From: Davidlohr Bueso <dave@stgolabs.net>
To: Yunhui Cui <cuiyunhui@bytedance.com>
Cc: pjw@kernel.org, palmer@dabbelt.com, aou@eecs.berkeley.edu,
alex@ghiti.fr, dennis@kernel.org, tj@kernel.org, cl@gentwo.org,
ast@kernel.org, daniel@iogearbox.net, andrii@kernel.org,
martin.lau@linux.dev, eddyz87@gmail.com, memxor@gmail.com,
song@kernel.org, yonghong.song@linux.dev, jolsa@kernel.org,
bjorn@kernel.org, pulehui@huawei.com, puranjay@kernel.org,
thuth@redhat.com, ajones@ventanamicro.com,
ben.dooks@codethink.co.uk, rkrcmar@ventanamicro.com,
samuel.holland@sifive.com, zong.li@sifive.com,
conor.dooley@microchip.com, tglx@kernel.org, debug@rivosinc.com,
seanwascoding@gmail.com, andybnac@gmail.com,
menglong8.dong@gmail.com, cyrilbur@tenstorrent.com,
wangruikang@iscas.ac.cn, atishp@rivosinc.com,
apatel@ventanamicro.com, linux-riscv@lists.infradead.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org,
bpf@vger.kernel.org, arnd@arndb.de, nathan@kernel.org,
nick.desaulniers+lkml@gmail.com, morbo@google.com,
justinstitt@google.com, qingfang.deng@siflower.com.cn,
linux-arch@vger.kernel.org, llvm@lists.linux.dev
Subject: Re: [PATCH v8 3/3] riscv: store percpu offset into thread_info
Date: Tue, 25 Aug 2026 18:24:57 -0700 [thread overview]
Message-ID: <20260826012457.ig3rfmji7vywf6kc@offworld> (raw)
In-Reply-To: <20260703122832.15984-4-cuiyunhui@bytedance.com>
On Fri, 03 Jul 2026, Yunhui Cui wrote:
>RISC-V percpu addressing currently derives the base offset from the CPU
>number and __per_cpu_offset[]. Cache the current CPU percpu offset in
>thread_info so percpu accesses can load it directly.
fyi on a sifive p550 I am seeing this_cpu_inc() cost dropping by ~15-20%
an adhoc microbench measuring/grouping various calls.
Thanks,
Davidlohr
prev parent reply other threads:[~2026-08-26 1:34 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-03 12:28 [PATCH v8 0/3] riscv: fix PIO helpers and add optimized percpu ops Yunhui Cui
2026-07-03 12:28 ` [PATCH v8 1/3] riscv: io: avoid null-pointer arithmetic in PIO helpers Yunhui Cui
2026-07-13 18:03 ` Paul Walmsley
2026-07-14 6:23 ` [External] " yunhui cui
2026-07-03 12:28 ` [PATCH v8 2/3] riscv: introduce percpu.h into include/asm Yunhui Cui
2026-08-26 1:07 ` Davidlohr Bueso
2026-07-03 12:28 ` [PATCH v8 3/3] riscv: store percpu offset into thread_info Yunhui Cui
2026-07-03 21:02 ` Thomas Gleixner
2026-08-26 1:24 ` Davidlohr Bueso [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20260826012457.ig3rfmji7vywf6kc@offworld \
--to=dave@stgolabs.net \
--cc=ajones@ventanamicro.com \
--cc=alex@ghiti.fr \
--cc=andrii@kernel.org \
--cc=andybnac@gmail.com \
--cc=aou@eecs.berkeley.edu \
--cc=apatel@ventanamicro.com \
--cc=arnd@arndb.de \
--cc=ast@kernel.org \
--cc=atishp@rivosinc.com \
--cc=ben.dooks@codethink.co.uk \
--cc=bjorn@kernel.org \
--cc=bpf@vger.kernel.org \
--cc=cl@gentwo.org \
--cc=conor.dooley@microchip.com \
--cc=cuiyunhui@bytedance.com \
--cc=cyrilbur@tenstorrent.com \
--cc=daniel@iogearbox.net \
--cc=debug@rivosinc.com \
--cc=dennis@kernel.org \
--cc=eddyz87@gmail.com \
--cc=jolsa@kernel.org \
--cc=justinstitt@google.com \
--cc=linux-arch@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=linux-riscv@lists.infradead.org \
--cc=llvm@lists.linux.dev \
--cc=martin.lau@linux.dev \
--cc=memxor@gmail.com \
--cc=menglong8.dong@gmail.com \
--cc=morbo@google.com \
--cc=nathan@kernel.org \
--cc=nick.desaulniers+lkml@gmail.com \
--cc=palmer@dabbelt.com \
--cc=pjw@kernel.org \
--cc=pulehui@huawei.com \
--cc=puranjay@kernel.org \
--cc=qingfang.deng@siflower.com.cn \
--cc=rkrcmar@ventanamicro.com \
--cc=samuel.holland@sifive.com \
--cc=seanwascoding@gmail.com \
--cc=song@kernel.org \
--cc=tglx@kernel.org \
--cc=thuth@redhat.com \
--cc=tj@kernel.org \
--cc=wangruikang@iscas.ac.cn \
--cc=yonghong.song@linux.dev \
--cc=zong.li@sifive.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox