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author | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-03-19 20:24:17 -0400 |
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committer | Steven Rostedt (Google) <rostedt@goodmis.org> | 2022-03-24 17:47:44 -0400 |
commit | 627c496632f9c7f3a1aa836847dfa6ee310f0b55 (patch) | |
tree | a7f036d411f94e23b06daba45ca19e3cad3b2810 | |
parent | 476ee517c4625f1f90ceac544d02e9bed0ffc469 (diff) | |
download | libtraceevent-627c496632f9c7f3a1aa836847dfa6ee310f0b55.tar.gz |
libtraceevent: Optimize print format parsing of constants
While debugging another issue, I found that there's no optimization of
operations in the print format for constants. That is, for example, the
sched_switch event has:
(REC->prev_state & ((((0x0000 | 0x0001 | 0x0002 | 0x0004 | 0x0008 | 0x0010 | 0x0020 | 0x0040) + 1) << 1) - 1))
Where it actually calculates the
(0x0000 | 0x0001 | 0x0002 | 0x0004 | 0x0008 | 0x0010 | 0x0020 | 0x0040) + 1) << 1) - 1)
at every event! instead of just testing against 255 (which it is
calculated to).
Add the calculation at the time the event print format is parsed.
Link: https://lore.kernel.org/linux-trace-devel/20220319202417.6f6608d1@rorschach.local.home
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
-rw-r--r-- | src/event-parse.c | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/src/event-parse.c b/src/event-parse.c index f862f49..4dc4743 100644 --- a/src/event-parse.c +++ b/src/event-parse.c @@ -2144,6 +2144,120 @@ static int set_op_prio(struct tep_print_arg *arg) return arg->op.prio; } +static int consolidate_op_arg(struct tep_print_arg *arg) +{ + unsigned long long val, left, right; + int ret = 0; + + if (arg->type != TEP_PRINT_OP) + return 0; + + if (arg->op.left) + ret = consolidate_op_arg(arg->op.left); + if (ret < 0) + return ret; + + if (arg->op.right) + ret = consolidate_op_arg(arg->op.right); + if (ret < 0) + return ret; + + if (!arg->op.left || !arg->op.right) + return 0; + + if (arg->op.left->type != TEP_PRINT_ATOM || + arg->op.right->type != TEP_PRINT_ATOM) + return 0; + + /* Two atoms, we can do the operation now. */ + left = strtoull(arg->op.left->atom.atom, NULL, 0); + right = strtoull(arg->op.right->atom.atom, NULL, 0); + + switch (arg->op.op[0]) { + case '>': + switch (arg->op.op[1]) { + case '>': + val = left >> right; + break; + case '=': + val = left >= right; + break; + default: + val = left > right; + break; + } + break; + case '<': + switch (arg->op.op[1]) { + case '<': + val = left << right; + break; + case '=': + val = left <= right; + break; + default: + val = left < right; + break; + } + break; + case '&': + switch (arg->op.op[1]) { + case '&': + val = left && right; + break; + default: + val = left & right; + break; + } + break; + case '|': + switch (arg->op.op[1]) { + case '|': + val = left || right; + break; + default: + val = left | right; + break; + } + break; + case '-': + val = left - right; + break; + case '+': + val = left + right; + break; + case '*': + val = left * right; + break; + case '^': + val = left ^ right; + break; + case '/': + val = left / right; + break; + case '%': + val = left % right; + break; + case '=': + /* Only '==' is called here */ + val = left == right; + break; + case '!': + /* Only '!=' is called here. */ + val = left != right; + break; + default: + return 0; + } + + free_arg(arg->op.left); + free_arg(arg->op.right); + + arg->type = TEP_PRINT_ATOM; + free(arg->op.op); + return asprintf(&arg->atom.atom, "%lld", val) < 0 ? -1 : 0; +} + /* Note, *tok does not get freed, but will most likely be saved */ static enum tep_event_type process_op(struct tep_event *event, struct tep_print_arg *arg, char **tok) @@ -3506,6 +3620,10 @@ static int event_read_print_args(struct tep_event *event, struct tep_print_arg * if (type == TEP_EVENT_OP) { type = process_op(event, arg, &token); free_token(token); + + if (consolidate_op_arg(arg) < 0) + type = TEP_EVENT_ERROR; + if (type == TEP_EVENT_ERROR) { *list = NULL; free_arg(arg); |