38 lines
1.4 KiB
Diff
38 lines
1.4 KiB
Diff
commit b22be68453b2497e86cbd273b9cd56fadc5859e3
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Author: Ying Lv <lvying6@huawei.com>
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Date: Wed May 15 11:15:42 2019 +0800
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fix rasdaemon high CPU usage when part of CPUs offline
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When we set part of CPU core offline, such as by setting the kernel cmdline
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maxcpus = N(N is less than the total number of system CPU cores).
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And then, we will observe that the CPU usage of some rasdaemon threads
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is very close to 100.
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This is because when part of CPU offline, poll in read_ras_event_all_cpus func
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will fallback to pthread way.
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Offlined CPU thread will return negative value when read trace_pipe_raw,
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negative return value will covert to positive value because of 'unsigned size'.
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So code will always go into 'size > 0' branch, and the CPU usage is too high.
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Here, variable size uses int type will go to the right branch.
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Fiexs: eff7c9e0("ras-events: Only use pthreads for collect if poll() not available")
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Reported-by: Zhipeng Xie <xiezhipeng1@huawei.com>
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Signed-off-by: Ying Lv <lvying6@huawei.com>
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Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
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diff --git a/ras-events.c b/ras-events.c
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index 4e7b815..38ebe1e 100644
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--- a/ras-events.c
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+++ b/ras-events.c
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@@ -426,7 +426,7 @@ static int read_ras_event(int fd,
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struct kbuffer *kbuf,
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void *page)
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{
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- unsigned size;
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+ int size;
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unsigned long long time_stamp;
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void *data;
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