15.02.2026 23:49, Klemens Nanni пишет:
> 30.12.2025 22:18, Mark Kettenis пишет:
>>> Date: Tue, 30 Dec 2025 19:05:03 +0100
>>> From: Alexander Bluhm <[email protected]>
>>>
>>> On Sun, Nov 23, 2025 at 04:14:31PM +0000, Miod Vallat wrote:
>>>>> All cores attached, i.e. octeon's hw_cpu_hatch() should've run
>>>>> and bumped `ncpus' four times.
>>>>
>>>> Except that this only happens after cpu_boot_secondary_processors()
>>>> completes, which is way later than softnet_percpu().
>>>
>>> octeon sets ncpus late, but ncpusfound is set early. Other subsystems
>>> also use that variable. My mistake using the wrong one.
>>
>> No, you used the right one.
>>
>> * ncpusfound: the number of CPUs the hardware provides
>>
>> * ncpus: the number of CPUs OpenBSD is using
>>
>> So when running a GENERIC kernel on a machine with 32 CPUs, ncpusfound
>> will be 32 but ncpus will be 1.
>>
>> Even when running a GENERIC.MP kernel, ncpusfound may be larger than
>> ncpus. This could happen if the hardware has more than MAXCPUS CPUs.
>>
>> We probably should change octeon to bump ncpus when it attaches CPUs
>> instead of when it spins them up.
>
> I gave it a quick try today:
>
> root@ot8:.../~# ps xk |grep softnet
> 68767 ?? DK 0:00.00 (softnet3)
> 71399 ?? DK 0:00.00 (softnet4)
> 75753 ?? DK 0:00.00 (softnet5)
> 95091 ?? DK 0:00.00 (softnet6)
> 69574 ?? DK 0:00.00 (softnet7)
> 31463 ?? DK 0:00.00 (softnet0)
> 26770 ?? DK 0:00.00 (softnet2)
> 37751 ?? DK 0:00.00 (softnet1)
> 23114 00 S+p 0:00.01 grep softnet
>
> root@ot8:.../~# sysctl hw | grep cpu
> hw.ncpu=17
> hw.cpuspeed=1800
> hw.ncpufound=16
> hw.ncpuonline=16
>
> Obvious off-by-one still, but incrementing on attach works.
Needed to hoist the increment from below this check into the else:
#ifdef MULTIPROCESSOR
if (cpuno == 0) {
...
} else {
...
}
#else
>
> If that's the right direction, I'll fix up the diff next week.
Now it logically matches what arm64, macppc and powerpc64 (and probably
others archs) so:
root@ot8:.../~# sysctl hw | grep cpu
hw.ncpu=16
hw.cpuspeed=1800
hw.ncpufound=16
Test machine and router are happy with the final diff below.
I have not done any performance measurements wrt. +7 softnet threads,
but this strikes me as correctness fix on its own.
Also, octeon get_ncpusfound()'s local variable shadowing the global in
kern/init_main.c is not helpful in that it at least produces grep noise,
so I renamed that.
Feedback? Objection? OK?
Index: mips64/mips64/cpu.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/arch/mips64/mips64/cpu.c,v
diff -u -p -r1.85 cpu.c
--- mips64/mips64/cpu.c 5 Jun 2025 09:29:54 -0000 1.85
+++ mips64/mips64/cpu.c 21 Feb 2026 20:48:26 -0000
@@ -99,6 +99,7 @@ cpuattach(struct device *parent, struct
ci->ci_next = cpu_info_list->ci_next;
cpu_info_list->ci_next = ci;
ci->ci_flags |= CPUF_PRESENT;
+ ncpus++;
}
#else
ci = &cpu_info_primary;
Index: octeon/octeon/machdep.c
===================================================================
RCS file: /mount/openbsd/cvs/src/sys/arch/octeon/octeon/machdep.c,v
diff -u -p -r1.137 machdep.c
--- octeon/octeon/machdep.c 24 Oct 2023 13:20:10 -0000 1.137
+++ octeon/octeon/machdep.c 21 Feb 2026 20:49:01 -0000
@@ -802,7 +802,7 @@ static u_int64_t
get_ncpusfound(void)
{
uint64_t core_mask;
- uint64_t i, ncpus = 0;
+ uint64_t i, n = 0;
int chipid;
chipid = octeon_get_chipid();
@@ -818,9 +818,9 @@ get_ncpusfound(void)
/* There has to be 1-to-1 mapping between cpuids and coreids. */
for (i = 0; i < OCTEON_MAXCPUS && (core_mask & (1ul << i)) != 0; i++)
- ncpus++;
+ n++;
- return ncpus;
+ return n;
}
static enum octeon_board
@@ -1333,8 +1333,6 @@ hw_cpu_hatch(struct cpu_info *ci)
ci->ci_flags |= CPUF_RUNNING;
membar_sync();
-
- ncpus++;
spl0();
(void)updateimask(0);
