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188f87f264
x86_64 is already using the node's cpu as maximum threads. Make that the
default for all archs setting DEFERRED_STRUCT_PAGE_INIT.
This returns to the behavior prior making the function arch-specific with
commit ecd0965069 ("mm: make deferred init's max threads
arch-specific").
Setting DEFERRED_STRUCT_PAGE_INIT and testing on a few arm64 platforms
shows faster deferred_init_memmap completions:
| | x13s | SA8775p-ride | Ampere R137-P31 | Ampere HR330 |
| | Metal, 32GB | VM, 36GB | VM, 58GB | Metal, 128GB |
| | 8cpus | 8cpus | 8cpus | 32cpus |
|---------|-------------|--------------|-----------------|--------------|
| threads | ms (%) | ms (%) | ms (%) | ms (%) |
|---------|-------------|--------------|-----------------|--------------|
| 1 | 108 (0%) | 72 (0%) | 224 (0%) | 324 (0%) |
| cpus | 24 (-77%) | 36 (-50%) | 40 (-82%) | 56 (-82%) |
Michael Ellerman reported:
: On a machine here (1TB, 40 cores, 4KB pages) the existing code gives:
:
: [ 0.500124] node 2 deferred pages initialised in 210ms
: [ 0.515790] node 3 deferred pages initialised in 230ms
: [ 0.516061] node 0 deferred pages initialised in 230ms
: [ 0.516522] node 7 deferred pages initialised in 230ms
: [ 0.516672] node 4 deferred pages initialised in 230ms
: [ 0.516798] node 6 deferred pages initialised in 230ms
: [ 0.517051] node 5 deferred pages initialised in 230ms
: [ 0.523887] node 1 deferred pages initialised in 240ms
:
: vs with the patch:
:
: [ 0.379613] node 0 deferred pages initialised in 90ms
: [ 0.380388] node 1 deferred pages initialised in 90ms
: [ 0.380540] node 4 deferred pages initialised in 100ms
: [ 0.390239] node 6 deferred pages initialised in 100ms
: [ 0.390249] node 2 deferred pages initialised in 100ms
: [ 0.390786] node 3 deferred pages initialised in 110ms
: [ 0.396721] node 5 deferred pages initialised in 110ms
: [ 0.397095] node 7 deferred pages initialised in 110ms
:
: Which is a nice speedup.
[echanude@redhat.com: v3]
Link: https://lkml.kernel.org/r/20240528185455.643227-4-echanude@redhat.com
Link: https://lkml.kernel.org/r/20240522203758.626932-4-echanude@redhat.com
Signed-off-by: Eric Chanudet <echanude@redhat.com>
Tested-by: Michael Ellerman <mpe@ellerman.id.au> (powerpc)
Reviewed-by: Baoquan He <bhe@redhat.com>
Acked-by: Alexander Gordeev <agordeev@linux.ibm.com>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov (AMD) <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Linux kernel
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