I agree !,just i think the problem is still there,memcpy is indeed faster
in kernel than in user,i've tried both ways .
schedule might be to blame.
2018-07-09 22:04 GMT+08:00 Himanshu Jha :
> Hi Bing,
>
> On Sun, Jul 08, 2018 at 10:03:48PM +0800, bing zhu wrote:
> > void *p = malloc(4096 * max);
Hi All Thx for your answers ... Great learning... I will reread them
and understand better slowly and thoroughly.
On Sun 8 Jul, 2018, 11:20 PM , wrote:
> On Sun, 08 Jul 2018 11:21:08 +0530, inventsekar said:
>
> > I read this page few times but I am unable to understand what's Linus's
> >
CC'ing kernel newbies for anyone else trying to learn how linux-next
works.
On Fri, Jul 06, 2018 at 11:49:51AM -0400, Steven Rostedt wrote:
> On Fri, 6 Jul 2018 23:42:13 +0900
> Sergey Senozhatsky wrote:
>
> > On (07/06/18 15:47), Arnd Bergmann wrote:
> > [..]
> > > Fixes: bfe80ed3d7c7
On Tue, 10 Jul 2018 09:42:03 +1000, "Tobin C. Harding" said:
> I was under the impression that each maintainer constantly rebased their
> next branches and that was why one has to checkout the tagged linux-next
> each day instead of just pulling.
Close, but no cigar. The maintainers don't
On Tue, 10 Jul 2018 09:42:03 +1000
"Tobin C. Harding" wrote:
> Steve if you do not rebase your next branch and the branch ends up
> containing fixes to patches like the above doesn't this mean that when
> you do a pull request to Linus the branch you are asking to be pulled
> will be too 'dirty'
On 07/09/2018 12:17 PM, valdis.kletni...@vt.edu wrote:
> Linux doesn't have a "filesystem bus".
of course not. i mispoke
--
So many immigrant groups have swept through our town
that Brooklyn, like Atlantis, reaches mythological
proportions in the mind of the world - RI Safir 1998
can you show all code kernel and userspace ?
Kernel compile options are optimized, very different from userspace.
you can use the same object (memcpy.o) to link userspace program and kernel
module.
-原始邮件-
发件人:"bing zhu"
发送时间:2018-07-08 22:03:48 (星期日)
收件人: "Valdis Kletnieks"
抄送:
in kernel you should use this func:
static unsigned long usec(void)
{
struct timeval tv;
do_gettimeofday();
return (unsigned long)tv.tv_sec * 100 + tv.tv_usec;
}
2018-07-09 15:54 GMT+08:00 袁建鹏 :
> can you show all code kernel and userspace ?
>
> Kernel compile
On Mon, 09 Jul 2018 19:34:44 +0530, Himanshu Jha said:
> I think for these benchmarking stuff, to evaluate the cycles and time
> correctly you should use the __rdtscp(more info at "AMD64 Architecture
> Programmerâs Manual Volume 3: General-Purpose and System Instructions"
> Pg 401)
Just beware
On Mon, 09 Jul 2018 09:30:51 -0400, Ruben Safir said:
> On 07/08/2018 04:44 PM, valdis.kletni...@vt.edu wrote:
> > Error while parsing statement., What is a "filesystem bus" and when does it
> > issue a HW interrupt?
> You have a hard drive on the system bus and it sends interupts...
That's
On 07/08/2018 04:44 PM, valdis.kletni...@vt.edu wrote:
> Error while parsing statement., What is a "filesystem bus" and when does it
> issue a HW interrupt?
You have a hard drive on the system bus and it sends interupts...
Not to mention other devices like network cards, GPUs, Firewire, express
Hi Bing,
On Sun, Jul 08, 2018 at 10:03:48PM +0800, bing zhu wrote:
> void *p = malloc(4096 * max);
> start = usec();
> for (i = 0; i < max; i++) {
> memcpy(p + i * 4096, page, 4096);
> }
> end = usec();
> printf("%s : %d time use %lu us \n", __func__, max,end - start）;
>
> static unsigned long
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