[U-Boot] [PATCH] nvedit: speed up printing of environment

The printing code would check the same environment byte multiple times and write to the console one byte at a time. For some devices (such as the Blackfin JTAG console which operates in 8 bytes at a time), this is pretty damned slow. So create a small 16 byte buffer to fill up and send to puts as needed. In the process, unify the different print functions, shrink the resulting code (source and compiled), and avoid excess env reads as those too can be somewhat expensive depending on the board.
Signed-off-by: Mike Frysinger vapier@gentoo.org --- common/cmd_nvedit.c | 94 ++++++++++++++++++++++++++++++--------------------- 1 files changed, 55 insertions(+), 39 deletions(-)
diff --git a/common/cmd_nvedit.c b/common/cmd_nvedit.c index 95eebb5..a983de4 100644 --- a/common/cmd_nvedit.c +++ b/common/cmd_nvedit.c @@ -85,56 +85,72 @@ int get_env_id (void) * Command interface: print one or all environment variables */
-int do_printenv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +/* + * state 0: finish printing this string and return (matched!) + * state 1: no matching to be done; print everything + * state 2: continue searching for matched name + */ +static int printenv(char *name, int state) { - int i, j, k, nxt; - int rcode = 0; - - if (argc == 1) { /* Print all env variables */ - for (i=0; env_get_char(i) != '\0'; i=nxt+1) { - for (nxt=i; env_get_char(nxt) != '\0'; ++nxt) - ; - for (k=i; k<nxt; ++k) - putc(env_get_char(k)); - putc ('\n'); - - if (ctrlc()) { - puts ("\n ** Abort\n"); - return 1; + int i, j; + char c, buf[17]; + + i = 0; + buf[16] = '\0'; + + while (state && env_get_char(i) != '\0') { + if (state == 2 && envmatch((uchar *)name, i) >= 0) + state = 0; + + j = 0; + do { + buf[j++] = c = env_get_char(i++); + if (j == sizeof(buf) - 1) { + if (state <= 1) + puts(buf); + j = 0; } - } + } while (c != '\0');
- printf("\nEnvironment size: %d/%ld bytes\n", - i, (ulong)ENV_SIZE); + if (state <= 1) { + if (j) + puts(buf); + putc('\n'); + }
- return 0; + if (ctrlc()) + return -1; }
- for (i=1; i<argc; ++i) { /* print single env variables */ - char *name = argv[i]; + if (state == 0) + i = 0; + return i; +}
- k = -1; +int do_printenv (cmd_tbl_t *cmdtp, int flag, int argc, char *argv[]) +{ + int i; + int rcode = 0;
- for (j=0; env_get_char(j) != '\0'; j=nxt+1) { + if (argc == 1) { + /* print all env vars */ + rcode = printenv(NULL, 1); + if (rcode < 0) + return 1; + printf("\nEnvironment size: %d/%ld bytes\n", + rcode, (ulong)ENV_SIZE); + return 0; + }
- for (nxt=j; env_get_char(nxt) != '\0'; ++nxt) - ; - k = envmatch((uchar *)name, j); - if (k < 0) { - continue; - } - puts (name); - putc ('='); - while (k < nxt) - putc(env_get_char(k++)); - putc ('\n'); - break; - } - if (k < 0) { - printf ("## Error: "%s" not defined\n", name); - rcode ++; + /* print selected env vars */ + for (i = 1; i < argc; ++i) { + char *name = argv[i]; + if (printenv(name, 2)) { + printf("## Error: "%s" not defined\n", name); + ++rcode; } } + return rcode; }

Dear Mike Frysinger,
In message 1243146379-5699-1-git-send-email-vapier@gentoo.org you wrote:
The printing code would check the same environment byte multiple times and write to the console one byte at a time. For some devices (such as the Blackfin JTAG console which operates in 8 bytes at a time), this is pretty damned slow. So create a small 16 byte buffer to fill up and send to puts as needed. In the process, unify the different print functions, shrink the resulting code (source and compiled), and avoid excess env reads as those too can be somewhat expensive depending on the board.
Signed-off-by: Mike Frysinger vapier@gentoo.org
common/cmd_nvedit.c | 94 ++++++++++++++++++++++++++++++--------------------- 1 files changed, 55 insertions(+), 39 deletions(-)
Applied to next, thanks.
Best regards,
Wolfgang Denk
participants (2)
-
Mike Frysinger
-
Wolfgang Denk