From: Boris Ostrovsky Date: Wed, 30 May 2012 08:26:02 +0000 (+0100) Subject: xenpm: Fix reporting of C0 residence times X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~8379 X-Git-Url: https://dgit.raspbian.org/%22http://www.example.com/cgi/%22/%22http:/www.example.com/cgi/%22?a=commitdiff_plain;h=de0e85188ca9e240e774f4598139ba92ee5ce4f8;p=xen.git xenpm: Fix reporting of C0 residence times Idle state residence times as provided by pmstat_get_cx_stat() are not reported precisely since remote core may be in idle state and therefore has not updated its statistics at the time local core collected them. This causes C0 residencies as calculated by xenpm to sometimes become negative. Signed-off-by: Boris Ostrovsky Committed-by: Keir Fraser --- diff --git a/tools/misc/xenpm.c b/tools/misc/xenpm.c index f07a53967f..65876fe370 100644 --- a/tools/misc/xenpm.c +++ b/tools/misc/xenpm.c @@ -351,8 +351,12 @@ static void signal_int_handler(int signo) for ( i = 0; i < max_cpu_nr; i++ ) if ( !get_cxstat_by_cpuid(xc_handle, i, &cxstat_end[i]) ) for ( j = 0; j < cxstat_end[i].nr; j++ ) - sum_cx[i] += cxstat_end[i].residencies[j] - - cxstat_start[i].residencies[j]; + { + int64_t diff = (int64_t)cxstat_end[i].residencies[j] - + (int64_t)cxstat_start[i].residencies[j]; + if ( diff >=0 ) + sum_cx[i] += diff; + } } if ( get_pxstat_by_cpuid(xc_handle, 0, NULL) != -ENODEV ) @@ -379,8 +383,10 @@ static void signal_int_handler(int signo) { for ( j = 0; j < cxstat_end[i].nr; j++ ) { - res = cxstat_end[i].residencies[j] - - cxstat_start[i].residencies[j]; + int64_t diff = (int64_t)cxstat_end[i].residencies[j] - + (int64_t)cxstat_start[i].residencies[j]; + + res = ( diff >= 0 ) ? diff : 0; triggers = cxstat_end[i].triggers[j] - cxstat_start[i].triggers[j]; avg_res = (triggers==0) ? 0: (double)res/triggers/1000000.0;