Nicholas Piggin 77f68ebeee powerpc/64s: enable MMU_LAZY_TLB_SHOOTDOWN
On a 16-socket 192-core POWER8 system, the context_switch1_threads
benchmark from will-it-scale (see earlier changelog), upstream can achieve
a rate of about 1 million context switches per second, due to contention
on the mm refcount.

64s meets the prerequisites for CONFIG_MMU_LAZY_TLB_SHOOTDOWN, so enable
the option.  This increases the above benchmark to 118 million context
switches per second.

This generates 314 additional IPI interrupts on a 144 CPU system doing a
kernel compile, which is in the noise in terms of kernel cycles.

Link: https://lkml.kernel.org/r/20230203071837.1136453-6-npiggin@gmail.com
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nadav Amit <nadav.amit@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2023-03-28 16:20:08 -07:00
2022-09-28 09:02:20 +02:00
2023-03-26 14:40:20 -07:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.
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