AWARE SYSTEMS
TIFF and LibTiff Mail List Archive

Thread

2017.11.20 17:04 "[Tiff] TIFF tag and compression registration", by Kemp Watson
2017.11.20 17:34 "Re: [Tiff] TIFF tag and compression registration", by Bob Friesenhahn
2017.11.20 21:01 "Re: [Tiff] TIFF tag and compression registration", by Kemp Watson
2018.01.16 20:08 "Re: [Tiff] Strategies for multi-core speedups", by
2018.01.16 00:15 "Re: [Tiff] Strategies for multi-core speedups", by Bob Friesenhahn
2018.01.15 21:41 "Re: [Tiff] Strategies for multi-core speedups", by Larry Gritz
2018.01.15 19:17 "[Tiff] Strategies for multi-core speedups", by Larry Gritz
2018.01.15 20:23 "Re: [Tiff] Strategies for multi-core speedups", by Bob Friesenhahn
2018.01.15 22:02 "Re: [Tiff] Strategies for multi-core speedups", by Olivier Paquet
2018.01.15 22:47 "Re: [Tiff] Strategies for multi-core speedups", by Craig Bruce
2018.01.15 22:38 "Re: [Tiff] Strategies for multi-core speedups", by Craig Bruce
2018.01.15 22:43 "Re: [Tiff] Strategies for multi-core speedups", by scott ribe
2018.01.15 21:46 "Re: [Tiff] Strategies for multi-core speedups", by scott ribe
2018.01.15 21:51 "Re: [Tiff] Strategies for multi-core speedups", by Larry Gritz
2018.01.16 01:09 "Re: [Tiff] Strategies for multi-core speedups", by Craig Bruce
2018.01.16 18:36 "Re: [Tiff] Strategies for multi-core speedups", by
2018.01.15 23:29 "Re: [Tiff] Strategies for multi-core speedups", by Larry Gritz
2018.01.16 00:24 "Re: [Tiff] Strategies for multi-core speedups", by Bob Friesenhahn
2018.01.16 00:43 "Re: [Tiff] Strategies for multi-core speedups", by Paul Hemmer
2018.01.16 00:58 "Re: [Tiff] Strategies for multi-core speedups", by scott ribe
2018.01.16 07:31 "Re: [Tiff] Strategies for multi-core speedups", by Paavo Helde
2018.01.17 02:00 "Re: [Tiff] Strategies for multi-core speedups", by Larry Gritz
2018.01.24 00:33 "Re: [Tiff] Strategies for multi-core speedups", by Larry Gritz
2018.01.16 18:48 "Re: [Tiff] Strategies for multi-core speedups", by scott ribe
2018.01.16 19:01 "Re: [Tiff] Strategies for multi-core speedups", by Kemp Watson
2018.01.16 19:17 "Re: [Tiff] Strategies for multi-core speedups", by
2018.01.16 19:34 "Re: [Tiff] Strategies for multi-core speedups", by Paavo Helde
2018.01.16 19:52 "Re: [Tiff] Strategies for multi-core speedups", by Kemp Watson
2018.01.16 19:57 "Re: [Tiff] Strategies for multi-core speedups", by
2018.01.16 20:18 "Re: [Tiff] Strategies for multi-core speedups", by Kemp Watson
2018.01.16 20:20 "Re: [Tiff] Strategies for multi-core speedups", by Kemp Watson
2018.01.16 20:23 "Re: [Tiff] Strategies for multi-core speedups", by

2018.01.16 00:43 "Re: [Tiff] Strategies for multi-core speedups", by Paul Hemmer

Very interesting to read this discussion!

> On Jan 15, 2018, at 7:30 PM, Bob Friesenhahn <bfriesen@simple.dallas.tx.us> wrote:

>
>> On Mon, 15 Jan 2018, Larry Gritz wrote:
>>

There is no mystery here -- the I/O itself is still serialized, so if it's only 10% of the total runtime, say, even perfectly linear thread scaling and an unlimited number of cores without any lock contention will experience a maximum of 10x improvement. Amdahl's Law and all that. That effect alone adequately explains my lack of thread scalability beyond 8 or so cores, for this application.

The I/O is not necessarily serialized. When using mmap, pread/pwrite, or asynchronous I/O, the I/O can also benefit from multi-threading given that the underlying storage is a multi-disk array or SSDs using PCIe NVMe (capable of up to 1024 simultaneous I/Os).

Amdahl's Law still applies. :-)

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