From: "Luis R. Rodriguez" <mcgrof@suse.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Casey Leedom" <leedom@chelsio.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Toshi Kani" <toshi.kani@hp.com>,
"Andy Lutomirski" <luto@amacapital.net>,
"Juergen Gross" <jgross@suse.com>,
"Tomi Valkeinen" <tomi.valkeinen@ti.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
linux-fbdev <linux-fbdev@vger.kernel.org>,
"Suresh Siddha" <sbsiddha@gmail.com>,
"Ingo Molnar" <mingo@elte.hu>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Dave Airlie" <airlied@redhat.com>,
"Antonino Daplas" <adaplas@gmail.com>,
"Jean-Christophe Plagniol-Villard" <plagnioj@jcrosoft.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"venkatesh.pallipadi@intel.com" <venkatesh.pallipadi@intel.com>,
"Stefan Bader" <stefan.bader@canonical.com>,
ville.syrjala@linux.intel.com,
"David Vrabel" <david.vrabel@citrix.com>,
"Jan Beulich" <jbeulich@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH v7 5/9] PCI: Add pci_iomap_wc() variants
Date: Fri, 26 Jun 2015 21:31:58 +0200 [thread overview]
Message-ID: <20150626193158.GJ3005@wotan.suse.de> (raw)
In-Reply-To: <1435272718.3822.7.camel@kernel.crashing.org>
On Fri, Jun 26, 2015 at 08:51:58AM +1000, Benjamin Herrenschmidt wrote:
> On Thu, 2015-06-25 at 21:40 +0000, Casey Leedom wrote:
> > Hhmmm, so what do PowerPC Drivers do when they want to take
> > advantage of Write Combining? Do their own Endian Swizzling
> > with the __raw_*() APIs?
>
> Yeah either, we need to fix our relaxed implementation (patch
> welcome :-)
Yikes, so although powerpc has useful heuristics to automatically
enable WC the default write ops have been nullifying its effects?
Shouldn't this have been blatantly obvious in performance benchmarks
and expectations? If not a change should give considerable performance
gains... If the WC was nullified on powerpc then the experience and
value of the heuristics have less value and even if they are going
to be only considered for userspace mmap() it should be taken with
a bit grain of salt it seems.
Luis
WARNING: multiple messages have this Message-ID (diff)
From: "Luis R. Rodriguez" <mcgrof@suse.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: "Casey Leedom" <leedom@chelsio.com>,
"Arnd Bergmann" <arnd@arndb.de>,
"Michael S. Tsirkin" <mst@redhat.com>,
"Bjorn Helgaas" <bhelgaas@google.com>,
"Toshi Kani" <toshi.kani@hp.com>,
"Andy Lutomirski" <luto@amacapital.net>,
"Juergen Gross" <jgross@suse.com>,
"Tomi Valkeinen" <tomi.valkeinen@ti.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
linux-fbdev <linux-fbdev@vger.kernel.org>,
"Suresh Siddha" <sbsiddha@gmail.com>,
"Ingo Molnar" <mingo@elte.hu>,
"Thomas Gleixner" <tglx@linutronix.de>,
"Daniel Vetter" <daniel.vetter@ffwll.ch>,
"Dave Airlie" <airlied@redhat.com>,
"Antonino Daplas" <adaplas@gmail.com>,
"Jean-Christophe Plagniol-Villard" <plagnioj@jcrosoft.com>,
"Dave Hansen" <dave.hansen@linux.intel.com>,
"venkatesh.pallipadi@intel.com" <venkatesh.pallipadi@intel.com>,
"Stefan Bader" <stefan.bader@canonical.com>,
ville.syrjala@linux.intel.com,
"David Vrabel" <david.vrabel@citrix.com>,
"Jan Beulich" <jbeulich@suse.com>,
"Roger Pau Monné" <roger.pau@citrix.com>
Subject: Re: [PATCH v7 5/9] PCI: Add pci_iomap_wc() variants
Date: Fri, 26 Jun 2015 19:31:58 +0000 [thread overview]
Message-ID: <20150626193158.GJ3005@wotan.suse.de> (raw)
In-Reply-To: <1435272718.3822.7.camel@kernel.crashing.org>
On Fri, Jun 26, 2015 at 08:51:58AM +1000, Benjamin Herrenschmidt wrote:
> On Thu, 2015-06-25 at 21:40 +0000, Casey Leedom wrote:
> > Hhmmm, so what do PowerPC Drivers do when they want to take
> > advantage of Write Combining? Do their own Endian Swizzling
> > with the __raw_*() APIs?
