From: "Andralojc, WojciechX" <wojciechx.andralojc@intel.com>
To: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
Panu Matilainen <pmatilai@redhat.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v3] Patch introducing API to read/write Intel Architecture Model Specific Registers (MSR)...
Date: Fri, 22 Jan 2016 11:37:31 +0000 [thread overview]
Message-ID: <3FD2C4106EAA5C43838688C653B6E2AFDC37A3@IRSMSX103.ger.corp.intel.com> (raw)
In-Reply-To: <2601191342CEEE43887BDE71AB97725836AEEE54@irsmsx105.ger.corp.intel.com>
> -----Original Message-----
> From: Ananyev, Konstantin
> Sent: Friday, January 22, 2016 11:05 AM
> To: Panu Matilainen; Andralojc, WojciechX
> Cc: dev@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v3] Patch introducing API to read/write Intel
> Architecture Model Specific Registers (MSR)...
>
> > -----Original Message-----
> > From: Panu Matilainen [mailto:pmatilai@redhat.com]
> > Sent: Friday, January 22, 2016 10:06 AM
> > To: Ananyev, Konstantin; Andralojc, WojciechX
> > Cc: dev@dpdk.org
> > Subject: Re: [dpdk-dev] [PATCH v3] Patch introducing API to read/write Intel
> Architecture Model Specific Registers (MSR)...
> >
> > On 01/21/2016 12:51 PM, Ananyev, Konstantin wrote:
> > > Hi Panu,
> > >
> > >> -----Original Message-----
> > >> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Panu
> > >> Matilainen
> > >> Sent: Thursday, January 21, 2016 10:39 AM
> > >> To: Andralojc, WojciechX
> > >> Cc: dev@dpdk.org
> > >> Subject: Re: [dpdk-dev] [PATCH v3] Patch introducing API to read/write
> Intel Architecture Model Specific Registers (MSR)...
> > >>
> > >> On 01/21/2016 10:18 AM, Wojciech Andralojc wrote:
> > >>> Patch reworked.
> > >>>
> > >>> Signed-off-by: Wojciech Andralojc <wojciechx.andralojc@intel.com>
> > >>> ---
> > >>> lib/librte_eal/common/include/arch/x86/rte_msr.h | 88
> +++++++++++++++++
> > >>> lib/librte_eal/linuxapp/eal/Makefile | 1 +
> > >>> lib/librte_eal/linuxapp/eal/arch/x86/rte_msr.c | 116
> +++++++++++++++++++++++
> > >>> 3 files changed, 205 insertions(+)
> > >>> create mode 100644
> lib/librte_eal/common/include/arch/x86/rte_msr.h
> > >>> create mode 100644
> > >>> lib/librte_eal/linuxapp/eal/arch/x86/rte_msr.c
> > >>
> > >> This creates a new arch-specific public API, with rte_msr.h
> > >> installed as a public header and implementation in the library (as
> > >> opposed to inline), and so the new functions would have to be added
> > >> to rte_eal_version.map.
> > >>
> > >> However that is a bit of a problem since it only exists on IA
> > >> architectures, so it'd mean dummy entries in the version map for
> > >> all other architectures. All the other arch-specific APIs are
> > >> inline code so this is the first of its kind.
> > >
> > > My thought was:
> > > 1. implementation is linux specific (as I know not supposed to work under
> freebsd).
> > > 2. they are not supposed to be used at run-time cide-path, so no need to be
> inlined.
> >
> > Speed is not the only interesting attribute of inlining, inlined code
> > also effectively escapes the library ABI so it does not need
> > versioning / exporting.
> >
> > > 3. As I understand we plan to have a library that will use these functions
> anyway.
> >
> > Is this library going to be a generic or specific to Intel CPUs?
>
> As I understand - yes.
> It supposed to utilise new Intel chips CAT abilities.
> Wojciech, please correct me if I missed something here.
Konstantin, yes, you are right,
CAT enabling lib is Intel CPUs specific.
>
> > Also, if there are no other uses for the MSR API at the moment,
> > perhaps the best place for this code would be within that library anyway?
>
> Sounds good to me.
OK, sounds good.
Thank you both for your input.
>
> Konstantin
>
> >
> > > About dummy entries in the .map file: if we'll create a 'weak'
> > > generic implementation, that would just return an error - would it solve the
> issue?
> >
> > Sure it'd solve the issue of dummy entries in .map but people seemed
> > opposed to having a highly arch-specific API exposed to all architectures.
> >
> > - Panu -
> >
Wojciech Andralojc
prev parent reply other threads:[~2016-01-22 11:37 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-17 12:12 [dpdk-dev] [PATCH] Patch introducing API to read/write Intel Architecture Model Specific Registers (MSR), rte_msr_read and rte_msr_write functions Wojciech Andralojc
[not found] ` <3FD2C4106EAA5C43838688C653B6E2AFDB8422@IRSMSX103.ger.corp.intel.com>
2016-01-06 17:33 ` Jerin Jacob
2016-01-20 10:56 ` [dpdk-dev] [PATCH v2] Patch introducing API to read/write Intel Architecture Model Specific Registers (MSR) Wojciech Andralojc
2016-01-20 11:25 ` Ananyev, Konstantin
2016-01-21 8:18 ` [dpdk-dev] [PATCH v3] " Wojciech Andralojc
2016-01-21 9:34 ` Thomas Monjalon
2016-01-21 10:38 ` Panu Matilainen
2016-01-21 10:51 ` Ananyev, Konstantin
2016-01-22 10:05 ` Panu Matilainen
2016-01-22 11:05 ` Ananyev, Konstantin
2016-01-22 11:37 ` Andralojc, WojciechX [this message]
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