From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
To: Florian Weimer <fw@deneb.enyo.de>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH 6/7] linux: Refactor sched_getcpu in terms of getcpu
Date: Mon, 02 Dec 2019 14:00:00 -0000 [thread overview]
Message-ID: <22ce01a8-9f61-4588-bb50-1d3aa4a302e1@linaro.org> (raw)
In-Reply-To: <87y2vwdt1g.fsf@mid.deneb.enyo.de>
On 01/12/2019 11:22, Florian Weimer wrote:
> * Adhemerval Zanella:
>
>> diff --git a/sysdeps/unix/sysv/linux/sched_getcpu.c b/sysdeps/unix/sysv/linux/sched_getcpu.c
>> index 65dd9fdda7..3646c8b713 100644
>> --- a/sysdeps/unix/sysv/linux/sched_getcpu.c
>> +++ b/sysdeps/unix/sysv/linux/sched_getcpu.c
>> @@ -17,23 +17,11 @@
>>
>> #include <errno.h>
>> #include <sched.h>
>> -#include <sysdep.h>
>> -
>> -#ifdef HAVE_GETCPU_VSYSCALL
>> -# define HAVE_VSYSCALL
>> -#endif
>> -#include <sysdep-vdso.h>
>>
>> int
>> sched_getcpu (void)
>> {
>> -#ifdef __NR_getcpu
>> unsigned int cpu;
>> - int r = INLINE_VSYSCALL (getcpu, 3, &cpu, NULL, NULL);
>> -
>> + int r = __getcpu (&cpu, NULL);
>> return r == -1 ? r : cpu;
>> -#else
>> - __set_errno (ENOSYS);
>> - return -1;
>> -#endif
>> }
>
> I wonder if the current state is a useful performance optimization.
>
I thought about that, another option would be to create an internal
header with a static inline implementation where both sched_getcpu
and getcpu will use and thus removing the function call overhead
while continuing to provide only one code that issue the vDSO/syscall.
next prev parent reply other threads:[~2019-12-02 14:00 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-29 21:03 [PATCH 1/7] linux: Update x86 vDSO symbols Adhemerval Zanella
2019-11-29 21:03 ` [PATCH 6/7] linux: Refactor sched_getcpu in terms of getcpu Adhemerval Zanella
2019-12-01 14:22 ` Florian Weimer
2019-12-02 14:00 ` Adhemerval Zanella [this message]
2019-12-03 13:56 ` [PATCH v2] linux: Add inline getcpu implementation for sched_getcpu and getcpu Adhemerval Zanella
2019-11-29 21:03 ` [PATCH 3/7] Remove vDSO support from make-syscall.sh Adhemerval Zanella
2019-11-29 21:03 ` [PATCH 2/7] x86: Make x32 use x86 time implementation Adhemerval Zanella
2019-11-29 21:03 ` [PATCH 7/7] elf: Move vDSO setup to rtld Adhemerval Zanella
2019-11-29 21:03 ` [PATCH 4/7] linux: Update mips vDSO symbols Adhemerval Zanella
2019-11-29 21:03 ` [PATCH 5/7] elf: Enable relro for static build Adhemerval Zanella
2019-12-01 9:55 ` Florian Weimer
2019-12-02 13:57 ` Adhemerval Zanella
2019-12-02 18:25 ` Florian Weimer
2019-12-02 18:54 ` Adhemerval Zanella
2019-12-02 19:03 ` Florian Weimer
2019-12-02 19:33 ` Adhemerval Zanella
2019-12-03 13:53 ` [PATCH v2] " Adhemerval Zanella
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