the code logic would touch crc cache is bufferlist::crc32c and invalidate_crc. we call bufferlist::crc32 when sending or receiving message and writing filejournal. I miss something critical? I am agree with you that the benefit from that cache cache is every limit. 2015-11-11 16:25 GMT+08:00 Evgeniy Firsov <Evgeniy.Firsov@xxxxxxxxxxx>: > Rb-tree construction, insertion, which needs memory allocation, mutex > lock, unlock is more CPU expensive then streamlined crc calculation of > sometimes 100 bytes or less. > > On 11/11/15, 12:03 AM, "池信泽" <xmdxcxz@xxxxxxxxx> wrote: > >>Ah, I confuse that why the crc cache logic would exhaust so much cpu. >> >>2015-11-11 15:27 GMT+08:00 Evgeniy Firsov <Evgeniy.Firsov@xxxxxxxxxxx>: >>> Hello, Guys! >>> >>> While running CPU bound 4k block workload, I found that disabling crc >>> cache in the buffer::raw gives around 7% performance improvement. >>> >>> If there is no strong use case which benefit from that cache, we would >>> remove it entirely, otherwise conditionally enable it based on the >>>object >>> size. >>> >>> ‹ >>> Evgeniy >>> >>> -- >>> To unsubscribe from this list: send the line "unsubscribe ceph-devel" in >>> the body of a message to majordomo@xxxxxxxxxxxxxxx >>> More majordomo info at http://vger.kernel.org/majordomo-info.html >> >> >> >>-- >>Regards, >>xinze > -- Regards, xinze -- To unsubscribe from this list: send the line "unsubscribe ceph-devel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
