> > Hello Hatayama-san,
> >
> > Thank you for your work.
> >
> >> Performance Comparison:
> >>
> >> Sample Data
> >>
> >> Ideally, I must have measured the performance for many enough
> >> vmcores generated from machines that was actually running, but now
> >> I don't have enough sample vmcores, I couldn't do so. So this
> >> comparison doesn't answer question on I/O time improvement. This
> >> is TODO for now.
> >
> > I'll measure the performance for actual vmcores by makedumpfile.
> > Please wait for a while.
I measured the performance of makedumpfile for some vmcores.
Please see below.
Sample Data
To simulate a working server, I captured VMCOREs while almost all pages
were alloceted and filled with random data. (See attached file "fill_random.c")
I captured the VMCOREs of 5GB, 7.5GB and 10GB in the same condition.
How to measure
I measured the total execution time and the size of output file.
$ time makedumpfile --message-level 16 [-c|-l| ] vmcore dumpfile
Result
See attached file "result.txt".
This time, lzo's compression was the quickest, and lzo's compression ratio is
almost the same(only a bit worse) as zlib's.
It seems good, and I will merge the patch set into the makedumpfile.
What is your opinion, Dave?
Thanks.
KUMAGAI, Atsushi
>
> That's very helpful. Thanks in advance.
>
> But of course I'm also still looking for alternative way.
>
> Thanks.
> HATAYAMA, Daisuke
>
lzo zlib non-compress
5GBytes
total time(sec) 238 464 252
total time ratio(%) 94.4 184.1 100
output size(KBytes) 4812695 4771490 5156005
compression size ratio(%) 93.2 92.4 100
7.5GBytes
total time(sec) 358 685 376
total time ratio(%) 95.2 182.1 100
output size(KBytes) 7193681 7130501 7782665
compression size ratio(%) 92.4 91.6 100
10GBytes
total time(sec) 493 929 527
total time ratio(%) 93.5 176.3 100
output size(KBytes) 9980424 9932498 10460825
compression size ratio(%) 95.4 94.9 100
[about sample data]
Sample data is random, and it has deviation in compression ratio.
I show the number of pages below which were compressed.
(See attached patch "compressed_page_report.patch")
lzo zlib
5GByte
compressed page 120052 122238
non-compressed page 1505548 1503362
compression page ratio(%) 7.39 7.52
7.5GByte
compressed page 206481 209758
non-compressed page 2071919 2068642
compression page ratio(%) 9.06 9.21
10GByte
compressed page 160327 161229
non-compressed page 2783673 2782771
compression page ratio(%) 5.45 5.48
Attachment:
compressed_page_report.patch
Description: Binary data
#include <stdio.h>
#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <errno.h>
#include <string.h>
#include <sys/time.h>
#define MEGABYTES (1024*1024)
int pagefault_megabyte(char **ptr)
{
char *ptr_local;
int j;
ptr_local = *ptr;
srand((unsigned) time(NULL));
for (j = 0; j < MEGABYTES; j++, ptr_local++) {
memset(ptr_local, rand()%256, 1);
}
}
main(int argc, char *argv[])
{
int i, mem_mega_bytes;
char *ptr[1024*1024];
if (argc != 2) {
printf("Invalid param\n");
return 1;
}
mem_mega_bytes = atoi(argv[1]);
for (i = 0; i < mem_mega_bytes; i++) {
ptr[i] = malloc(MEGABYTES);
if (ptr[i] == NULL) {
printf("malloc error. (%s)\n", strerror(errno));
exit(1);
}
}
retry:
for (i = 0; i < mem_mega_bytes; i++) {
pagefault_megabyte(&ptr[i]);
}
goto retry;
}-- Crash-utility mailing list Crash-utility@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/crash-utility
