From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
To: Borislav Petkov <bp@alien8.de>,
Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>,
LKML <linux-kernel@vger.kernel.org>,
Linux PM <linux-pm@vger.kernel.org>,
Rafael Wysocki <rafael.j.wysocki@intel.com>,
"H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
X86 Kernel <x86@kernel.org>,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: [PATCH v2 2/2] powercap/rapl: reduce ipi calls
Date: Wed, 13 Jan 2016 13:54:43 -0800 [thread overview]
Message-ID: <1452722083.3092.92.camel@linux.intel.com> (raw)
In-Reply-To: <20160113212602.GT12897@pd.tnic>
On Wed, 2016-01-13 at 22:26 +0100, Borislav Petkov wrote:
[Cut]
>
> rmwmsrl_safe_on_cpu(policy->cpu, MSR_IA32_PERF_CTL,
> INTEL_PERF_CTL_MASK,
> (u32)sfi_cpufreq_array[next_perf_state].ctr
> l_val & INTEL_PERF_CTL_MASK);
>
> Yikes!
>
> So yes, it can work but it is ugly, hard to parse and use, not
> generic
> enough, etc, etc.
>
> So thanks, but no thanks.
>
I agree, in some cases it will not make much sense to use read-
modify_write calls, the user may decide whether it makes sense or not.
But such interface is not new to Linux kernel:
regmap_update_bits(), which is referenced for 346 times.
Are you saying that any such calls are not useful?
Thanks,
Srinivas
next prev parent reply other threads:[~2016-01-13 21:56 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-13 1:11 [PATCH v2 0/2] Reduce IPI calls for remote msr access Jacob Pan
2016-01-13 1:11 ` [PATCH v2 1/2] x86/msr: add on cpu read/modify/write function Jacob Pan
2016-01-13 1:11 ` [PATCH v2 2/2] powercap/rapl: reduce ipi calls Jacob Pan
2016-01-13 9:47 ` Thomas Gleixner
2016-01-13 16:21 ` Jacob Pan
2016-01-13 16:36 ` Borislav Petkov
2016-01-13 17:51 ` Jacob Pan
2016-01-13 18:04 ` Borislav Petkov
2016-01-13 18:21 ` Jacob Pan
2016-01-13 19:16 ` Borislav Petkov
2016-01-13 20:10 ` Jacob Pan
2016-01-13 21:26 ` Borislav Petkov
2016-01-13 21:54 ` Srinivas Pandruvada [this message]
2016-01-13 22:02 ` Thomas Gleixner
2016-01-13 22:11 ` Jacob Pan
2016-01-13 22:23 ` H. Peter Anvin
2016-01-13 22:16 ` Borislav Petkov
2016-01-13 22:39 ` Srinivas Pandruvada
2016-01-13 22:20 ` Jacob Pan
2016-01-13 22:29 ` Borislav Petkov
2016-01-13 21:49 ` Thomas Gleixner
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=1452722083.3092.92.camel@linux.intel.com \
--to=srinivas.pandruvada@linux.intel.com \
--cc=bp@alien8.de \
--cc=hpa@zytor.com \
--cc=jacob.jun.pan@linux.intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=mingo@redhat.com \
--cc=peterz@infradead.org \
--cc=rafael.j.wysocki@intel.com \
--cc=tglx@linutronix.de \
--cc=x86@kernel.org \
/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;
as well as URLs for NNTP newsgroup(s).