c86d640471
Signed-off-by: Liu Chao <liuchao173@huawei.com> (cherry picked from commit c0c3b00182474729dd198a39b6d05442ed9c0e62)
80 lines
2.9 KiB
Diff
80 lines
2.9 KiB
Diff
From 6418b8c1fbcfdcda4cad8efacccceb7bcdbb1de9 Mon Sep 17 00:00:00 2001
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From: Jim Warner <james.warner@comcast.net>
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Date: Wed, 20 Mar 2024 00:00:00 -0500
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Subject: [PATCH] library: address remaining cpu distortions, <stat> api
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When the potential cpu distortion was addressed in the
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commit referenced below, the revision did not quite go
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far enough. This was revealed in the merge plus issue
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posts also shown. Thus a need for this final solution.
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[ and now that all the stat_jifs fields are verified ]
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[ that TICsetH macro need not check for distortions. ]
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Reference(s):
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https://gitlab.com/procps-ng/procps/-/merge_requests/223
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https://gitlab.com/procps-ng/procps/-/issues/321
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. Mar, 2017 - cpu distorions relocated/improved
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commit 253ac7f709412a8699767bd70faeaf98e19614f0
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Discovered-by: Chao Liu SuperSix173 <liuchao173@huawei.com>
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Signed-off-by: Jim Warner <james.warner@comcast.net>
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---
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library/stat.c | 24 +++++++++++++++---------
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1 file changed, 15 insertions(+), 9 deletions(-)
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diff --git a/library/stat.c b/library/stat.c
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index c37e9b54..b04fe0a5 100644
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--- a/library/stat.c
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+++ b/library/stat.c
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@@ -182,9 +182,10 @@ struct stat_info {
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#define SYS_set(e,t,x) setDECL(e) { \
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(void)T; R->result. t = S->new. x; }
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// delta assignment
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+// ( thanks to 'stat_derive_unique', this macro no longer needs to )
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+// ( protect against a negative value when a cpu is brought online )
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#define TICsetH(e,t,x) setDECL(e) { \
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- (void)S; R->result. t = ( T->new. x - T->old. x ); \
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- if (R->result. t < 0) R->result. t = 0; }
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+ (void)S; R->result. t = ( T->new. x - T->old. x ); }
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#define SYSsetH(e,t,x) setDECL(e) { \
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(void)T; R->result. t = ( S->new. x - S->old. x ); }
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@@ -555,6 +556,9 @@ wrap_up:
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static inline void stat_derive_unique (
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struct hist_tic *this)
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{
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+ unsigned long long *new, *old;
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+ int i;
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+
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/* note: we calculate these derived values in a manner consistent with
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the calculations for cgroup accounting, as nearly as possible
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( see linux sources: ./kernel/cgroup/rstat.c, root_cgroup_cputime ) */
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@@ -576,13 +580,15 @@ static inline void stat_derive_unique (
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this->new.xbsy
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= this->new.xtot - this->new.xidl;
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- // don't distort deltas when cpus are taken offline or brought online
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- if (this->new.xusr < this->old.xusr
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- || (this->new.xsys < this->old.xsys)
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- || (this->new.xidl < this->old.xidl)
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- || (this->new.xbsy < this->old.xbsy)
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- || (this->new.xtot < this->old.xtot))
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- memcpy(&this->old, &this->new, sizeof(struct stat_jifs));
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+ // don't distort results when cpus are brought back online
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+ new = (unsigned long long *)&this->new;
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+ old = (unsigned long long *)&this->old;
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+ for (i = 0; i < sizeof(struct stat_jifs) / sizeof(unsigned long long); i++) {
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+ if (*(new++) < *(old++)) {
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+ memcpy(&this->old, &this->new, sizeof(struct stat_jifs));
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+ break;
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+ }
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+ }
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} // end: stat_derive_unique
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--
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2.33.0
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