From: Andi Kleen <andi@firstfloor.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Andi Kleen <andi@firstfloor.org>,
akpm@linux-foundation.org, linux-kernel@vger.kernel.org,
viro@zeniv.linux.org.uk
Subject: Re: [PATCH] proc: faster /proc/*/status
Date: Sun, 7 Aug 2016 09:59:47 -0700 [thread overview]
Message-ID: <20160807165947.GX5871@two.firstfloor.org> (raw)
In-Reply-To: <20160807085322.GB1871@p183.telecom.by>
> And then what? Parsing format string is still be there.
Perhaps could have a fast path for simple cases.
>
> This is first line of profile of the first function (format_decode)
>
> │ static noinline_for_stack
> │ int format_decode(const char *fmt, struct printf_spec *spec)
> │ {
> 10.38 │ push %rbp <===
> 1.07 │ mov %rsp,%rbp
> 1.09 │ push %r12
> 4.51 │ mov %rsi,%r12
> 1.40 │ push %rbx
> 1.86 │ mov %rdi,%rbx
> │ sub $0x8,%rsp
>
> It is so bloated that gcc needs to be asked to not screw up with stack
> size.
What happens when you drop all the noinlines for this? I assume
this would alread make it faster. And now that we have bigger
stacks we can likely tolerate it.
-Andi
--
ak@linux.intel.com -- Speaking for myself only.
next prev parent reply other threads:[~2016-08-07 16:59 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-08-06 12:56 [PATCH] proc: faster /proc/*/status Alexey Dobriyan
2016-08-06 22:41 ` Joe Perches
2016-08-09 3:02 ` [PATCH] seq/proc: Modify seq_put_decimal_[u]ll to take a const char *, not char Joe Perches
2016-08-07 3:16 ` [PATCH] proc: faster /proc/*/status Andi Kleen
2016-08-07 8:53 ` Alexey Dobriyan
2016-08-07 16:59 ` Andi Kleen [this message]
2016-08-07 17:39 ` Joe Perches
2016-08-07 17:44 ` Andi Kleen
2016-08-07 21:22 ` Joe Perches
2016-08-09 23:25 ` Andrew Morton
2016-08-10 6:38 ` [RFC PATCH] meminfo: Break apart a very long seq_printf with #ifdefs Joe Perches
2016-08-11 21:50 ` Andrew Morton
2016-08-11 21:57 ` Joe Perches
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