From: Dave Hansen <dave@sr71.net>
To: Davidlohr Bueso <davidlohr@hp.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
ak@linux.intel.com, kirill.shutemov@linux.intel.com,
mgorman@suse.de, alex.shi@linaro.org, x86@kernel.org,
linux-mm@kvack.org, dave.hansen@linux.intel.com
Subject: Re: [PATCH 5/7] x86: mm: new tunable for single vs full TLB flush
Date: Fri, 07 Mar 2014 09:19:09 -0800 [thread overview]
Message-ID: <5319FF8D.1080107@sr71.net> (raw)
In-Reply-To: <1394156230.2555.19.camel@buesod1.americas.hpqcorp.net>
On 03/06/2014 05:37 PM, Davidlohr Bueso wrote:
> On Wed, 2014-03-05 at 16:45 -0800, Dave Hansen wrote:
>> From: Dave Hansen <dave.hansen@linux.intel.com>
>> +
>> +If you believe that invlpg is being called too often, you can
>> +lower the tunable:
>> +
>> + /sys/debug/kernel/x86/tlb_single_page_flush_ceiling
>> +
>
> Whenever this tunable needs to be updated, most users will not know what
> a invlpg is and won't think in terms of pages either. How about making
> this in units of Kb instead? But then again most of those users won't be
> looking into tlb flushing issues anyways, so...
Yeah, talking about the instruction directly in the documentation is
probably going a bit far. I'll see if I can uplevel it a bit.
It's obviously not a big deal to change it to be pages vs. kb, but for
something that's as *COMPLETELY* developer-focused, I think we can keep
it in pages. We don't want users fooling with this.
> While obvious, tt should also mention that this does not apply to
> hugepages.
Good point.
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WARNING: multiple messages have this Message-ID (diff)
From: Dave Hansen <dave@sr71.net>
To: Davidlohr Bueso <davidlohr@hp.com>
Cc: linux-kernel@vger.kernel.org, akpm@linux-foundation.org,
ak@linux.intel.com, kirill.shutemov@linux.intel.com,
mgorman@suse.de, alex.shi@linaro.org, x86@kernel.org,
linux-mm@kvack.org, dave.hansen@linux.intel.com
Subject: Re: [PATCH 5/7] x86: mm: new tunable for single vs full TLB flush
Date: Fri, 07 Mar 2014 09:19:09 -0800 [thread overview]
Message-ID: <5319FF8D.1080107@sr71.net> (raw)
In-Reply-To: <1394156230.2555.19.camel@buesod1.americas.hpqcorp.net>
On 03/06/2014 05:37 PM, Davidlohr Bueso wrote:
> On Wed, 2014-03-05 at 16:45 -0800, Dave Hansen wrote:
>> From: Dave Hansen <dave.hansen@linux.intel.com>
>> +
>> +If you believe that invlpg is being called too often, you can
>> +lower the tunable:
>> +
>> + /sys/debug/kernel/x86/tlb_single_page_flush_ceiling
>> +
>
> Whenever this tunable needs to be updated, most users will not know what
> a invlpg is and won't think in terms of pages either. How about making
> this in units of Kb instead? But then again most of those users won't be
> looking into tlb flushing issues anyways, so...
Yeah, talking about the instruction directly in the documentation is
probably going a bit far. I'll see if I can uplevel it a bit.
It's obviously not a big deal to change it to be pages vs. kb, but for
something that's as *COMPLETELY* developer-focused, I think we can keep
it in pages. We don't want users fooling with this.
> While obvious, tt should also mention that this does not apply to
> hugepages.
Good point.
next prev parent reply other threads:[~2014-03-07 17:19 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-06 0:45 [PATCH 0/7] x86: rework tlb range flushing code Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-06 0:45 ` [PATCH 1/7] x86: mm: clean up tlb " Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-07 0:16 ` Davidlohr Bueso
2014-03-07 0:16 ` Davidlohr Bueso
2014-03-07 0:51 ` Davidlohr Bueso
2014-03-07 0:51 ` Davidlohr Bueso
2014-03-07 0:57 ` Eric Boxer
2014-03-06 0:45 ` [PATCH 2/7] x86: mm: rip out complicated, out-of-date, buggy TLB flushing Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-06 0:45 ` [PATCH 3/7] x86: mm: fix missed global TLB flush stat Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-06 0:45 ` [PATCH 4/7] x86: mm: trace tlb flushes Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-06 0:45 ` [PATCH 5/7] x86: mm: new tunable for single vs full TLB flush Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-07 1:37 ` Davidlohr Bueso
2014-03-07 1:37 ` Davidlohr Bueso
2014-03-07 17:19 ` Dave Hansen [this message]
2014-03-07 17:19 ` Dave Hansen
2014-03-06 0:45 ` [PATCH 6/7] x86: mm: set TLB flush tunable to sane value Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-07 1:55 ` Davidlohr Bueso
2014-03-07 1:55 ` Davidlohr Bueso
2014-03-07 17:15 ` Dave Hansen
2014-03-07 17:15 ` Dave Hansen
2014-03-08 0:28 ` Davidlohr Bueso
2014-03-08 0:28 ` Davidlohr Bueso
2014-03-06 0:45 ` [PATCH 7/7] big time hack: instrument flush times Dave Hansen
2014-03-06 0:45 ` Dave Hansen
2014-03-07 0:15 ` [PATCH 0/7] x86: rework tlb range flushing code Davidlohr Bueso
2014-03-07 0:15 ` Davidlohr Bueso
-- strict thread matches above, loose matches on Subject: below --
2014-03-10 17:11 Dave Hansen
2014-03-10 17:11 ` [PATCH 5/7] x86: mm: new tunable for single vs full TLB flush Dave Hansen
2014-03-10 17:11 ` Dave Hansen
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