From mboxrd@z Thu Jan 1 00:00:00 1970 From: Eric Barton Date: Thu, 26 May 2011 14:01:08 +0100 Subject: [Lustre-devel] New test results for "ls -Ul" In-Reply-To: <4DCBA5D4.5010902@whamcloud.com> References: <4DCBA5D4.5010902@whamcloud.com> Message-ID: <012401cc1ba4$fc090da0$f41b28e0$@com> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lustre-devel@lists.lustre.org Nasf, Interesting results. Thank you - especially for graphing the results so thoroughly. I'm attaching them here and cc-ing lustre-devel since these are of general interest. I don't think your conclusion number (1), to say CLIO locking is slowing us down is as obvious from these results as you imply. If you just compare the 1.8 and patched 2.x per-file times and how they scale with #stripes you get this. The gradients of these lines should correspond to the additional time per stripe required to stat each file and I've graphed these times below (ignoring the 0-stripe data for this calculation because I'm just interested in the incremental per-stripe overhead). They show per-stripe overhead for 1.8 well above patched 2.x for the lower stripe counts, but whereas 1.8 gets better with more stripes, patched 2.x gets worse. I'm guessing that at high stripe counts, 1.8 puts many concurrent glimpses on the wire and does it quite efficiently. I'd like to understand better how you control the # of glimpse-aheads you keep on the wire - is it a single fixed number, or a fixed number per OST or some other scheme? In any case, it will be interesting to see measurements at higher stripe counts. Cheers, Eric From: Fan Yong [mailto:yong.fan at whamcloud.com] Sent: 12 May 2011 10:18 AM To: Eric Barton Cc: Bryon Neitzel; Ian Colle; Liang Zhen Subject: New test results for "ls -Ul" I have improved statahead load balance mechanism to distribute statahead load to more CPU units on client. And adjusted AGL according to CLIO lock state machine. After those improvement, 'ls -Ul' can run more fast than old patches, especially on large SMP node. On the other hand, as the increasing the degree of parallelism, the lower network scheduler is becoming performance bottleneck. So I combine my patches together with Liang's SMP patches in the test. client (fat-intel-4, 24 cores) server (client-xxx, 4 OSSes, 8 OSTs on each OSS) b2x_patched my patches + SMP patches my patches b18 original b1_8 share the same server with "b2x_patched" b2x_original original b2_x original b2_x Some notes: 1) Stripe count affects traversing performance much, and the impact is more than linear. Even if with all the patches applied on b2_x, the degree of stripe count impact is still larger than b1_8. It is related with the complex CLIO lock state machine and tedious iteration/repeat operations. It is not easy to make it run as efficiently as b1_8. 2) Patched b2_x is much faster than original b2_x, for traversing 400K * 32-striped directory, it is 100 times or more improved. 3) Patched b2_x is also faster than b1_8, within our test, patched b2_x is at least 4X faster than b1_8, which matches the requirement in ORNL contract. 4) Original b2_x is faster than b1_8 only for small striped cases, not more than 4-striped. For large striped cases, slower than b1_8, which is consistent with ORNL test result. 5) The largest stripe count is 32 in our test. We have not enough resource to test more large striped cases. And I also wonder whether it is worth to test more large striped directory or not. Because how many customers want to use large and full striped directory? means contains 1M * 160-striped items in signal directory. If it is rare case, then wasting lots of time on that is worthless. We need to confirm with ORNL what is the last acceptance test cases and environment, includes: a) stripe count b) item count c) network latency, w/o lnet router, suggest without router. d) OST count on each OSS Cheers, -- Nasf -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/png Size: 64417 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: image/png Size: 57471 bytes Desc: not available URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: result_20110512.xls Type: application/vnd.ms-excel Size: 61952 bytes Desc: not available URL: