Hi, Thanks for the reply.
On 16/06/15 13:09, Andy Polyakov wrote: >> >> With some experimentation, it turns out that if I *stop* using the >> crypto/bn/asm/bn/armv4-mont.pl generated asm "optimised" version, the time >> for >> a simplish test to establish and close a simple SSL connection went from 28 >> seconds to 18. (It's quite a slow target at any time). >> >> In other words, this "optimised" version has slowed things down dramatically. >> Has anyone queried the value of the asm of armv4-mont.pl any time in the last >> few years? > > Yes, of course. For reference, here are speed rsa2048 dsa2048 results > from Cortex-A8. Numbers are operations per second, so that higher is better. > > Without armv4-mont.pl: > > sign verify sign/s verify/s > rsa 2048 bits 0.052684s 0.001421s 19.0 703.5 > dsa 2048 bits 0.014576s 0.017526s 68.6 57.1 > > With armv4-mont.pl but without NEON (ARM SIMD extension): > > rsa 2048 bits 0.039255s 0.001140s 25.5 877.3 > dsa 2048 bits 0.011630s 0.013900s 86.0 71.9 Wow, I get very different results on my ARM9 target. Without armv4-mont.pl: sign verify sign/s verify/s rsa 2048 bits 2.567500s 0.072826s 0.4 13.7 dsa 2048 bits 0.722857s 0.865833s 1.4 1.2 With armv4-mont.pl: sign verify sign/s verify/s rsa 2048 bits 3.433333s 0.104896s 0.3 9.5 dsa 2048 bits 1.058000s 1.253750s 0.9 0.8 What's more, I dug out a Cortex-A9 target (Atmel CycloneV board, operating with single core only) and got this without armv4-mont.pl: sign verify sign/s verify/s rsa 2048 bits 0.127342s 0.003628s 7.9 275.6 dsa 2048 bits 0.035971s 0.042778s 27.8 23.4 and this with armv4-mont.pl: sign verify sign/s verify/s rsa 2048 bits 0.172931s 0.005222s 5.8 191.5 dsa 2048 bits 0.052565s 0.061350s 19.0 16.3 As you can see, in both cases using armv4-mont.pl makes it 30% slower. So whatever is going on, it isn't down to the CPU. I think there must be something else going on. I'll get back to you. Jifl -- eCosCentric Limited http://www.eCosCentric.com/ The eCos experts Barnwell House, Barnwell Drive, Cambridge, UK. Tel: +44 1223 245571 Registered in England and Wales: Reg No 4422071. ------["Si fractum non sit, noli id reficere"]------ Opinions==mine _______________________________________________ openssl-dev mailing list To unsubscribe: https://mta.openssl.org/mailman/listinfo/openssl-dev