On 2/21/24 21:23, Bernhard Reutner-Fischer wrote:
Hi Sukyoung!
please don't top-post
On Mon, 19 Feb 2024 10:22:05 +0000
Matthew Chae <[email protected]> wrote:
Hi Bernhard,
I'm sending new patch and the result of bloatcheck.
For me, this size is reduced to 135 bytes. What do you think?
Well, 135b is better than the initial 360b :)
Can you take a look at these attachments?
I'd love to.
But it doesn't apply, unfortunately:
$ git am -s 0004-Allocate-PID-PPID-space-dynamically-in-top-command.patch
Applying: Allocate PID/PPID space dynamically in top command
error: patch failed: procps/top.c:637
error: procps/top.c: patch does not apply
Patch failed at 0001 Allocate PID/PPID space dynamically in top command
hint: Use 'git am --show-current-patch=diff' to see the failed patch
When you have resolved this problem, run "git am --continue".
If you prefer to skip this patch, run "git am --skip" instead.
To restore the original branch and stop patching, run "git am --abort".
$ git am --abort
$ patch -p1 -i 0004-Allocate-PID-PPID-space-dynamically-in-top-command.patch
patching file procps/top.c
Hunk #1 FAILED at 637.
Hunk #2 FAILED at 696.
Hunk #3 FAILED at 709.
3 out of 3 hunks FAILED -- saving rejects to file procps/top.c.rej
So I'd have to manually fiddle the patch to apply, which i honestly
don't have time for ATM, as much as i love code-golf in general.
It’s very strange. Anyway, I'm sorry for causing you inconvenience.
At least now it shows successful results like below.
git am -s 0005-Allocate-PID-PPID-space-dynamically-in-top-command.patch
Applying: Allocate PID/PPID space dynamically in top command
Plus, the size is reduced more. It shows 115 bytes. You can check this
in the bloatcheck_result file.
Furthermore (and i'm about to update https://busybox.net/developer
accordingly), for legal reasons, we require a Signed-off-by, as
detailed in
https://www.kernel.org/doc/html/latest/process/submitting-patches.html?highlight=sign%20off#sign-your-work-the-developer-s-certificate-of-origin
so please check you legal department (which should be fine for axis)
and mark your contributions accordingly by 'git commit -s ...' iff this
is in line with your legal situation (again, axis legal will most
likely understand what this is about without much further ado, AFAIK).
I already added this in the previous patch. Can you check the
attachment? If I'm missing something, please let me know.
PS:
The function of count_digits() is implemented inside of display_process_list().
To reduce the size, strlen() is not used.
Did you look if manually outlining count_digits() like you did in the
previous version is beneficial?
I don’t think outlining count_digits() is beneficial now. It appears
that, at least until now, there is no use case within BusyBox for
counting the digits of an integer variable. In terms of size as well,
using strlen() and utoa() as in the attached code appears to be more
advantageous. BTW, using make_human_readable_str() in the approach you
recommended does not seem appropriate for calculating the number of
digits. (pid_len = strlen(make_human_readable_str(pid_max,0,0))
If I misunderstood, please let me know.
And, did you check my previous question if it is better to use the
manual buf "painting", perusing in this case pid_len (for the
compile-time constant 6 as it is now) and ppid_len (ditto), and, for
your other patch on top, username_len (for the current compile-time
constant 8)? The loop to determine the max {,p}pid len is not for free
of course, so it's okish if that manifests size-wise.
When large numbers are assigned to PID and PPID, they occupy many
digits, leading to overflow in the PID and PPID columns. Consequently,
it becomes impossible to display the entire data accurately and neatly.
Additionally, a significant portion of the user name may get truncated,
providing very limited information about the user name. By using this
patch, although the loop is not for free, it allows for the very
accurate display of results from the top command. Furthermore, the size
is reduced to an appropriate level(115 bytes), enabling very efficient
results with minimal investment."
Below is an example of how it can be improved.
Before:
PID PPID USER
4876586 4394176 busy
After:
PID PPID USER
4876548 4394517 busybox
PS: 135b is better than the initial suggestion of ~300b, but given
architectures tend to end up with very different codegen per arch and
compilers used, i'm always curious which arch and which compiler
(version) was used to obtain the alleged results. Guess you target
chris with gcc-12-ish?
Stating the target arch usually allows us a rough estimate
about overall impact on other arches.
I’m giving you the arch and compiler information below.
C Compiler: gcc -> gcc-10*
ARCH x86_64
Many thanks in advance and cheers,
Bernhard
Br-Matthew
________________________________
From: Bernhard Reutner-Fischer <[email protected]>
Sent: Thursday, February 15, 2024 9:46 PM
To: Matthew Chae <[email protected]>
Cc: [email protected] <[email protected]>; David Laight <[email protected]>; 'Denys
Vlasenko' <[email protected]>; [email protected] <[email protected]>; Christopher Wong
<[email protected]>
Subject: Re: fix large PID overflow their column in top command
On Wed, 14 Feb 2024 14:05:15 +0000
Matthew Chae <[email protected]> wrote:
Hi Bernhard,
I'm sending new patch and the result of bloatcheck.
Many thanks for the updated patch!
function old new delta
display_process_list 1406 1765 +359
.rodata 99721 99724 +3
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 362/0) Total: 362 bytes
text data bss dec hex filename
1009548 16507 1840 1027895 faf37 busybox_old
1009910 16507 1840 1028257 fb0a1 busybox_unstripped
I think that's too much. For me this gives +293 bytes, still way too much.
Can you please see if it helps to retain the manual formatting of
PID PPID USER?
PS:
procps/top.c: In function ‘display_process_list’:
procps/top.c:664:1: warning: ISO C90 forbids mixed declarations and code
[-Wdeclaration-after-statement]
664 | typedef struct { unsigned quot, rem; } bb_div_t;
| ^~~~~~~
so please move your new #define PID_STR block down to right before
/* what info of the processes is shown */
In
+ int lines = (lines_rem - 1);
please drop the superfluous braces.
It is most likely not smaller to use
pid_len = strlen(make_human_readable_str(pid_max,0,0))
than to introduce this private count_digits(), i fear?
Maybe we could amortize the addition of count_digits by
reusing it elsewhere, as a follow-up.
thanks
Can you review these and give me your thoughts?
Just let me know if you think that the code size needs to be reduced.
Br-Matthew
________________________________
From: Bernhard Reutner-Fischer <[email protected]>
Sent: Tuesday, February 13, 2024 7:16 PM
To: Matthew Chae <[email protected]>
Cc: [email protected] <[email protected]>; David Laight <[email protected]>; 'Denys
Vlasenko' <[email protected]>; [email protected] <[email protected]>; Christopher Wong
<[email protected]>
Subject: Re: fix large PID overflow their column in top command
On Mon, 5 Feb 2024 09:56:20 +0000
Matthew Chae <[email protected]> wrote:
Hi David,
I'm sending an improved patch based on your comments.
Not only does it not care about the PID_MAX value,
it searches all the contents to be output to recognize the required column width
and dynamically allocates the space for PID and PPID appropriately without
creating a lot of empty space.
Additionally, this patch still allows user names to be displayed up to 8
characters without truncation.
Can you look through the attachment?
Unfortunately the patch does not apply to current master.
How much would your patch add to the size? Can you bring it down to a
minimum?
See make baseline; apply the patch;make bloatcheck
thanks
(0002-Allocate-PID-PPID-space-dynamically-in-top-command.patch)
BR-Matthew Chae
________________________________
From: David Laight <[email protected]>
Sent: Thursday, November 23, 2023 6:10 PM
To: 'Denys Vlasenko' <[email protected]>; Matthew Chae
<[email protected]>
Cc: [email protected] <[email protected]>; Christopher Wong
<[email protected]>
Subject: RE: fix large PID overflow their column in top command
...
+ fp = xfopen_for_read("/proc/sys/kernel/pid_max");
+ if (!fgets(pid_buf, PID_DIGITS_MAX + 1, fp)) {
...
+ if (strncmp(pid_buf, "32768", 5) == 0)
+ pid_digits_num = 5;
+ else
+ pid_digits_num = PID_DIGITS_MAX;
The logic above is not sound. Even if sysctl kernel.pid_max
is 32768, there can be already running processes with pids > 99999.
It's also probably wrong for pretty much all other values.
I'd just base the column width on strlen(pid_buf) with a minimum
value of 5.
It is unlikely that pid_max has been reduced - so column overflow
it that case probably doesn't really matter.
The more interesting case is really a system with a very large pid_max
that has never run many processes.
You don't really want lots of blank space.
I can't remember whether top reads everything before doing any output?
Since the output is sorted it probably almost always does.
In which case it knows the column width it will need.
I did post a patch a while back that enabled 'Irix mode'.
(100% cpu is one cpu at 100%, not all cpus at 100%)
Maybe I should dig it out again.
David
-
Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT,
UK
Registration No: 1397386 (Wales)
From 5a1d02b8b0dcfb49be2494aa58db1895729e44c3 Mon Sep 17 00:00:00 2001
From: Matthew Chae <[email protected]>
Date: Thu, 29 Feb 2024 15:09:02 +0100
Subject: [PATCH] Allocate PID/PPID space dynamically in top command
The presence of a large number of PID and PPID digits in the column may
cause overflow, making it impossible to display the entire data
accurately. This dynamically allocates the appropriate space for the
number of digits in the PID and PPID, ensuring the correct
representation of values in each column and guaranteeing a clean
display.
