by Vitaly Kuznetsov

[permalink] [raw]

Subject: Re: [PATCH v10 0/9] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

Ingo Molnar <[email protected]> writes:

> * Vitaly Kuznetsov <[email protected]> wrote:
>
>> Vitaly Kuznetsov <[email protected]> writes:
>>
>> > Changes since v9:
>> > - Rebase to 4.13-rc3.
>> > - Drop PATCH1 as it was already taken by Greg to char-misc tree. There're no
>> > functional dependencies on this patch so the series can go through a different tree
>> > (and it actually belongs to x86 if I got Ingo's comment right).
>> > - Add in missing void return type in PATCH1 [Colin King, Ingo Molnar, Greg KH]
>> > - A few minor fixes in what is now PATCH7: add pr_fmt, tiny style fix in
>> > hyperv_flush_tlb_others() [Andy Shevchenko]
>> > - Fix "error: implicit declaration of function 'virt_to_phys'" in PATCH2
>> > reported by kbuild test robot (#include <asm/io.h>)
>> > - Add Steven's 'Reviewed-by:' to PATCH9.
>>
>> Thomas, Ingo, Greg,
>>
>> do I get it right that the intention is to take this series through x86
>> tree? (See: https://www.spinics.net/lists/kernel/msg2561174.html) If so,
>> is there anything else I need to do to get it accepted?
>
> Yeah, the patches are arch/x86/-heavy, so that would be the ideal workflow - it's
> just that the series coincided with x86 maintainers vacation time!
>
> I've picked them up now into tip:x86/platform (they look good to me) and will push
> them out after some testing.
>

Great, thanks!

--
Vitaly

2017-08-10 16:03:19

[permalink] [raw]

Subject: Re: [PATCH v10 0/9] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

#include <pthread.h>
#include <stdio.h>
#include <sys/mman.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <unistd.h>

#define nthreads 48
#define pagecount 16384
#define nrounds 1000
#define nchunks 20
#define PAGE_SIZE 4096

int fd;
unsigned long v;

void *threadf(void *ptr)
{
unsigned long *addr[nchunks];
int i, j, k;
struct timespec ts = {0};
int ret;

ts.tv_nsec = random() % 1024;

for (j = 0; j < nrounds; j++) {
for (i = 0; i < nchunks; i++) {
addr[i] = mmap(NULL, PAGE_SIZE * pagecount, PROT_READ, MAP_SHARED, fd, i * PAGE_SIZE);
if (addr[i] == MAP_FAILED) {
fprintf(stderr, "mmap\n");
exit(1);
}
}

nanosleep(&ts, NULL);

for (i = 0; i < nchunks; i++) {
v += *addr[i];
}

nanosleep(&ts, NULL);

for (i = 0; i < nchunks; i++) {
munmap(addr[i], PAGE_SIZE * pagecount);
}
}
}

int main(int argc, char *argv[]) {
pthread_t thr[nthreads];
int i;

srandom(time(NULL));

if (argc < 2) {
fprintf(stderr, "usage: %s <some-big-file>\n", argv[0]);
exit(1);
}

fd = open(argv[1], O_RDONLY);
if (fd < 0) {
fprintf(stderr, "open\n");
exit(1);
}

for (i = 0; i < nthreads; i++) {
if(pthread_create(&thr[i], NULL, threadf, NULL)) {
fprintf(stderr, "pthread_create\n");
exit(1);
}
}

for (i = 0; i < nthreads; i++) {
if(pthread_join(thr[i], NULL)) {
fprintf(stderr, "pthread_join\n");
exit(1);
}
}

return 0;
}

Attachments:

pthread_mmap.c (1.51 kB)

2017-11-06 08:45:55

by Wanpeng Li

[permalink] [raw]

Subject: Re: [PATCH v10 0/9] Hyper-V: paravirtualized remote TLB flushing and hypercall improvements

2017-08-03 0:09 GMT+08:00 Vitaly Kuznetsov <[email protected]>:
> Changes since v9:
> - Rebase to 4.13-rc3.
> - Drop PATCH1 as it was already taken by Greg to char-misc tree. There're no
> functional dependencies on this patch so the series can go through a different tree
> (and it actually belongs to x86 if I got Ingo's comment right).
> - Add in missing void return type in PATCH1 [Colin King, Ingo Molnar, Greg KH]
> - A few minor fixes in what is now PATCH7: add pr_fmt, tiny style fix in
> hyperv_flush_tlb_others() [Andy Shevchenko]
> - Fix "error: implicit declaration of function 'virt_to_phys'" in PATCH2
> reported by kbuild test robot (#include <asm/io.h>)
> - Add Steven's 'Reviewed-by:' to PATCH9.
>
> Original description:
>
> Hyper-V supports hypercalls for doing local and remote TLB flushing and
> gives its guests hints when using hypercall is preferred. While doing
> hypercalls for local TLB flushes is probably not practical (and is not
> being suggested by modern Hyper-V versions) remote TLB flush with a
> hypercall brings significant improvement.
>
> To test the series I wrote a special 'TLB trasher': on a 16 vCPU guest I
> was creating 32 threads which were doing 100000 mmap/munmaps each on some
> big file. Here are the results:
>
> Before:
> # time ./pthread_mmap ./randfile
> real 3m33.118s
> user 0m3.698s
> sys 3m16.624s
>
> After:
> # time ./pthread_mmap ./randfile
> real 2m19.920s
> user 0m2.662s
> sys 2m9.948s
>
> This series brings a number of small improvements along the way: fast
> hypercall implementation and using it for event signaling, rep hypercalls
> implementation, hyperv tracing subsystem (which only traces the newly added
> remote TLB flush for now).
>

Hi Vitaly,

Could you attach your benchmark? I'm interested in to try the
implementation in paravirt kvm.

Regards,
Wanpeng Li

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