From: Paul Mackerras Date: Mon, 27 Oct 2008 23:56:03 +0000 (+0000) Subject: powerpc: Improve resolution of VDSO clock_gettime X-Git-Tag: v2.6.29-rc1~574^2~129 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=597bc5c00b666fe123abb0af64f6e86f7ab72a90;p=pandora-kernel.git powerpc: Improve resolution of VDSO clock_gettime Currently the clock_gettime implementation in the VDSO produces a result with microsecond resolution for the cases that are handled without a system call, i.e. CLOCK_REALTIME and CLOCK_MONOTONIC. The nanoseconds field of the result is obtained by computing a microseconds value and multiplying by 1000. This changes the code in the VDSO to do the computation for clock_gettime with nanosecond resolution. That means that the resolution of the result will ultimately depend on the timebase frequency. Because the timestamp in the VDSO datapage (stamp_xsec, the real time corresponding to the timebase count in tb_orig_stamp) is in units of 2^-20 seconds, it doesn't have sufficient resolution for computing a result with nanosecond resolution. Therefore this adds a copy of xtime to the VDSO datapage and updates it in update_gtod() along with the other time-related fields. Signed-off-by: Paul Mackerras --- Reading git-diff-tree failed