IW15 64bit deployment

[mbtaylor1982]

That's a good info indeed, however AFAIK, only zlib decompression uses optimized SSE 4.2 CRC32. AVX and AVX2 are not used at all. It might be still some instruction not supported by the processor.
BTW, gzip decompression is not used by IntraWeb. Only compression.

It is something questionable that people are using very old processors in servers supposed to run web applications, though. Core i3, i5 and i7 from 2008 already supported SSE 4.2 instructions. Trying to make a brand new IW application run in a 486 DX2/66 MHz doesn't make any sense to me

All I can tell you is that an Intraweb x64 application built with XE4 Using the CloudFlare Zlib will raise an illegal instruction error when starting up on on the processors i mentioned. 

I've included the CPU-Z screen shots here to show what the difference is in supported instruction sets, and as you can see the difference in instruction set is (AES, AVX, AVX2, FMA3, TSX)

   

   

   

Below is a list of some of the improvements in the Cloud Flare fork of zlib

* uint64_t as the standard type - the default fork used 16-bit types.
* Using an improved hash function - we use the iSCSI CRC32 function as the hash function in our zlib. This specific function is implemented as a hardware instruction on Intel processors. It has very fast performance and better collision properties.
* Search for matches of at least 4 bytes, instead the 3 bytes the format suggests. This leads to fewer hash collisions, and less effort wasted on insignificant matches. It also improves the compression rate a little bit for the majority of cases (but not all).
* Using SIMD instructions for window rolling.
* Using the hardware carry-less multiplication instruction PLCMULQDQ for the CRC32 checksum.
* Optimized longest-match function. This is the most performance demanding function in the library. It is responsible for finding the (length, distance) matches in the current window.

As the AVX and AVX2 are SIMD instructions i think they may be using them somewhere. as the I7 950 and Xeon X5550 both support SSE4.2 but wont run the Cloud Flare code.

I agree with you that servers should be running recent processors and hardware, however we can't always dictate when our customers will invest in new servers. therefore it is important to us that we can deploy our Intraweb apps on slightly older platforms. 

I don't think its unreasonable to expect it to run on an Intel Xeon X5550, do you?

Maybe looking at integrating zlib-ng would be a better solution once it has a stable release, as it may be faster than the cloud flare implementation and it contains fallback code if the advanced instruction sets are not available.

EDIT: Having taken a closer look at the Cloud Flare source, I suspect that the Cloud Flare obj files included with Intraweb where complied with the HAS_AVX flag so the OBJ file emitted by GCC contains AVX instructions...