| Message ID | 20191021094730.57332-1-wqu@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] tools/lib/traceevent, perf tools: Handle %pU format correctly | expand |
On Mon, 21 Oct 2019 17:47:30 +0800 Qu Wenruo <wqu@suse.com> wrote: > +static void print_uuid_arg(struct trace_seq *s, void *data, int size, > + struct tep_event *event, struct tep_print_arg *arg) > +{ > + unsigned char *buf; > + int i; > + > + if (arg->type != TEP_PRINT_FIELD) { > + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type); > + return; > + } > + > + if (!arg->field.field) { > + arg->field.field = tep_find_any_field(event, arg->field.name); > + if (!arg->field.field) { > + do_warning("%s: field %s not found", > + __func__, arg->field.name); > + return; > + } > + } > + if (arg->field.field->size < 16) { > + trace_seq_printf(s, "INVALID UUID: size have %u expect 16", > + arg->field.field->size); > + return; > + } > + buf = data + arg->field.field->offset; > + > + for (i = 0; i < 8; i++) { > + trace_seq_printf(s, "%02x", buf[2 * i]); > + trace_seq_printf(s, "%02x", buf[2 * i + 1]); > + if (1 <= i && i <= 4) I'm fine with this patch except for one nit. The above is hard to read (in my opinion), and I absolutely hate the "constant" compare to "variable" notation. Please change the above to: if (i >= 1 && i <= 4) Thanks, -- Steve > + trace_seq_putc(s, '-'); > + } > +} > +
On 2019/10/21 下午9:56, Steven Rostedt wrote: > On Mon, 21 Oct 2019 17:47:30 +0800 > Qu Wenruo <wqu@suse.com> wrote: > >> +static void print_uuid_arg(struct trace_seq *s, void *data, int size, >> + struct tep_event *event, struct tep_print_arg *arg) >> +{ >> + unsigned char *buf; >> + int i; >> + >> + if (arg->type != TEP_PRINT_FIELD) { >> + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type); >> + return; >> + } >> + >> + if (!arg->field.field) { >> + arg->field.field = tep_find_any_field(event, arg->field.name); >> + if (!arg->field.field) { >> + do_warning("%s: field %s not found", >> + __func__, arg->field.name); >> + return; >> + } >> + } >> + if (arg->field.field->size < 16) { >> + trace_seq_printf(s, "INVALID UUID: size have %u expect 16", >> + arg->field.field->size); >> + return; >> + } >> + buf = data + arg->field.field->offset; >> + >> + for (i = 0; i < 8; i++) { >> + trace_seq_printf(s, "%02x", buf[2 * i]); >> + trace_seq_printf(s, "%02x", buf[2 * i + 1]); >> + if (1 <= i && i <= 4) > > I'm fine with this patch except for one nit. The above is hard to read > (in my opinion), and I absolutely hate the "constant" compare to > "variable" notation. Please change the above to: > > if (i >= 1 && i <= 4) Isn't this ( 1 <= i && i <= 4 ) easier to find out the lower and upper boundary? only two numbers, both at the end of the expression. I feel that ( i >= 1 && i <= 4 ) easier to write, but takes me extra half second to read, thus I changed to the current one. Thanks, Qu > > Thanks, > > -- Steve > >> + trace_seq_putc(s, '-'); >> + } >> +} >> +
On Mon, 21 Oct 2019 22:03:21 +0800 Qu Wenruo <quwenruo.btrfs@gmx.com> wrote: > On 2019/10/21 下午9:56, Steven Rostedt wrote: > > On Mon, 21 Oct 2019 17:47:30 +0800 > > Qu Wenruo <wqu@suse.com> wrote: > > > >> +static void print_uuid_arg(struct trace_seq *s, void *data, int size, > >> + struct tep_event *event, struct tep_print_arg *arg) > >> +{ > >> + unsigned char *buf; > >> + int i; > >> + > >> + if (arg->type != TEP_PRINT_FIELD) { > >> + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type); > >> + return; > >> + } > >> + > >> + if (!arg->field.field) { > >> + arg->field.field = tep_find_any_field(event, arg->field.name); > >> + if (!arg->field.field) { > >> + do_warning("%s: field %s not found", > >> + __func__, arg->field.name); > >> + return; > >> + } > >> + } > >> + if (arg->field.field->size < 16) { > >> + trace_seq_printf(s, "INVALID UUID: size have %u expect 16", > >> + arg->field.field->size); > >> + return; > >> + } > >> + buf = data + arg->field.field->offset; > >> + > >> + for (i = 0; i < 8; i++) { > >> + trace_seq_printf(s, "%02x", buf[2 * i]); > >> + trace_seq_printf(s, "%02x", buf[2 * i + 1]); > >> + if (1 <= i && i <= 4) > > > > I'm fine with this patch except for one nit. The above is hard to read > > (in my opinion), and I absolutely hate the "constant" compare to > > "variable" notation. Please change the above to: > > > > if (i >= 1 && i <= 4) > > Isn't this ( 1 <= i && i <= 4 ) easier to find out the lower and upper > boundary? only two numbers, both at the end of the expression. I don't read it like that. > > I feel that ( i >= 1 && i <= 4 ) easier to write, but takes me extra > half second to read, thus I changed to the current one. How do you read it in English? "If one is less than or equal to i and i is less than or equal to four." Or "If i is greater than or equal to one and i is less than or equal to four." ? I read it the second way, and I believe most English speakers read it that way too. It took me a minute or two to understand the original method, because my mind likes to take a variable and keep it on the same side of the comparison, and the variable should always be first. -- Steve
On 2019/10/21 下午10:24, Steven Rostedt wrote: > On Mon, 21 Oct 2019 22:03:21 +0800 > Qu Wenruo <quwenruo.btrfs@gmx.com> wrote: > >> On 2019/10/21 下午9:56, Steven Rostedt wrote: >>> On Mon, 21 Oct 2019 17:47:30 +0800 >>> Qu Wenruo <wqu@suse.com> wrote: >>> >>>> +static void print_uuid_arg(struct trace_seq *s, void *data, int size, >>>> + struct tep_event *event, struct tep_print_arg *arg) >>>> +{ >>>> + unsigned char *buf; >>>> + int i; >>>> + >>>> + if (arg->type != TEP_PRINT_FIELD) { >>>> + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type); >>>> + return; >>>> + } >>>> + >>>> + if (!arg->field.field) { >>>> + arg->field.field = tep_find_any_field(event, arg->field.name); >>>> + if (!arg->field.field) { >>>> + do_warning("%s: field %s not found", >>>> + __func__, arg->field.name); >>>> + return; >>>> + } >>>> + } >>>> + if (arg->field.field->size < 16) { >>>> + trace_seq_printf(s, "INVALID UUID: size have %u expect 16", >>>> + arg->field.field->size); >>>> + return; >>>> + } >>>> + buf = data + arg->field.field->offset; >>>> + >>>> + for (i = 0; i < 8; i++) { >>>> + trace_seq_printf(s, "%02x", buf[2 * i]); >>>> + trace_seq_printf(s, "%02x", buf[2 * i + 1]); >>>> + if (1 <= i && i <= 4) >>> >>> I'm fine with this patch except for one nit. The above is hard to read >>> (in my opinion), and I absolutely hate the "constant" compare to >>> "variable" notation. Please change the above to: >>> >>> if (i >= 1 && i <= 4) >> >> Isn't this ( 1 <= i && i <= 4 ) easier to find out the lower and upper >> boundary? only two numbers, both at the end of the expression. > > I don't read it like that. > >> >> I feel that ( i >= 1 && i <= 4 ) easier to write, but takes me extra >> half second to read, thus I changed to the current one. > > How do you read it in English? How about mathematics interval? i in [1, 4]. It looks way easier and simpler no matter what language you speak. Thanks, Qu > > "If one is less than or equal to i and i is less than or equal to > four." > > Or > > "If i is greater than or equal to one and i is less than or equal to > four." > > ? > > I read it the second way, and I believe most English speakers read it > that way too. > > It took me a minute or two to understand the original method, because > my mind likes to take a variable and keep it on the same side of the > comparison, and the variable should always be first. > > -- Steve > >
