From: Benjamin Gray <bgray@linux.ibm.com>
To: Christophe Leroy <christophe.leroy@csgroup.eu>,
Ard Biesheuvel <ardb@kernel.org>
Cc: X86 ML <x86@kernel.org>, Peter Zijlstra <peterz@infradead.org>,
"open list:LINUX FOR POWERPC \(32-BIT AND 64-BIT\)"
<linuxppc-dev@lists.ozlabs.org>,
Dave Hansen <dave.hansen@linux.intel.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Nicholas Piggin <npiggin@gmail.com>,
Jason Baron <jbaron@akamai.com>, Ingo Molnar <mingo@redhat.com>,
"sv@linux.ibm.com" <sv@linux.ibm.com>,
"Steven Rostedt \(VMware\)" <rostedt@goodmis.org>,
"H. Peter Anvin" <hpa@zytor.com>, Borislav Petkov <bp@alien8.de>,
Thomas Gleixner <tglx@linutronix.de>,
"agust@denx.de" <agust@denx.de>,
Chen Zhongjin <chenzhongjin@huawei.com>,
Josh Poimboeuf <jpoimboe@kernel.org>
Subject: Re: [PATCH v2 0/7] Implement inline static calls on PPC32 - v2
Date: Thu, 08 Sep 2022 10:13:57 +1000 [thread overview]
Message-ID: <47772b9ae10be6dbe5b0cfcd0bc14efc8fb22c0c.camel@linux.ibm.com> (raw)
In-Reply-To: <d35a2039-1755-b0be-6733-bb7ec19b2ea8@csgroup.eu>
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On Thu, 2022-09-01 at 16:46 +0000, Christophe Leroy wrote:
> Surprisingly, I get worst performance with inline static call than
> with
> out of line static call:
I'm not sure what hackbench is doing, but when microbenchmarking 64 bit
out-of-line calls in a loop I saw a similar thing where adding more
indirection improved the performance despite doing more work. The cause
seemed to be a combination of using older hardware and the target being
too short (just an integer increment). Moving to a newer machine and
adding a lot of NOPs to the target made the performance make sense.
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next prev parent reply other threads:[~2022-09-08 0:16 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-07-08 17:31 [PATCH v2 0/7] Implement inline static calls on PPC32 - v2 Christophe Leroy
2022-07-08 17:31 ` [PATCH v2 1/7] powerpc: Add missing asm/asm.h for objtool Christophe Leroy
2022-07-08 17:31 ` [PATCH v2 2/7] objtool/powerpc: Activate objtool on PPC32 Christophe Leroy
2022-07-08 17:31 ` [PATCH v2 3/7] objtool: Add architecture specific R_REL32 macro Christophe Leroy
2022-07-08 17:31 ` [PATCH v2 4/7] objtool/powerpc: Add necessary support for inline static calls Christophe Leroy
2022-07-08 17:31 ` [PATCH v2 5/7] init: Call static_call_init() from start_kernel() Christophe Leroy
2022-07-08 17:31 ` [PATCH v2 6/7] static_call_inline: Provide trampoline address when updating sites Christophe Leroy
2022-07-08 17:31 ` [PATCH v2 7/7] powerpc/static_call: Implement inline static calls Christophe Leroy
2022-07-09 6:52 ` [PATCH v2 0/7] Implement inline static calls on PPC32 - v2 Ard Biesheuvel
2022-09-01 16:46 ` Christophe Leroy
2022-09-08 0:13 ` Benjamin Gray [this message]
2022-09-08 6:11 ` Christophe Leroy
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