From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>, Alex Shi <alex.shi@linaro.org>,
Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Fengguang Wu <fengguang.wu@intel.com>,
H Peter Anvin <hpa@zytor.com>, Linux-X86 <x86@kernel.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/5] mm: x86: Revisit tlb_flushall_shift tuning for page flushes except on IvyBridge
Date: Thu, 09 Jan 2014 15:00:51 -0500 [thread overview]
Message-ID: <52CEFFF3.9010709@redhat.com> (raw)
In-Reply-To: <1389278098-27154-6-git-send-email-mgorman@suse.de>
On 01/09/2014 09:34 AM, Mel Gorman wrote:
> There was a large ebizzy performance regression that was bisected to commit
> 611ae8e3 (x86/tlb: enable tlb flush range support for x86). The problem
> was related to the tlb_flushall_shift tuning for IvyBridge which was
> altered. The problem is that it is not clear if the tuning values for each
> CPU family is correct as the methodology used to tune the values is unclear.
>
> This patch uses a conservative tlb_flushall_shift value for all CPU families
> except IvyBridge so the decision can be revisited if any regression is found
> as a result of this change. IvyBridge is an exception as testing with one
> methodology determined that the value of 2 is acceptable. Details are in the
> changelog for the patch "x86: mm: Change tlb_flushall_shift for IvyBridge".
>
> One important aspect of this to watch out for is Xen. The original commit
> log mentioned large performance gains on Xen. It's possible Xen is more
> sensitive to this value if it flushes small ranges of pages more frequently
> than workloads on bare metal typically do.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
WARNING: multiple messages have this Message-ID (diff)
From: Rik van Riel <riel@redhat.com>
To: Mel Gorman <mgorman@suse.de>, Alex Shi <alex.shi@linaro.org>,
Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>,
Thomas Gleixner <tglx@linutronix.de>,
Andrew Morton <akpm@linux-foundation.org>,
Fengguang Wu <fengguang.wu@intel.com>,
H Peter Anvin <hpa@zytor.com>, Linux-X86 <x86@kernel.org>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/5] mm: x86: Revisit tlb_flushall_shift tuning for page flushes except on IvyBridge
Date: Thu, 09 Jan 2014 15:00:51 -0500 [thread overview]
Message-ID: <52CEFFF3.9010709@redhat.com> (raw)
In-Reply-To: <1389278098-27154-6-git-send-email-mgorman@suse.de>
On 01/09/2014 09:34 AM, Mel Gorman wrote:
> There was a large ebizzy performance regression that was bisected to commit
> 611ae8e3 (x86/tlb: enable tlb flush range support for x86). The problem
> was related to the tlb_flushall_shift tuning for IvyBridge which was
> altered. The problem is that it is not clear if the tuning values for each
> CPU family is correct as the methodology used to tune the values is unclear.
>
> This patch uses a conservative tlb_flushall_shift value for all CPU families
> except IvyBridge so the decision can be revisited if any regression is found
> as a result of this change. IvyBridge is an exception as testing with one
> methodology determined that the value of 2 is acceptable. Details are in the
> changelog for the patch "x86: mm: Change tlb_flushall_shift for IvyBridge".
>
> One important aspect of this to watch out for is Xen. The original commit
> log mentioned large performance gains on Xen. It's possible Xen is more
> sensitive to this value if it flushes small ranges of pages more frequently
> than workloads on bare metal typically do.
>
> Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
next prev parent reply other threads:[~2014-01-09 20:01 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-01-09 14:34 [PATCH 0/5] Fix ebizzy performance regression due to X86 TLB range flush v3 Mel Gorman
2014-01-09 14:34 ` Mel Gorman
2014-01-09 14:34 ` [PATCH 1/5] x86: mm: Account for TLB flushes only when debugging Mel Gorman
2014-01-09 14:34 ` Mel Gorman
2014-01-09 19:43 ` Rik van Riel
2014-01-09 19:43 ` Rik van Riel
2014-01-16 11:12 ` [PATCH] mm: vmstat: Do not display stats for TLB flushes unless debugging Mel Gorman
2014-01-16 11:12 ` Mel Gorman
2014-01-16 12:25 ` Rik van Riel
2014-01-16 12:25 ` Rik van Riel
2014-01-16 23:22 ` David Rientjes
2014-01-16 23:22 ` David Rientjes
2014-01-17 8:53 ` Mel Gorman
2014-01-17 8:53 ` Mel Gorman
2014-01-09 14:34 ` [PATCH 2/5] x86: mm: Clean up inconsistencies when flushing TLB ranges Mel Gorman
2014-01-09 14:34 ` Mel Gorman
2014-01-09 19:47 ` Rik van Riel
2014-01-09 19:47 ` Rik van Riel
2014-01-09 14:34 ` [PATCH 3/5] x86: mm: Eliminate redundant page table walk during TLB range flushing Mel Gorman
2014-01-09 14:34 ` Mel Gorman
2014-01-09 19:49 ` Rik van Riel
2014-01-09 19:49 ` Rik van Riel
2014-01-09 14:34 ` [PATCH 4/5] x86: mm: Change tlb_flushall_shift for IvyBridge Mel Gorman
2014-01-09 14:34 ` Mel Gorman
2014-01-09 19:59 ` Rik van Riel
2014-01-09 19:59 ` Rik van Riel
2014-01-09 14:34 ` [PATCH 5/5] mm: x86: Revisit tlb_flushall_shift tuning for page flushes except on IvyBridge Mel Gorman
2014-01-09 14:34 ` Mel Gorman
2014-01-09 20:00 ` Rik van Riel [this message]
2014-01-09 20:00 ` Rik van Riel
2014-01-09 21:39 ` [PATCH 0/5] Fix ebizzy performance regression due to X86 TLB range flush v3 Davidlohr Bueso
2014-01-09 21:39 ` Davidlohr Bueso
2014-01-16 14:01 ` [TLB range flush] +34.7% hackbench.throughput Fengguang Wu
2014-01-16 18:49 ` Mel Gorman
2014-01-16 18:49 ` Mel Gorman
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=52CEFFF3.9010709@redhat.com \
--to=riel@redhat.com \
--cc=akpm@linux-foundation.org \
--cc=alex.shi@linaro.org \
--cc=fengguang.wu@intel.com \
--cc=hpa@zytor.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=mgorman@suse.de \
--cc=mingo@kernel.org \
--cc=tglx@linutronix.de \
--cc=torvalds@linux-foundation.org \
--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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.