Date: Tue, 5 May 2009 13:10:50 GMT From: Michel Henaut <michel.henaut@everyware.ch> To: freebsd-gnats-submit@FreeBSD.org Subject: kern/134231: performance issue Message-ID: <200905051310.n45DAorr065348@www.freebsd.org> Resent-Message-ID: <200905051320.n45DK3Og059450@freefall.freebsd.org>
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>Number: 134231
>Category: kern
>Synopsis: performance issue
>Confidential: no
>Severity: non-critical
>Priority: low
>Responsible: freebsd-bugs
>State: open
>Quarter:
>Keywords:
>Date-Required:
>Class: sw-bug
>Submitter-Id: current-users
>Arrival-Date: Tue May 05 13:20:02 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator: Michel Henaut
>Release: 5.5,6.2,6.3,6.4,7.0,7.1,7.2
>Organization:
everyware ltd
>Environment:
FreeBSD freebsd72-64.local 7.2-RELEASE FreeBSD 7.2-RELEASE
>Description:
We have an application (server statistics), which uses sysctl and kvm_read. We
discovered that the Cpu use of our collector increased by 80% between 6.2 and
7.2. A small test program calling 10'000 sysctl gives the following result:
6.2:
real 0m2.098s
user 0m0.000s
sys 0m2.073s
7.0:
real 0m4.352s
user 0m0.036s
sys 0m4.119s
Do you plan another way to get a sysctl resource other than the full scan done
in the different sysctl_find_oid. (use of tree instead of linked list).
regards
>How-To-Repeat:
#include <stdio.h>
#include <sys/types.h>
#include <sys/sysctl.h>
int main()
{
int mib[4], st, nprocs;
size_t size;
int temp_op;
int op = KERN_PROC_ALL;
int arg = 0;
int i;
mib[0] = CTL_KERN;
mib[1] = KERN_PROC;
mib[2] = op;
mib[3] = arg;
temp_op = op & ~KERN_PROC_INC_THREAD;
for (i = 0; i < 10000; i++) {
st = sysctl(mib, 3, NULL, &size, NULL, 0);
if (st == -1) {
fprintf(stderr, "sysctl error\n");
exit(1);
}
}
exit(0);
}
>Fix:
>Release-Note:
>Audit-Trail:
>Unformatted:
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