From: David Laight <David.Laight@ACULAB.COM>
To: 'Guo Ren' <guoren@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>,
Evgenii Shatokhin <e.shatokhin@yadro.com>,
"suagrfillet@gmail.com" <suagrfillet@gmail.com>,
"andy.chiu@sifive.com" <andy.chiu@sifive.com>,
"linux-riscv@lists.infradead.org"
<linux-riscv@lists.infradead.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Guo Ren <guoren@linux.alibaba.com>,
"anup@brainfault.org" <anup@brainfault.org>,
"paul.walmsley@sifive.com" <paul.walmsley@sifive.com>,
"palmer@dabbelt.com" <palmer@dabbelt.com>,
"conor.dooley@microchip.com" <conor.dooley@microchip.com>,
"heiko@sntech.de" <heiko@sntech.de>,
"rostedt@goodmis.org" <rostedt@goodmis.org>,
"mhiramat@kernel.org" <mhiramat@kernel.org>,
"jolsa@redhat.com" <jolsa@redhat.com>, "bp@suse.de" <bp@suse.de>,
"jpoimboe@kernel.org" <jpoimboe@kernel.org>,
"linux@yadro.com" <linux@yadro.com>
Subject: RE: [PATCH -next V7 0/7] riscv: Optimize function trace
Date: Thu, 9 Feb 2023 09:00:13 +0000 [thread overview]
Message-ID: <f00256bcbe114669acca1b0105cefb99@AcuMS.aculab.com> (raw)
In-Reply-To: <CAJF2gTQGxxgusRgPdNaw4-d+o0a4vefUj7PNpZuym6VKQC4dhw@mail.gmail.com>
From: Guo Ren
> Sent: 09 February 2023 01:51
...
> Yours cost one more instruction, right?
> addr-12 auipc
> addr-8 jalr
> addr-4 // Literal (32-bits)
> addr+0 nop or jmp addr-n // one more?
> addr+4 function_code
Yes, it is 4 bytes larger but there is one less
instruction executed (only one nop) when ftrace is disabled.
That probably matters more than anything in the ftrace
'prologue' code.
I also suspect that you can use a 32bit integer as
a table index in 64bit mode to save a word there.
David
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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)
next prev parent reply other threads:[~2023-02-09 9:00 UTC|newest]
Thread overview: 44+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-12 9:05 [PATCH -next V7 0/7] riscv: Optimize function trace guoren
2023-01-12 9:05 ` [PATCH -next V7 1/7] riscv: ftrace: Fixup panic by disabling preemption guoren
2023-01-12 12:16 ` Mark Rutland
2023-01-12 12:57 ` Mark Rutland
2023-01-28 9:45 ` Guo Ren
2023-01-28 9:37 ` Guo Ren
2023-01-30 10:54 ` Mark Rutland
2023-02-04 1:19 ` Guo Ren
2023-01-12 9:05 ` [PATCH -next V7 2/7] riscv: ftrace: Remove wasted nops for !RISCV_ISA_C guoren
2023-01-12 9:05 ` [PATCH -next V7 3/7] riscv: ftrace: Reduce the detour code size to half guoren
2023-01-16 14:11 ` Evgenii Shatokhin
2023-01-12 9:06 ` [PATCH -next V7 4/7] riscv: ftrace: Add ftrace_graph_func guoren
2023-01-12 9:06 ` [PATCH -next V7 5/7] riscv: ftrace: Add DYNAMIC_FTRACE_WITH_DIRECT_CALLS support guoren
2023-01-12 9:06 ` [PATCH -next V7 6/7] samples: ftrace: Add riscv support for SAMPLE_FTRACE_DIRECT[_MULTI] guoren
2023-01-16 14:30 ` Evgenii Shatokhin
2023-01-17 9:32 ` Song Shuai
2023-01-17 13:16 ` Evgenii Shatokhin
2023-01-17 16:22 ` Evgenii Shatokhin
2023-01-18 2:37 ` Song Shuai
2023-01-18 15:19 ` Evgenii Shatokhin
2023-01-19 6:05 ` Guo Ren
2023-02-18 21:30 ` Palmer Dabbelt
2023-02-20 2:46 ` Song Shuai
2023-02-21 3:56 ` Guo Ren
2023-02-21 4:02 ` Guo Ren
2023-01-12 9:06 ` [PATCH -next V7 7/7] riscv : select FTRACE_MCOUNT_USE_PATCHABLE_FUNCTION_ENTRY guoren
2023-01-16 15:02 ` [PATCH -next V7 0/7] riscv: Optimize function trace Evgenii Shatokhin
2023-02-04 6:40 ` Guo Ren
2023-02-06 9:56 ` Mark Rutland
2023-02-07 3:57 ` Guo Ren
2023-02-07 9:16 ` Mark Rutland
2023-02-08 2:30 ` Guo Ren
2023-02-08 14:46 ` Mark Rutland
2023-02-09 1:31 ` Guo Ren
2023-02-09 22:46 ` David Laight
2023-02-10 2:18 ` Guo Ren
2023-02-08 22:29 ` David Laight
2023-02-09 1:51 ` Guo Ren
2023-02-09 1:59 ` Guo Ren
2023-02-09 9:54 ` Mark Rutland
2023-02-10 2:21 ` Guo Ren
2023-02-09 9:00 ` David Laight [this message]
2023-02-09 9:11 ` Guo Ren
2023-02-18 21:42 ` patchwork-bot+linux-riscv
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