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* [Bug math/5782] New: Slow sine function for special values on AMD64 - second attempt
@ 2008-02-21 12:00 grugh at centrum dot cz
2008-02-21 13:17 ` [Bug math/5782] " grugh at centrum dot cz
0 siblings, 1 reply; 3+ messages in thread
From: grugh at centrum dot cz @ 2008-02-21 12:00 UTC (permalink / raw)
To: glibc-bugs
I would like to repost my previously deleted bug by (lazy IMHO)
carlos@codesoucery.com. The math sin function is at least 1000x slower on 64bit
distributions for special numbers (and carlos dosn't care about it).
I can't try it with CVS head, because I cannot connect to cvs through our firewall.
But even when I tried the latest snapshot, I couldn't build it (maybe another bug):
a - elf/dl-vdso.os
: /home/inova/projects/glibc/build/libc_pic.a
gcc -nostdlib -nostartfiles -r -o
/home/inova/projects/glibc/build/elf/librtld.map.o '-Wl,-('
/home/inova/projects/glibc/build/elf/dl-allobjs.os
/home/inova/projects/glibc/build/libc_pic.a -lgcc '-Wl,-)'
-Wl,-Map,/home/inova/projects/glibc/build/elf/librtld.mapT
/home/inova/projects/glibc/build/libc_pic.a(init-first.os):(.data+0x0): multiple
definition of `__libc_multiple_libcs'
/home/inova/projects/glibc/build/elf/dl-allobjs.os:/home/inova/projects/glibc/src/glibc-20080218/elf/rtld.c:641:
first defined here
/home/inova/projects/glibc/build/libc_pic.a(dl-addr.os): In function
`_dl_addr_inside_object':
/home/inova/projects/glibc/src/glibc-20080218/elf/dl-addr.c:158: multiple
definition of `_dl_addr_inside_object'
/home/inova/projects/glibc/build/elf/dl-allobjs.os:/home/inova/projects/glibc/src/glibc-20080218/elf/dl-open.c:700:
first defined here
collect2: ld returned 1 exit status
make[2]: *** [/home/inova/projects/glibc/build/elf/librtld.map] Error 1
make[2]: Leaving directory `/home/inova/projects/glibc/src/glibc-20080218/elf'
make[1]: *** [elf/subdir_lib] Error 2
make[1]: Leaving directory `/home/inova/projects/glibc/src/glibc-20080218'
make: *** [all] Error 2
Please, anyone with 64bit distribution and glibc CVS head, could you try the
attached example and post the time results of it? (or help me to build the
snapshot...)
Thank you
====== Original bug report ======================================
The math sin(double) function is in 64bit distribution (Kubuntu 7.10 AMD64 and
Fedora - unknown version) unreasonable slow (~400 microseconds on Atlon64 X2
4800+!!!) for some special values. In 32bit distribution is everything fine.
I captured some of those values:
0.93340582292648832662962377071381 0x3fedde75e36bb000
2.3328432680770916363144351635128 0x4002a9a9bb38add0
3.7439477503636453548097051680088 0x400df39ae0cdf500
3.9225160069792437411706487182528 0x400f615012801950
4.0711651639931289992091478779912 0x401048df854fdc20
4.7858438478542097982426639646292 0x401324b43fe92fc0
5.9840767662578002727968851104379 0x4017efb1d1df52a0
Example:
#include <math.h>
int main(int argc, char** argv) {
volatile double value = 0.93340582292648832662962377071381;
volatile double out;
int i;
for (i=0; i < 20000; i++)
out = sin(value);
return 0;
}
--
Summary: Slow sine function for special values on AMD64 - second
attempt
Product: glibc
Version: unspecified
Status: NEW
Severity: normal
Priority: P2
Component: math
AssignedTo: aj at suse dot de
ReportedBy: grugh at centrum dot cz
CC: glibc-bugs at sources dot redhat dot com
GCC host triplet: x86_64-unknown-linux-gnu
http://sourceware.org/bugzilla/show_bug.cgi?id=5782
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* [Bug math/5782] Slow sine function for special values on AMD64 - second attempt
2008-02-21 12:00 [Bug math/5782] New: Slow sine function for special values on AMD64 - second attempt grugh at centrum dot cz
@ 2008-02-21 13:17 ` grugh at centrum dot cz
0 siblings, 0 replies; 3+ messages in thread
From: grugh at centrum dot cz @ 2008-02-21 13:17 UTC (permalink / raw)
To: glibc-bugs
------- Additional Comments From grugh at centrum dot cz 2008-02-21 13:16 -------
sorry for duplict entry
--
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |INVALID
http://sourceware.org/bugzilla/show_bug.cgi?id=5782
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* [Bug math/5782] Slow sine function for special values on AMD64 - second attempt
[not found] <bug-5782-131@http.sourceware.org/bugzilla/>
@ 2014-07-02 7:19 ` fweimer at redhat dot com
0 siblings, 0 replies; 3+ messages in thread
From: fweimer at redhat dot com @ 2014-07-02 7:19 UTC (permalink / raw)
To: glibc-bugs
https://sourceware.org/bugzilla/show_bug.cgi?id=5782
Florian Weimer <fweimer at redhat dot com> changed:
What |Removed |Added
----------------------------------------------------------------------------
Flags| |security-
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2008-02-21 12:00 [Bug math/5782] New: Slow sine function for special values on AMD64 - second attempt grugh at centrum dot cz
2008-02-21 13:17 ` [Bug math/5782] " grugh at centrum dot cz
[not found] <bug-5782-131@http.sourceware.org/bugzilla/>
2014-07-02 7:19 ` fweimer at redhat dot com
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