On 11/02/2011 09:51 AM, Eugene Kirpichov wrote:
Hi Claude,
I suspected that the issue could be about unsafe foreign imports - all imports in the cairo bindings are "safe". I compiled myself a version of cairo bindings with the "rectangle" and "fill" functions marked as unsafe.
Unfortunately that didn't help the case at all, even though the core changed FFI calls from "__pkg_ccall_GC" to "__pkg_ccall". The performance stayed the same; the overhead is elsewhere.
doing a ltrace, i think the reason is pretty obvious, there's a lot of GMP calls: __gmpz_init(0x7f5043171730, 1, 0x7f5043171750, 0x7f5043171740, 0x7f50431d2508) = 0x7f50431d2530 __gmpz_mul(0x7f5043171730, 0x7f5043171750, 0x7f5043171740, 0x7f50431d2538, 0x7f50431d2508) = 1 __gmpz_init(0x7f5043171728, 1, 0x7f5043171748, 0x7f5043171738, 0x7f50431d2538) = 0x7f50431d2568 __gmpz_mul(0x7f5043171728, 0x7f5043171748, 0x7f5043171738, 0x7f50431d2570, 0x7f50431d2538) = 1 __gmpn_gcd_1(0x7f50431d2580, 1, 1, 1, 1) = 1 <repeated thousand of time> before each call cairo calls. just to make sure, the C version doesn't exhibit this behavior. -- Vincent