On Mon, 21 Oct 2019 22:30:37 +0800 Qu Wenruo <quwenruo.btrfs@gmx.com> wrote: > > How do you read it in English? > > How about mathematics interval? > > i in [1, 4]. > > It looks way easier and simpler no matter what language you speak. But C doesn't accept that syntax ;-) -- Steve
diff --git a/tools/lib/traceevent/event-parse.c b/tools/lib/traceevent/event-parse.c index d948475585ce..a71f4a86b6ca 100644 --- a/tools/lib/traceevent/event-parse.c +++ b/tools/lib/traceevent/event-parse.c @@ -18,6 +18,7 @@ #include <errno.h> #include <stdint.h> #include <limits.h> +#include <linux/uuid.h> #include <linux/time64.h> #include <netinet/in.h> @@ -4508,6 +4509,40 @@ get_bprint_format(void *data, int size __maybe_unused, return format; } +static void print_uuid_arg(struct trace_seq *s, void *data, int size, + struct tep_event *event, struct tep_print_arg *arg) +{ + unsigned char *buf; + int i; + + if (arg->type != TEP_PRINT_FIELD) { + trace_seq_printf(s, "ARG TYPE NOT FIELID but %d", arg->type); + return; + } + + if (!arg->field.field) { + arg->field.field = tep_find_any_field(event, arg->field.name); + if (!arg->field.field) { + do_warning("%s: field %s not found", + __func__, arg->field.name); + return; + } + } + if (arg->field.field->size < 16) { + trace_seq_printf(s, "INVALID UUID: size have %u expect 16", + arg->field.field->size); + return; + } + buf = data + arg->field.field->offset; + + for (i = 0; i < 8; i++) { + trace_seq_printf(s, "%02x", buf[2 * i]); + trace_seq_printf(s, "%02x", buf[2 * i + 1]); + if (1 <= i && i <= 4) + trace_seq_putc(s, '-'); + } +} + static void print_mac_arg(struct trace_seq *s, int mac, void *data, int size, struct tep_event *event, struct tep_print_arg *arg) { @@ -5074,6 +5109,22 @@ static void pretty_print(struct trace_seq *s, void *data, int size, struct tep_e arg = arg->next; break; } + } else if (*ptr == 'U') { + /* + * %pU has several finetunings variants + * like %pUb and %pUL. + * Here we ignore them, default to + * byte-order no endian, lower case + * letters. + */ + if (isalpha(ptr[1])) + ptr += 2; + else + ptr++; + + print_uuid_arg(s, data, size, event, arg); + arg = arg->next; + break; } /* fall through */
[BUG] For btrfs related events, there is a field for fsid, but perf never parse it correctly. # perf trace -e btrfs:qgroup_meta_convert xfs_io -f -c "pwrite 0 4k" \ /mnt/btrfs/file1 0.000 xfs_io/77915 btrfs:qgroup_meta_reserve:(nil)U: refroot=5(FS_TREE) type=0x0 diff=2 ^^^^^^ Not a correct UUID ... [CAUSE] The pretty_print() function doesn't handle the %pU format correctly. In fact it doesn't handle %pU as uuid at all. [FIX] Add a new function, print_uuid_arg(), to handle %pU correctly. Now perf trace can at least print fsid correctly: 0.000 xfs_io/79619 btrfs:qgroup_meta_reserve:23ad1511-dd83-47d4-a79c-e96625a15a6e refroot=5(FS_TREE) type=0x0 diff=2 Signed-off-by: Qu Wenruo <wqu@suse.com> --- Changelog: v2: - Use more comment explaining the finetunings we skipped for %pU* - Extra check for the field before reading the data - Use more elegant way to output uuid string v3: - Use a even more elegant way to output uuid string --- tools/lib/traceevent/event-parse.c | 51 ++++++++++++++++++++++++++++++ 1 file changed, 51 insertions(+)