>
> Yeah either, we need to fix our relaxed implementation (patch
> welcome :-)
Yikes, so although powerpc has useful heuristics to automatically
enable WC the default write ops have been nullifying its effects?
Shouldn't this have been blatantly obvious in performance benchmarks
and expectations? If not a change should give considerable performance
gains... If the WC was nullified on powerpc then the experience and
value of the heuristics have less value and even if they are going
to be only considered for userspace mmap() it should be taken with
a bit grain of salt it seems.
Luis
WARNING: multiple messages have this Message-ID (diff)
From: "Luis R. Rodriguez" <mcgrof@suse.com>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Casey Leedom <leedom@chelsio.com>, Arnd Bergmann <arnd@arndb.de>,
"Michael S. Tsirkin" <mst@redhat.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Toshi Kani <toshi.kani@hp.com>,
Andy Lutomirski <luto@amacapital.net>,
Juergen Gross <jgross@suse.com>,
Tomi Valkeinen <tomi.valkeinen@ti.com>,
"linux-pci@vger.kernel.org" <linux-pci@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
linux-fbdev <linux-fbdev@vger.kernel.org>,
Suresh Siddha <sbsiddha@gmail.com>, Ingo Molnar <mingo@elte.hu>,
Thomas Gleixner <tglx@linutronix.de>,
Daniel Vetter <daniel.vetter@ffwll.ch>,
Dave Airlie <airlied@redhat.com>,
Antonino Daplas <adaplas@gmail.com>,
Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
"venkatesh.pallipadi@intel.com" <venkatesh.palli>
Subject: Re: [PATCH v7 5/9] PCI: Add pci_iomap_wc() variants
Date: Fri, 26 Jun 2015 21:31:58 +0200 [thread overview]
Message-ID: <20150626193158.GJ3005@wotan.suse.de> (raw)
In-Reply-To: <1435272718.3822.7.camel@kernel.crashing.org>
On Fri, Jun 26, 2015 at 08:51:58AM +1000, Benjamin Herrenschmidt wrote:
> On Thu, 2015-06-25 at 21:40 +0000, Casey Leedom wrote:
> > Hhmmm, so what do PowerPC Drivers do when they want to take
> > advantage of Write Combining? Do their own Endian Swizzling
> > with the __raw_*() APIs?
>
> Yeah either, we need to fix our relaxed implementation (patch
> welcome :-)
Yikes, so although powerpc has useful heuristics to automatically
enable WC the default write ops have been nullifying its effects?
Shouldn't this have been blatantly obvious in performance benchmarks
and expectations? If not a change should give considerable performance
gains... If the WC was nullified on powerpc then the experience and
value of the heuristics have less value and even if they are going
to be only considered for userspace mmap() it should be taken with
a bit grain of salt it seems.
