Date: Sat, 15 Apr 1995 14:04:59 -0700 From: Bruce Evans <bde> To: CVS-commiters, cvs-sys Subject: cvs commit: src/sys/kern tty.c Message-ID: <199504152104.OAA00998@freefall.cdrom.com>
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bde 95/04/15 14:04:59 Modified: sys/kern tty.c Log: Speed up ttnread() in the !(ICANON | ISIG) case by copying to user space through a temporary buffer instead of one character at a time. The old method takes about 6 usec/char on a 486DX2/66. This is larger than than the combined interrupt and PIO overhead for a 16550! This change was first implemented in 1.1.5. It was rewritten for 2.1. The clist access functions allow a simpler implementation at some cost in correctness and speed. There needs to be an ungetc() function to recover from EFAULT, and it wastes time to copy through a temporary buffer. Don't snoop on single characters that weren't read due to EFAULT. Rewrite a snoop comment in my approximation to English. Undo bogus exportation of ttnread().
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