Re: [RFT PATCH v1 6/7] amd64: avoid saving and restoring FPSIMD registers until threads access them

2013-09-30 Thread Will Deacon
On Fri, Sep 27, 2013 at 03:20:10PM +0100, Jiang Liu wrote: > On 09/27/2013 06:59 PM, Will Deacon wrote: > > On Fri, Sep 27, 2013 at 09:04:46AM +0100, Jiang Liu wrote: > >> diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c > >> index 267e54a..a81af5f 100644 > >> ---

Re: [RFT PATCH v1 6/7] amd64: avoid saving and restoring FPSIMD registers until threads access them

2013-09-30 Thread Will Deacon
On Fri, Sep 27, 2013 at 03:20:10PM +0100, Jiang Liu wrote: On 09/27/2013 06:59 PM, Will Deacon wrote: On Fri, Sep 27, 2013 at 09:04:46AM +0100, Jiang Liu wrote: diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index 267e54a..a81af5f 100644 ---

Re: [RFT PATCH v1 6/7] amd64: avoid saving and restoring FPSIMD registers until threads access them

2013-09-27 Thread Jiang Liu
On 09/27/2013 06:59 PM, Will Deacon wrote: > On Fri, Sep 27, 2013 at 09:04:46AM +0100, Jiang Liu wrote: >> From: Jiang Liu >> >> Use PF_USED_MATH flag to mark whether the thread has accessed any FPSIMD >> registers, so we could avoid saving and restroing FPSIMD registers until >> threads access

Re: [RFT PATCH v1 6/7] amd64: avoid saving and restoring FPSIMD registers until threads access them

2013-09-27 Thread Will Deacon
On Fri, Sep 27, 2013 at 09:04:46AM +0100, Jiang Liu wrote: > From: Jiang Liu > > Use PF_USED_MATH flag to mark whether the thread has accessed any FPSIMD > registers, so we could avoid saving and restroing FPSIMD registers until > threads access them. This may improve performance when lazy

Re: [RFT PATCH v1 6/7] amd64: avoid saving and restoring FPSIMD registers until threads access them

2013-09-27 Thread Will Deacon
On Fri, Sep 27, 2013 at 09:04:46AM +0100, Jiang Liu wrote: From: Jiang Liu jiang@huawei.com Use PF_USED_MATH flag to mark whether the thread has accessed any FPSIMD registers, so we could avoid saving and restroing FPSIMD registers until threads access them. This may improve performance

Re: [RFT PATCH v1 6/7] amd64: avoid saving and restoring FPSIMD registers until threads access them

2013-09-27 Thread Jiang Liu
On 09/27/2013 06:59 PM, Will Deacon wrote: On Fri, Sep 27, 2013 at 09:04:46AM +0100, Jiang Liu wrote: From: Jiang Liu jiang@huawei.com Use PF_USED_MATH flag to mark whether the thread has accessed any FPSIMD registers, so we could avoid saving and restroing FPSIMD registers until threads