| commit | 96e017495e6833adcbad84783e3c5eb685836bbf | |
| author | David Mosberger-Tang <davidm@hpl.hp.com> | |
| Thu, 28 Apr 2005 04:16:07 +0000 (27 21:16 -0700) | ||
| committer | Tony Luck <tony.luck@intel.com> | |
| Thu, 28 Apr 2005 04:16:07 +0000 (27 21:16 -0700) | ||
| tree | 41504d1ba4f94282d109224936ae6829109c3e6d | treesnapshot (tar.gz zip) |
| parent | 3c79c8b1d92a9ae3edf3cbcd2c43c553ee0f1d83 | commitdiff |
[IA64] On return from syscall, hint b7 with __kernel_syscall_via_epc().
Why is this a good idea? Clearing b7 to 0 is guaranteed to do us no
good and writing it with __kernel_syscall_via_epc() yields a 6 cycle
improvement _if_ the application performs another EPC-based system-
call without overwriting b7, which is not all that uncommon. Well
worth the minimal cost of 1 bundle of code.
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Why is this a good idea? Clearing b7 to 0 is guaranteed to do us no
good and writing it with __kernel_syscall_via_epc() yields a 6 cycle
improvement _if_ the application performs another EPC-based system-
call without overwriting b7, which is not all that uncommon. Well
worth the minimal cost of 1 bundle of code.
Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
| arch/ia64/kernel/entry.S | diffblobblamehistory |