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From: Peter Zijlstra <peterz@infradead.org>
To: linux-kernel@vger.kernel.org, x86@kernel.org
Cc: Nadav Amit <nadav.amit@gmail.com>,
	Andy Lutomirski <luto@kernel.org>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Song Liu <songliubraving@fb.com>,
	Daniel Bristot de Oliveira <bristot@redhat.com>,
	Steven Rostedt <rostedt@goodmis.org>
Subject: Re: [PATCH 2/3] x86/alternatives: Move tp_vec
Date: Mon, 26 Aug 2019 16:36:47 +0200	[thread overview]
Message-ID: <20190826143647.GV2369@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <20190826125519.798115791@infradead.org>

On Mon, Aug 26, 2019 at 02:51:40PM +0200, Peter Zijlstra wrote:

> +#define TP_VEC_MAX (PAGE_SIZE / sizeof(struct text_poke_loc))
> +extern struct text_poke_loc tp_vec[TP_VEC_MAX];
> +extern int tp_vec_nr;

FWIW, that currently results in a batch size of 128, but I've not
noticed any delay in flipping ftrace on and off on the commandline.

Growing that buffer really shouldn't be a problem, but I'm thinking we'd
want solid performance numbers to justify it.

  reply	other threads:[~2019-08-26 14:37 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-08-26 12:51 [PATCH 0/3] Rewrite x86/ftrace to use text_poke() Peter Zijlstra
2019-08-26 12:51 ` [PATCH 1/3] x86/alternatives: Teach text_poke_bp() to emulate instructions Peter Zijlstra
2019-08-26 12:51 ` [PATCH 2/3] x86/alternatives: Move tp_vec Peter Zijlstra
2019-08-26 14:36   ` Peter Zijlstra [this message]
2019-08-26 12:51 ` [RFC][PATCH 3/3] x86/ftrace: Use text_poke() Peter Zijlstra
2019-08-26 15:13   ` Peter Zijlstra
2019-08-26 13:04 ` [PATCH 0/3] Rewrite x86/ftrace to use text_poke() Peter Zijlstra

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