From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============0986713686302278736==" MIME-Version: 1.0 From: =?utf-8?q?=E5=82=A8_=3Ccjj25233_at_163=2Ecom=3E?= Subject: [SPDK] A issue about maximums of write latency when we access the same block consecutively. Date: Tue, 01 Aug 2017 15:58:33 +0800 Message-ID: <3c980ad5.7f88.15d9ccdb438.Coremail.cjj25233@163.com> List-ID: To: spdk@lists.01.org --===============0986713686302278736== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Hi, all Recently, we use a demo to obverse the latency. We find that when we access the same block consecutively, the occurrence of= maximum latencies will become more frequent. = Additionally, they can reach even 2-3 ms and present a periodical change. = Why? (1) For the same block, the latency of the first accessing is about 10-12 = =CE=BCs while the second, third = and the forth accessing can reach 700-900 =CE=BCs even 2-3 ms? = I want to know the reason why the operation difference between the fir= st accessing and the others exists. (2) Why the maximums of 2-3 ms have a periodical change? Best wishes, Jiajia Chu = = =20 --===============0986713686302278736== Content-Type: text/html MIME-Version: 1.0 Content-Transfer-Encoding: base64 Content-Disposition: attachment; filename="attachment.html" PGRpdiBzdHlsZT0ibGluZS1oZWlnaHQ6MS43O2NvbG9yOiMwMDAwMDA7Zm9udC1zaXplOjE0cHg7 Zm9udC1mYW1pbHk6QXJpYWwiPjxkaXYgc3R5bGU9ImxpbmUtaGVpZ2h0OjEuNztjb2xvcjojMDAw MDAwO2ZvbnQtc2l6ZToxNHB4O2ZvbnQtZmFtaWx5OkFyaWFsIj48ZGl2IHN0eWxlPSJsaW5lLWhl aWdodDoxLjc7Y29sb3I6IzAwMDAwMDtmb250LXNpemU6MTRweDtmb250LWZhbWlseTpBcmlhbCI+ PGRpdiBzdHlsZT0ibGluZS1oZWlnaHQ6MS43O2NvbG9yOiMwMDAwMDA7Zm9udC1zaXplOjE0cHg7 Zm9udC1mYW1pbHk6QXJpYWwiPjxkaXY+SGksIGFsbDwvZGl2PjxkaXY+UmVjZW50bHksIHdlIHVz ZSBhIGRlbW8gdG8gb2J2ZXJzZSB0aGUgbGF0ZW5jeS48L2Rpdj48ZGl2PldlIGZpbmQgdGhhdCB3 aGVuIHdlIGFjY2VzcyB0aGUgc2FtZSBibG9jayBjb25zZWN1dGl2ZWx5LCB0aGUgb2NjdXJyZW5j ZSBvZiBtYXhpbXVtIGxhdGVuY2llcyB3aWxsIGJlY29tZSBtb3JlIGZyZXF1ZW50LiZuYnNwOzwv ZGl2PjxkaXY+QWRkaXRpb25hbGx5LCAmbmJzcDt0aGV5IGNhbiByZWFjaCBldmVuIDItMyBtcyBh 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