Luis
next prev parent reply other threads:[~2015-06-26 19:32 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-06-19 22:08 [PATCH v7 0/9] pci: add pci_iomap_wc() and pci_ioremap_wc_bar() Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 1/9] pci: add pci_ioremap_wc_bar() Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 2/9] video: fbdev: i740fb: use arch_phys_wc_add() and pci_ioremap_wc_bar() Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 3/9] video: fbdev: kyrofb: " Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 4/9] video: fbdev: gxt4500: use pci_ioremap_wc_bar() for framebuffer Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 5/9] PCI: Add pci_iomap_wc() variants Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-23 22:42 ` Benjamin Herrenschmidt
2015-06-23 22:42 ` Benjamin Herrenschmidt
2015-06-23 22:42 ` Benjamin Herrenschmidt
2015-06-24 16:38 ` Luis R. Rodriguez
2015-06-24 16:38 ` Luis R. Rodriguez
2015-06-24 16:38 ` Luis R. Rodriguez
2015-06-24 22:05 ` Benjamin Herrenschmidt
2015-06-24 22:05 ` Benjamin Herrenschmidt
2015-06-24 22:05 ` Benjamin Herrenschmidt
2015-06-24 22:29 ` Luis R. Rodriguez
2015-06-24 22:29 ` Luis R. Rodriguez
2015-06-24 22:29 ` Luis R. Rodriguez
2015-06-24 23:38 ` Benjamin Herrenschmidt
2015-06-24 23:38 ` Benjamin Herrenschmidt
2015-06-24 23:38 ` Benjamin Herrenschmidt
2015-06-25 0:08 ` Luis R. Rodriguez
2015-06-25 0:08 ` Luis R. Rodriguez
2015-06-25 0:08 ` Luis R. Rodriguez
2015-06-25 0:52 ` Benjamin Herrenschmidt
2015-06-25 0:52 ` Benjamin Herrenschmidt
2015-06-25 0:52 ` Benjamin Herrenschmidt
2015-06-25 0:58 ` [Xen-devel] " Luis R. Rodriguez
2015-06-25 0:58 ` Luis R. Rodriguez
2015-06-25 0:58 ` Luis R. Rodriguez
2015-06-25 1:12 ` Benjamin Herrenschmidt
2015-06-25 1:12 ` Benjamin Herrenschmidt
2015-06-25 1:12 ` Benjamin Herrenschmidt
2015-06-25 15:01 ` Casey Leedom
2015-06-25 15:01 ` Casey Leedom
2015-06-25 20:44 ` Arnd Bergmann
2015-06-25 20:44 ` Arnd Bergmann
2015-06-25 20:44 ` Arnd Bergmann
2015-06-25 21:40 ` Casey Leedom
2015-06-25 21:40 ` Casey Leedom
2015-06-25 22:51 ` Benjamin Herrenschmidt
2015-06-25 22:51 ` Benjamin Herrenschmidt
2015-06-25 22:51 ` Benjamin Herrenschmidt
2015-06-26 19:31 ` Luis R. Rodriguez [this message]
2015-06-26 19:31 ` Luis R. Rodriguez
2015-06-26 19:31 ` Luis R. Rodriguez
2015-06-26 22:04 ` Benjamin Herrenschmidt
2015-06-26 22:04 ` Benjamin Herrenschmidt
2015-06-26 22:04 ` Benjamin Herrenschmidt
2015-06-26 22:41 ` Luis R. Rodriguez
2015-06-26 23:54 ` [Xen-devel] " Benjamin Herrenschmidt
2015-06-26 23:54 ` Benjamin Herrenschmidt
2015-06-26 23:54 ` [Xen-devel] " Benjamin Herrenschmidt
2015-06-27 1:16 ` Luis R. Rodriguez
2015-06-27 1:16 ` Luis R. Rodriguez
2015-06-27 1:16 ` [Xen-devel] " Luis R. Rodriguez
2015-06-26 2:02 ` Benjamin Herrenschmidt
2015-06-26 2:02 ` Benjamin Herrenschmidt
2015-06-26 2:02 ` Benjamin Herrenschmidt
2015-06-26 16:24 ` Casey Leedom
2015-06-26 16:24 ` Casey Leedom
2015-06-26 22:00 ` Benjamin Herrenschmidt
2015-06-26 22:00 ` Benjamin Herrenschmidt
2015-06-26 22:00 ` Benjamin Herrenschmidt
2015-07-02 18:49 ` Luis R. Rodriguez
2015-07-02 18:49 ` Luis R. Rodriguez
2015-07-02 18:49 ` Luis R. Rodriguez
2015-07-02 22:26 ` Benjamin Herrenschmidt
2015-07-02 22:26 ` Benjamin Herrenschmidt
2015-07-02 22:26 ` Benjamin Herrenschmidt
2015-07-03 0:14 ` Casey Leedom
2015-07-03 0:14 ` Casey Leedom
2015-07-03 0:14 ` Casey Leedom
2015-06-19 22:08 ` [PATCH v7 6/9] lib: devres: add pcim_iomap_wc() variants Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 7/9] video: fbdev: arkfb: use arch_phys_wc_add() and pci_iomap_wc() Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 8/9] video: fbdev: s3fb: " Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` [PATCH v7 9/9] video: fbdev: vt8623fb: " Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-19 22:08 ` Luis R. Rodriguez
2015-06-23 10:53 ` [PATCH v7 0/9] pci: add pci_iomap_wc() and pci_ioremap_wc_bar() Arnd Bergmann
2015-06-23 10:53 ` Arnd Bergmann
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