From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from e24smtp04.br.ibm.com (e24smtp04.br.ibm.com [32.104.18.25]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (Client CN "e24smtp04.br.ibm.com", Issuer "GeoTrust SSL CA" (not verified)) by ozlabs.org (Postfix) with ESMTPS id 995E42C0155 for ; Tue, 23 Apr 2013 05:30:11 +1000 (EST) Received: from /spool/local by e24smtp04.br.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Mon, 22 Apr 2013 16:30:04 -0300 Received: from d24relay01.br.ibm.com (d24relay01.br.ibm.com [9.8.31.16]) by d24dlp02.br.ibm.com (Postfix) with ESMTP id E25401DC0060 for ; Mon, 22 Apr 2013 15:30:00 -0400 (EDT) Received: from d24av04.br.ibm.com (d24av04.br.ibm.com [9.8.31.97]) by d24relay01.br.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id r3MJRKRD2785484 for ; Mon, 22 Apr 2013 16:27:20 -0300 Received: from d24av04.br.ibm.com (loopback [127.0.0.1]) by d24av04.br.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id r3MHTjNE026031 for ; Mon, 22 Apr 2013 14:29:45 -0300 Message-ID: <51758F9D.4010108@linux.vnet.ibm.com> Date: Mon, 22 Apr 2013 16:29:33 -0300 From: Adhemerval Zanella MIME-Version: 1.0 To: linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH] [RFC] powerpc: Add VDSO version of time References: <5148C2B3.6010408@linux.vnet.ibm.com> <20130419083835.37f1c180@kryten> In-Reply-To: <20130419083835.37f1c180@kryten> Content-Type: text/plain; charset=ISO-8859-1 Cc: Anton Blanchard List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , On 04/18/2013 07:38 PM, Anton Blanchard wrote: > Since you are only reading one long you shouldn't need to check the > update count and loop, you will always see a consistent value. The > system call version of time() just does an unprotected load for example. Fixed. > With the above change and with Michael's comments covered (decent > changelog entry and Signed-off-by): > > Acked-by: Anton Blanchard Thanks for the review, below the updated patch: From: Adhemerval Zanella This patch implement the time syscall as vDSO. The performance speedups are: Baseline PPC32: 380 nsec Baseline PPC64: 350 nsec vdso PPC32: 20 nsec vsdo PPC64: 20 nsec Tested on 64 bit build with both 32 bit and 64 bit userland. Acked-by: Anton Blanchard Signed-off-by: Adhemerval Zanella --- arch/powerpc/kernel/vdso.c | 4 ++++ arch/powerpc/kernel/vdso32/gettimeofday.S | 26 ++++++++++++++++++++++++++ arch/powerpc/kernel/vdso32/vdso32.lds.S | 1 + arch/powerpc/kernel/vdso64/gettimeofday.S | 26 ++++++++++++++++++++++++++ arch/powerpc/kernel/vdso64/vdso64.lds.S | 1 + 5 files changed, 58 insertions(+), 0 deletions(-) diff --git a/arch/powerpc/kernel/vdso.c b/arch/powerpc/kernel/vdso.c index 1b2076f..d4f463a 100644 --- a/arch/powerpc/kernel/vdso.c +++ b/arch/powerpc/kernel/vdso.c @@ -113,6 +113,10 @@ static struct vdso_patch_def vdso_patches[] = { CPU_FTR_USE_TB, 0, "__kernel_get_tbfreq", NULL }, + { + CPU_FTR_USE_TB, 0, + "__kernel_time", NULL + }, }; /* diff --git a/arch/powerpc/kernel/vdso32/gettimeofday.S b/arch/powerpc/kernel/vdso32/gettimeofday.S index 4ee09ee..27e2f62 100644 --- a/arch/powerpc/kernel/vdso32/gettimeofday.S +++ b/arch/powerpc/kernel/vdso32/gettimeofday.S @@ -181,6 +181,32 @@ V_FUNCTION_END(__kernel_clock_getres) /* + * Exact prototype of time() + * + * time_t time(time *t); + * + */ +V_FUNCTION_BEGIN(__kernel_time) + .cfi_startproc + mflr r12 + .cfi_register lr,r12 + + mr r11,r3 /* r11 holds t */ + bl __get_datapage@local + mr r9, r3 /* datapage ptr in r9 */ + + lwz r3,STAMP_XTIME+TSPEC_TV_SEC(r9) + + cmplwi r11,0 /* check if t is NULL */ + beq 2f + stw r3,0(r11) /* store result at *t */ +2: mtlr r12 + crclr cr0*4+so + blr + .cfi_endproc +V_FUNCTION_END(__kernel_time) + +/* * This is the core of clock_gettime() and gettimeofday(), * it returns the current time in r3 (seconds) and r4. * On entry, r7 gives the resolution of r4, either USEC_PER_SEC diff --git a/arch/powerpc/kernel/vdso32/vdso32.lds.S b/arch/powerpc/kernel/vdso32/vdso32.lds.S index 43200ba..f223409 100644 --- a/arch/powerpc/kernel/vdso32/vdso32.lds.S +++ b/arch/powerpc/kernel/vdso32/vdso32.lds.S @@ -150,6 +150,7 @@ VERSION #ifdef CONFIG_PPC64 __kernel_getcpu; #endif + __kernel_time; local: *; }; diff --git a/arch/powerpc/kernel/vdso64/gettimeofday.S b/arch/powerpc/kernel/vdso64/gettimeofday.S index e97a9a0..a76b4af 100644 --- a/arch/powerpc/kernel/vdso64/gettimeofday.S +++ b/arch/powerpc/kernel/vdso64/gettimeofday.S @@ -164,6 +164,32 @@ V_FUNCTION_BEGIN(__kernel_clock_getres) .cfi_endproc V_FUNCTION_END(__kernel_clock_getres) +/* + * Exact prototype of time() + * + * time_t time(time *t); + * + */ +V_FUNCTION_BEGIN(__kernel_time) + .cfi_startproc + mflr r12 + .cfi_register lr,r12 + + mr r11,r3 /* r11 holds t */ + bl V_LOCAL_FUNC(__get_datapage) + + ld r4,STAMP_XTIME+TSPC64_TV_SEC(r3) + + cmpldi r11,0 /* check if t is NULL */ + beq 2f + std r4,0(r11) /* store result at *t */ +2: mtlr r12 + crclr cr0*4+so + mr r3,r4 + blr + .cfi_endproc +V_FUNCTION_END(__kernel_time) + /* * This is the core of clock_gettime() and gettimeofday(), diff --git a/arch/powerpc/kernel/vdso64/vdso64.lds.S b/arch/powerpc/kernel/vdso64/vdso64.lds.S index e6c1758..e486381 100644 --- a/arch/powerpc/kernel/vdso64/vdso64.lds.S +++ b/arch/powerpc/kernel/vdso64/vdso64.lds.S @@ -147,6 +147,7 @@ VERSION __kernel_sync_dicache_p5; __kernel_sigtramp_rt64; __kernel_getcpu; + __kernel_time; local: *; };