From: Paul Mackerras Date: Tue, 26 May 2009 06:27:59 +0000 (+1000) Subject: perf_counter: powerpc: Implement interrupt throttling X-Git-Tag: v2.6.31-rc1~383^2~221 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8a7b8cb91f26a671f22cedc7fd54508667f2d9b9;p=pandora-kernel.git perf_counter: powerpc: Implement interrupt throttling This implements interrupt throttling on powerpc. Since we don't have individual count enable/disable or interrupt enable/disable controls per counter, this simply sets the hardware counter to 0, meaning that it will not interrupt again until it has counted 2^31 counts, which will take at least 2^30 cycles assuming a maximum of 2 counts per cycle. Also, we set counter->hw.period_left to the maximum possible value (2^63 - 1), so we won't report overflows for this counter for the forseeable future. The unthrottle operation restores counter->hw.period_left and the hardware counter so that we will once again report a counter overflow after counter->hw.irq_period counts. [ Impact: new perfcounters robustness feature on PowerPC ] Signed-off-by: Paul Mackerras Cc: Peter Zijlstra Cc: Corey Ashford LKML-Reference: <18971.35823.643362.446774@cargo.ozlabs.ibm.com> Signed-off-by: Ingo Molnar --- Reading git-diff-tree failed