2755d83fe02599830882a)
---
 sys/kern/kern_clocksource.c | 5 +++--
 sys/kern/kern_timeout.c     | 5 ++---
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/sys/kern/kern_clocksource.c b/sys/kern/kern_clocksource.c
index dfc9081ba9f6..48e06ee082fc 100644
--- a/sys/kern/kern_clocksource.c
+++ b/sys/kern/kern_clocksource.c
@@ -239,13 +239,14 @@ getnextcpuevent(int idle)
        /* Handle hardclock() events, skipping some if CPU is idle. */
        event = state->nexthard;
        if (idle) {
-               hardfreq = (u_int)hz / 2;
-               if (tc_min_ticktock_freq > 2
+               if (tc_min_ticktock_freq > 1
 #ifdef SMP
                    && curcpu == CPU_FIRST()
 #endif
                    )
                        hardfreq = hz / tc_min_ticktock_freq;
+               else
+                       hardfreq = hz;
                if (hardfreq > 1)
                        event += tick_sbt * (hardfreq - 1);
        }
diff --git a/sys/kern/kern_timeout.c b/sys/kern/kern_timeout.c
index 992a093d30ab..2e98c1033ee3 100644
--- a/sys/kern/kern_timeout.c
+++ b/sys/kern/kern_timeout.c
@@ -418,8 +418,7 @@ callout_process(sbintime_t now)
        struct callout *tmp, *tmpn;
        struct callout_cpu *cc;
        struct callout_list *sc;
-       sbintime_t first, last, max, tmp_max;
-       uint32_t lookahead;
+       sbintime_t first, last, lookahead, max, tmp_max;
        u_int firstb, lastb, nowb;
 #ifdef CALLOUT_PROFILING
        int depth_dir = 0, mpcalls_dir = 0, lockcalls_dir = 0;
@@ -439,7 +438,7 @@ callout_process(sbintime_t now)
        else if (nowb - firstb == 1)
                lookahead = (SBT_1S / 8);
        else
-               lookahead = (SBT_1S / 2);
+               lookahead = SBT_1S;
        first = last = now;
        first += (lookahead / 2);
        last += lookahead;