Reviewed-by: Christopher Wong <[email protected]>
Signed-off-by: Matthew Chae <[email protected]>
---
procps/top.c | 63 +++++++++++++++++++++++++---------------------------
1 file changed, 30 insertions(+), 33 deletions(-)
diff --git a/procps/top.c b/procps/top.c
index 09d31c673..a127e455e 100644
--- a/procps/top.c
+++ b/procps/top.c
@@ -637,9 +637,35 @@ typedef struct { unsigned quot, rem; } bb_div_t;
# define FMT "%4u%%"
#endif
+ int lines = lines_rem - 1;
+ unsigned pid_max = 0;
+ unsigned ppid_max = 0;
+ unsigned pid_digits_max = 0;
+ unsigned ppid_digits_max = 0;
+ top_status_t *s_tmp = top + G_scroll_ofs;
+
+ if (lines > ntop - G_scroll_ofs)
+ lines = ntop - G_scroll_ofs;
+
+ while (--lines >= 0) {
+ pid_max = MAX(pid_max, s_tmp->pid);
+ ppid_max = MAX(ppid_max, s_tmp->ppid);
+ s_tmp++;
+ }
+
+ pid_digits_max = strlen(utoa(pid_max));
+ ppid_digits_max = strlen(utoa(ppid_max));
+
+ pid_digits_max = MAX(5, pid_digits_max);
+ ppid_digits_max = MAX(5, ppid_digits_max);
+
/* what info of the processes is shown */
+ printf(OPT_BATCH_MODE ? "%*s%s %*s%s " : ESC"[7m" "%*s%s %*s%s " ESC"[m",
+ pid_digits_max - 3, " ", "PID", /* The length of the PID string : 3 */
+ ppid_digits_max - 4, " ", "PPID"); /* The length of the PPID string : 4 */
+
printf(OPT_BATCH_MODE ? "%.*s" : ESC"[7m" "%.*s" ESC"[m", scr_width,
- " PID PPID USER STAT VSZ %VSZ"
+ "USER STAT VSZ %VSZ"
IF_FEATURE_TOP_SMP_PROCESS(" CPU")
IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE(" %CPU")
" COMMAND");
@@ -696,9 +722,6 @@ typedef struct { unsigned quot, rem; } bb_div_t;
lines_rem = ntop - G_scroll_ofs;
s = top + G_scroll_ofs;
while (--lines_rem >= 0) {
- int n;
- char *ppu;
- char ppubuf[sizeof(int)*3 * 2 + 12];
char vsz_str_buf[8];
unsigned col;
@@ -709,39 +732,13 @@ typedef struct { unsigned quot, rem; } bb_div_t;
smart_ulltoa5(s->vsz, vsz_str_buf, " mgtpezy");
/* PID PPID USER STAT VSZ %VSZ [%CPU] COMMAND */
- n = sprintf(ppubuf, "%5u %5u %-8.8s", s->pid, s->ppid, get_cached_username(s->uid));
- ppu = ppubuf;
- if (n != 6+6+8) {
- /* Format PID PPID USER part into 6+6+8 chars:
- * shrink PID/PPID if possible, then truncate USER.
- * Tested on Linux 5.18.0:
- * sysctl kernel.pid_max=4194304 is the maximum allowed,
- * so PID and PPID are 7 chars wide at most.
- */
- char *p, *pp;
- if (*ppu == ' ') {
- do {
- ppu++, n--;
- if (n == 6+6+8)
- goto shortened;
- } while (*ppu == ' ');
- }
- pp = p = skip_non_whitespace(ppu) + 1;
- if (*p == ' ') {
- do
- p++, n--;
- while (n != 6+6+8 && *p == ' ');
- overlapping_strcpy(pp, p); /* shrink PPID */
- }
- ppu[6+6+8] = '\0'; /* truncate USER */
- }
- shortened:
col = snprintf(line_buf, scr_width,
- "\n" "%s %s %.5s" FMT
+ "\n" "%*u %*u %-8.8s %s %.5s" FMT
IF_FEATURE_TOP_SMP_PROCESS(" %3d")
IF_FEATURE_TOP_CPU_USAGE_PERCENTAGE(FMT)
" ",
- ppu,
+ pid_digits_max, s->pid, ppid_digits_max, s->ppid,
+ get_cached_username(s->uid),
s->state, vsz_str_buf,
SHOW_STAT(pmem)
IF_FEATURE_TOP_SMP_PROCESS(, s->last_seen_on_cpu)
--
2.30.2
function old new delta
display_process_list 1406 1503 +97
.rodata 99900 99918 +18
------------------------------------------------------------------------------
(add/remove: 0/0 grow/shrink: 2/0 up/down: 115/0) Total: 115 bytes
text data bss dec hex filename
1011743 16507 1840 1030090 fb7ca busybox_old
1011858 16507 1840 1030205 fb83d busybox_unstripped
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