[PATCH] makedumpfile: Add more descriptions of multi-threads feature
ats-kumagai at wm.jp.nec.com
Sat Jul 30 02:49:50 PDT 2016
>On 07/29/16 at 11:34am, Zhou Wenjian wrote:
>> It will have a bad performance if the threads number is larger than
>> the usable cpu number. So we should remind user of it.
>> Signed-off-by: Zhou Wenjian <zhouwj-fnst at cn.fujitsu.com>
>It makes sense to tell people who use option "-num-threads".
>Acked-by: Baoquan He <bhe at redhat.com>
Looks good to me, I'll merge this into v1.6.1.
>> makedumpfile.8 | 2 ++
>> print_info.c | 2 ++
>> 2 files changed, 4 insertions(+)
>> diff --git a/makedumpfile.8 b/makedumpfile.8
>> index 3b6f7e2..f74abea 100644
>> --- a/makedumpfile.8
>> +++ b/makedumpfile.8
>> @@ -376,6 +376,8 @@ the kdump\-compressed format.
>> \fB\-\-num\-threads\fR \fITHREADNUM\fR
>> Using multiple threads to read and compress data of each page in parallel.
>> And it will reduces time for saving \fIDUMPFILE\fR.
>> +Note that if the usable cpu number is less than the thread number, it may
>> +lead to great performance degradation.
>> This feature only supports creating \fIDUMPFILE\fR in kdump\-comressed
>> format from \fIVMCORE\fR in kdump\-compressed format or elf format.
>> diff --git a/print_info.c b/print_info.c
>> index 1a9f70c..2fbfb12 100644
>> --- a/print_info.c
>> +++ b/print_info.c
>> @@ -200,6 +200,8 @@ print_usage(void)
>> MSG(" [--num-threads THREADNUM]:\n");
>> MSG(" Using multiple threads to read and compress data of each page in parallel.\n");
>> MSG(" And it will reduces time for saving DUMPFILE.\n");
>> + MSG(" Note that if the usable cpu number is less than the thread number, it may\n");
>> + MSG(" lead to great performance degradation.\n");
>> MSG(" This feature only supports creating DUMPFILE in kdump-comressed format from\n");
>> MSG(" VMCORE in kdump-compressed format or elf format.\n");
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