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authorChristian Borntraeger <borntraeger@de.ibm.com>2017-06-19 10:59:40 +0200
committerStefan Liebler <stli@linux.vnet.ibm.com>2017-06-19 10:59:40 +0200
commit35810f5ccf735d8df0a783bc6ed5fbe455e64876 (patch)
treeac4dbf1066e2d624fe5bd52bce2c2ebda11fb951 /include/des.h
parent52243b520e2d336431ea410ef3aa1f766642f1d2 (diff)
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s390: optimize syscall function
Since kernel 2.6.0 all Linux version accept the system call number
in register 1 for svc 0. There is no need to have special handling
that uses EX for system calls < 256. This will simplify and speed
up that code.

A microbenchmark doing "syscall(__NR_getpid);" in a loops gets faster
by ~12%.

        * sysdeps/unix/sysv/linux/s390/s390-32/syscall.S: Simplify
        code by always using SVC 0 instead of EX.
        * sysdeps/unix/sysv/linux/s390/s390-64/syscall.S: Likewise.
Diffstat (limited to 'include/des.h')
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